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Car Forum / Ford / Ford Cars / May 2007

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4.6 Motor Question

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Me - 24 Apr 2007 01:06 GMT
I recently purchased a 2002 E150. My question is that it recommends 5w-20
motor oil. Isn't this to light weight of a motor oil during the summer? I am
afraid the motor will get hot during the stop and go of the big city.
Allowing parts failure due to the oil getting to thin when hot.

Can someone please advise.

Thanks

Kevin
RD Jones - 24 Apr 2007 01:44 GMT
> I recently purchased a 2002 E150. My question is that it recommends 5w-20
> motor oil. Isn't this to light weight of a motor oil during the summer? I am
> afraid the motor will get hot during the stop and go of the big city.
> Allowing parts failure due to the oil getting to thin when hot.

You must be an old timer like me, used to using 20w-50 in everything ;-

The engine will get hot, yes. All newer engines have closer tolerences
that benefit from the lighter oils, and the result is lower emissions
and
better gas mileage, so says the Gov't.

Check the manual for the temp range for the oil weight.
It may recommend a slightly heavier oil for very hot summer
running but probably not any higher that 5w-30.

If you're worried about the oil breaking down, use synthetic.
I wouldn't advise using a much higher weight, though.

rd
clare at snyder.on.ca - 24 Apr 2007 02:26 GMT
>> I recently purchased a 2002 E150. My question is that it recommends 5w-20
>> motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 16 lines]
>
>rd

You can run 10W40 oil in the 4.6 as long as you change it at leat
every 5000 miles - 3500 is better (due to the viscosity shear in high
VI conventional oils).  You will loose a small amount of fuel
efficiency - C.A.F.E. is the major driving force behind the ultra thin
engine oils. The engine clearances have changed VERY LITTLE over the
last 30 years. Engine finishes have improved, allowing closer absolute
fits on some parts (while maintaining approxemately the same average
clearances)

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dpryal@comcast.net - 24 Apr 2007 02:51 GMT
> >> I recently purchased a 2002 E150. My question is that it recommends 5w-20
> >> motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 30 lines]
>
> - Show quoted text -

My Masda also requires 5w20.  Dealer told me it may have something to
do with oil filter not suited to handle heavy oil.
clare at snyder.on.ca - 24 Apr 2007 03:14 GMT
>> >> I recently purchased a 2002 E150. My question is that it recommends 5w-20
>> >> motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 33 lines]
>My Masda also requires 5w20.  Dealer told me it may have something to
>do with oil filter not suited to handle heavy oil.

Same filter used in pre 5W20 engines. However, the small filters DO
bypass most of the oil when cold, even with 5W20. Using a larger than
factory supplied filter will improve cold lubrication and filtration.
(assuming you can find one that fits)

When the filter goes into bypass, the oil pressure in the engine is
substantially lower than the pressure shown on the guage (but a lot
better than it would be if the bypass didn't open)
The engine will run just fine with a totally plugged filter - but no
fltering will occur and eventually damage will occur. Lots of early
engines had no filters at all.

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lugnut - 24 Apr 2007 03:18 GMT
>> I recently purchased a 2002 E150. My question is that it recommends 5w-20
>> motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 16 lines]
>
>rd

The 5w20 spec Ford uses is a synthetic blend oil which can
handle the higher temps with no problem.  It gives quick
lubrication on cold start and, reportedly, saves a little
fuel.  If you do not use this, either use a full synthetic.
or a good quality 5w30 or 10w30 oil.  The 5w30 will result
in quicker cold start oil flow than 10w30 which is
desireable.  If you drive longer periods where the engine is
warm pretty much all the time, the 10w30 would work just as
well.  If the engine is never shut down and allowed to cool,
a straight 30 will do as well as any.  The cold starts are
the bitch for the engine lube system.

Lugnut
trainfan1 - 24 Apr 2007 01:54 GMT
> I recently purchased a 2002 E150. My question is that it recommends 5w-20
> motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 6 lines]
>
> Kevin

Use 5W-20 or 5W-30 synthetic and don't worry about it.  It's a water
cooled engine, it will get hot no matter which oil you are using.
Regular preventative maintenance(cooling system included) is the key.
Use Ford spec WSS-M2C153-F oil or better & you'll be fine.

Rob
Picasso - 24 Apr 2007 02:02 GMT
> I recently purchased a 2002 E150. My question is that it recommends 5w-20
> motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 6 lines]
>
> Kevin

I dunno, at work 10w30 goes in all the new ford motors, the 3.0L rangers
and the 4.6L f150s alike, and the 5.4s as well
Ed White - 24 Apr 2007 03:48 GMT
> I recently purchased a 2002 E150. My question is that it recommends 5w-20
> motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 6 lines]
>
> Kevin

Ford doesn't just blindly recommend 5W20 oil for all of its engines.
For instance, the 4.0L SOHC V-6 sold in Explorers and Mustangs still
requires 5W30. The diesel engines also require a different oil. 5W20
oil that meets the Ford specifications has to be very good quality
oil. Toyota and Honda are also recommending 5W20 (and/or 0W20) oil for
their newer engines. When I first got a Ford that specified 5W20 oil,
I was also concerned. However after reading available SAE literature
and Fords' explanation I came to believe that the 5W20 oil is a good
choice (as long as it meets the appropriate Ford specs). The only time
I might consider using oil with a higher viscosity is when hauling/
towning a heavy load at high speed in high temperatures for a
substained period of time. I recently traded off an Expedtion with a
5.4L engine. For most of the time I owned the truck, I used the Ford
5W20 oil. When I traded off the truck, the engine ran perfectly and
never needed any oil added beteween changes.

Ed
Ashton Crusher - 24 Apr 2007 06:33 GMT
>I recently purchased a 2002 E150. My question is that it recommends 5w-20
>motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 6 lines]
>
>Kevin

When these first came out they called for 10W30 for typical
temperatures.  Then the car makers wanted to get another 1% better gas
mileage and developed the 5W20.  The most I have ever heard them claim
is that there tests with the 5W20 shows it to be adequate.  Hardly a
great recommendation and to get it to that point of adequacy they had
to go to semi-synthetic whereas the prior oil had no trouble being
"adequate" as a straight dino oil.  I continue to use 10W30 in my 99
4.6
clare at snyder.on.ca - 25 Apr 2007 02:04 GMT
>>I recently purchased a 2002 E150. My question is that it recommends 5w-20
>>motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 15 lines]
>"adequate" as a straight dino oil.  I continue to use 10W30 in my 99
>4.6
I run 10W40 in my Duratec 2.5

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C. E. White - 25 Apr 2007 13:27 GMT
> When these first came out they called for 10W30 for typical
> temperatures.  Then the car makers wanted to get another 1% better
[quoted text clipped - 7 lines]
> "adequate" as a straight dino oil.  I continue to use 10W30 in my 99
> 4.6

Ford never recommended 10W30 for a 1999 4.6L engine. The oil
originally recommended in 1999 was 5W30 (Ford Spec
WSS-M2C153-G). A later TSB recommended the use of 5W20 oil in 1999
4.6L engines. I've never understood why anyone uses 10W30 instead of
5W30. At operating temperature there is virtually no difference in
viscosity. When cold, both oils are more viscous than either oil is
when it is warm, but the 5W30 is slightly less viscous and therefore a
better choice for a cold engine. I've never seen any claims that 5W30
is significantly more likely to break down than 10W30 (unlike 10W40
which was alleged to suffer from significant break down problems - at
least when originally introduced). The only reason I can see for using
10W30 over 5W30 is cost ($0.10 to $0.20 a quart).

In the US the commonly available 5w20 Ford Oil is a Synthetic Blend
(SAE 5W-20 Premium Synthetic Blend Motor Oil - Red Bottle). In Canada
the commonly available Ford 5W20 oil is a straight non-synthetic oil
(SAE 5W-30 Super Premium Motor Oil - black bottle). I am not sure why
there is a difference (suppliers perhaps). However, even the
non-synthetic blend version is supposedly a very good oil.

Ed
clare at snyder.on.ca - 26 Apr 2007 21:51 GMT
>> When these first came out they called for 10W30 for typical
>> temperatures.  Then the car makers wanted to get another 1% better
[quoted text clipped - 20 lines]
>least when originally introduced). The only reason I can see for using
>10W30 over 5W30 is cost ($0.10 to $0.20 a quart).

The 10W40 today is excellent if you don't try to run it too long. 3500
mile changes are no problem. 7000 mile intervals you are begging for
trouble (but then, I'd not go 7000 on 5W30 either - same viscosity
spread, means same amount of VI improvers, and the same propensity to
"shear".

>In the US the commonly available 5w20 Ford Oil is a Synthetic Blend
>(SAE 5W-20 Premium Synthetic Blend Motor Oil - Red Bottle). In Canada
[quoted text clipped - 4 lines]
>
>Ed

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Sharon Cooke - 24 Apr 2007 14:52 GMT
> I recently purchased a 2002 E150. My question is that it recommends 5w-20
> motor oil. Isn't this to light weight of a motor oil during the summer? I am
[quoted text clipped - 6 lines]
>
> Kevin

If your vehicle has an oil pressure gauge - pay attention to that for
your viscosity concerns, but FIRST verify that the gauge is a REAL one,
and not the disguised idiot light that Ford likes to put in vehicles.
The tell is the oil sender by the oil filter: button type sender = fake
gauge, can type sender = real gauge.
C. E. White - 25 Apr 2007 13:11 GMT
> If your vehicle has an oil pressure gauge - pay attention to that
> for your viscosity concerns, but FIRST verify that the gauge is a
> REAL one, and not the disguised idiot light that Ford likes to put
> in vehicles. The tell is the oil sender by the oil filter: button
> type sender = fake gauge, can type sender = real gauge.

Ford hasn't used anything but the single position indicator type gauge
for at least a decade (except on HD trucks). And it is not just Ford,
GM has also gone to this type of gauge, as has Nissan. Unless you are
going to spend the money to calibrate the sender and gauge system and
educate the users, having a "real" gauge that moves around is a waste.
The last variable gauge I had in a Chrysler was totally worthless. It
moved around all over the place, but the readings were only loosely
related to the actual engine oil pressure. It worried me greatly. I
finally installed an actual direct reading pressure gauge to verify
there was no actual problem.

Ed
Sharon Cooke - 25 Apr 2007 17:07 GMT
>>If your vehicle has an oil pressure gauge - pay attention to that
>>for your viscosity concerns, but FIRST verify that the gauge is a
[quoted text clipped - 14 lines]
>
> Ed

There are people that believe knowing the engine’s oil pressure is vey
important, and will go to some lengths to get it. See:
http://neptune.spacebears.com/cars/stories/oilgauge.html
and:
http://www.miata.net/garage/opg.html

All of my vehicles have functional oil pressure gauges AND the idiot lights.
It really makes me nervous to drive a vehicle any distance at highway
speed that doesn’t have an actual oil pressure gauge. Oil pressure in an
engine can decline over time due to bearing wear, oil pump, clogged sump
screen, filter, etc., and if the idiot light comes on at 70 mph, it’s
usually time for a new engine.
C. E. White - 26 Apr 2007 12:46 GMT
> There are people that believe knowing the engine’s oil pressure is
> vey important, and will go to some lengths to get it. See:
[quoted text clipped - 9 lines]
> pump, clogged sump screen, filter, etc., and if the idiot light
> comes on at 70 mph, it’s usually time for a new engine.

All that is fine for you, since you have may know the correct oil
pressure and might actually take action if it is not correct. For the
typical driver what does he learn from a full function oil pressure
gauge? How many people know what the minimum acceptable idle pressure
is. How about the acceptable 2000 rpm pressure is? Ford specifies that
the oil pressure for a 4.6L V-8 should be 40 to 60 psi at 2000 rpm
with the oil hot (and I am assuming the use of 5W20 oil). Is there any
reason to think 40 psi  is better than 60 psi? Ford's assumption is
that if you have enough oil pressure at idle to close the switch for
the indicator, that the oil pump is working and the filter is not
plugged. If the pump is working and oil is flowing at idle, what could
be wrong that would affect lubrication at higher rpms? Worn pump? If
the pump is worn so badly that it can't make decent pressure at 2000
rpm, it probably can't make 7 psi at idle - and the light should come
on. Worn bearings? If the bearing are worn so badly that the pump
can't produce enough oil to keep up the pressure at 2000 rpm, then the
engine is already toast.

It is important that your oil pump supplies enough volume of oil to
the places where it is needed. Pressure is almost irrelevant as long
as you maintain an adequate flow. You are using the oil pressure
reading as a indicator that this is happening, but it is only a
secondary indicator. You can have high oil pressure and still not
provide proper lubrication. And you can have low pressure while
providing adequate lubrication. People get into the "more is better"
mode, but in the case of oil pressure this is not always true.

Consumer grade electrical oil pressure gauges are notoriously
inaccurate - particularly over a long period of time. They may well
have better than 5% accuracy when new, but over a period of time they
drift significantly. Mechanical gauges are better at remaining
accurate over time, but then you have the danger of a failed oil line.
It is no fun having hot oil dribble onto your feet.

"Real" variable reading oil pressure gauges might be useful to a small
number of individuals who understand the readings, who actually pay
attention to the readings, and who might actually take some action
based on the readings, BUT for the vast majority of car owners, the
go/no go type of gauge is the proper choice. To me the go/no go type
of gauge is better than the "low oil pressure" light alone, since it
is a positive indicator that you have the minimum oil pressure.

Ed
Sharon Cooke - 26 Apr 2007 13:11 GMT
>>There are people that believe knowing the engine’s oil pressure is
>>vey important, and will go to some lengths to get it. See:
[quoted text clipped - 53 lines]
>
> Ed

What is a "go/no go type of gauge"? You mean the idiot light DISGUISED
as an analog gauge? Probably LESS useful than the idiot light, except as
a feel good kind of thing, since it won’t even call attention to itself
as well as an idiot light if something goes wrong, and is also useless
for indicating a pressure drop trend.
As far as knowing oil pressure ranges on a real gauge (electric is just
as "real" as a mechanical one) for a particular vehicle go, I do know,
since I have the factory service manuals for all my vehicles. The
electric gauges DO read a hair low compared to my Snap-On test
mechanical gauge, but so what? I’d rather have them read a little too
low than a little too high. I also check the electric gauges(s) readings
with the mechanical test gauge every time I change the oil and filter at
10K miles; Mobil One 5W30 on all.
Tom Adkins - 26 Apr 2007 13:40 GMT
> What is a "go/no go type of gauge"? You mean the idiot light DISGUISED
> as an analog gauge? Probably LESS useful than the idiot light, except as
[quoted text clipped - 9 lines]
> with the mechanical test gauge every time I change the oil and filter at
> 10K miles; Mobil One 5W30 on all.

 Your missing his point. You are among the 2% of people that actually look at, know
how to interpret, and will respond to, a real oil pressure gauge. Most drivers haven't
a clue. How many times have you heard inquiries that started with "My xxxxx light has
been coming on for about a month..." For the majority, the go/no-go gauge or light is
actually better than a gauge. A light will at least get their attention.
Fordfan - 30 Apr 2007 10:11 GMT
>  Your missing his point. You are among the 2% of people that actually
> look at, know how to interpret, and will respond to, a real oil pressure
> gauge. Most drivers haven't a clue. How many times have you heard
> inquiries that started with "My xxxxx light has been coming on for about
> a month..." For the majority, the go/no-go gauge or light is actually
> better than a gauge. A light will at least get their attention.

I knew someone that thought the oil light was supposed to be a reminder
to change the oil.
Tom Adkins - 30 Apr 2007 15:37 GMT
>>  Your missing his point. You are among the 2% of people that actually
>> look at, know how to interpret, and will respond to, a real oil
[quoted text clipped - 5 lines]
> I knew someone that thought the oil light was supposed to be a reminder
> to change the oil.

 Or how about a low oil level indicator. True story:
 A long time customer had an early 70s Buick. Very well maintained, high mileage. As
was common on Buick engines of that vintage, the oil pump was weak and the oil lamp
would flicker at idle on hot days.
 He gave the car to his 30ish yo son. After a few weeks, the son brings the car in
pouring oil from every opening and barely running. I drained 7 gallons of oil out of
that engine! When the oil light would flicker, he would add a quart or 2 of oil. He
"estimated" 2 quarts at a time by the amount of oil running down his driveway!!
 The father was such a smart man and well informed customer, he was a retired
Steelworker. The son had a Masters in Electrical Engineering. Go figure!
El Bandito - 06 May 2007 05:51 GMT
>>>  Your missing his point. You are among the 2% of people that actually
>>> look at, know how to interpret, and will respond to, a real oil
[quoted text clipped - 19 lines]
> retired Steelworker. The son had a Masters in Electrical Engineering. Go
> figure!

my sister added some oil whenever the idiot light came on.

she blew out a head gasket on her fox..

Please bring back *analog* gauges...

They are not that hard to read.

Signature

Don't drink water, fish have sex in it!

Ashton Crusher - 06 May 2007 07:59 GMT
>>>>  Your missing his point. You are among the 2% of people that actually
>>>> look at, know how to interpret, and will respond to, a real oil
[quoted text clipped - 21 lines]
>
>my sister added some oil whenever the idiot light came on.

What makes you think she would have done any different with a gauge??
Very possibly she would not have noticed the problem at all with a
gauge.  At least with a light there's something bright and shiny to
attract their attention.

>she blew out a head gasket on her fox..
>
>Please bring back *analog* gauges...
>
>They are not that hard to read.
C. E. White - 26 Apr 2007 15:05 GMT
> What is a "go/no go type of gauge"? You mean the idiot light
> DISGUISED as an analog gauge? Probably LESS useful than the idiot
> light, except as a feel good kind of thing, since it won’t even call
> attention to itself as well as an idiot light if something goes
> wrong, and is also useless for indicating a pressure drop trend.

A go/no go gauge is exactly what it is. It is a positive indicator. If
you only have the light, you only have a negative indicator. The light
might not be on because the oil pressure is good, but it might also
might not be on because the light circuit is bad. With the go/no go
type gauge you have a positive indication that you have sufficient
pressure. If the gauge doesn't come up to pressure it might be because
you have no pressure, or it might be because the gauge circuit is bad,
but either way you know something is wrong.

As for indicating trends - you seem to be very attentive and
understand the reasons for oil pressure fluctuations. What percentage
of car owners do you think that applies to?

> As far as knowing oil pressure ranges on a real gauge (electric is
> just as "real" as a mechanical one) for a particular vehicle go, I
[quoted text clipped - 5 lines]
> time I change the oil and filter at 10K miles; Mobil One 5W30 on
> all.

Well you sound like a really attentive vehicle owner. Now for the big
question - has all this attention to changing oil pressure made any
significant difference? Have you saved an engine because you saw the
oil pressure slowly decreasing over time? For me, I've never had an
oil related failure of any kind. My oldest "vehicle" is a 1981 Ford
7710 Tractor. It just turned over 6000 hours (rated speed for the hour
meter is 1900 rpm). It only has an oil pressure warning light. I've
never really worried that it doesn't have a gauge. One of my newer
tractors has a oil pressure gauge, but it isn't calibrated. It is
backed up by both a light and a warning horn (plus a failure will
display STOP on the main dash display). The gauge is just a bar graph
thing that has no values. It is totally worthless, but it does change
over time. On a hot day when you work the tractor hard, it reads lower
than on a cool day when you are putting around. Over the years, it has
trended lower. But so what? What should I do as a result of the
entirely predictable changes? Nothing is what I've done. The gauge has
been no more useful than just the warning light on the other tractor.

Ed
Sharon Cooke - 26 Apr 2007 16:20 GMT
>>What is a "go/no go type of gauge"? You mean the idiot light
>>DISGUISED as an analog gauge? Probably LESS useful than the idiot
[quoted text clipped - 44 lines]
>
> Ed

Oil pressure trending lower over many years usually just means normal
main bearing and crank wear, but dropping in days or even hours could be
a blown head gasket or failing oil pump. In one of those situations, by
the time the idiot light comes on or the fake gauge SUDDENLY drops to
zero, it's time for a new engine.

The same three vehicles I've had for many years:
1990 Lincoln Mark VII - 158.9K miles
1994 Lincoln Mark VIII - 109.8K miles
1990 Toyota Truck - 237.8K miles
A combined total of over 1/2 million miles with 10K oil changes and ZERO
internal engine problems on any of the vehicles.

I did have the idiot light on the Mark VIII turn on once at 70 mph, but
the OP gauge was showing a steady 60 psi, so I just kept going. When I
got the car up on ramps at home, I found it was the factory oil pressure
snap switch that had failed; without the real OP gauge, I would have
been really inconvenienced out there on I-35 at 2 AM, so I’ll just keep
running with OP gauges in all my vehicles.

I also have voltmeter gauges on all my vehicles, since I don’t trust the
other idiot light for the charging system either. :)
Ed White - 26 Apr 2007 20:56 GMT
> Oil pressure trending lower over many years usually just means normal
> main bearing and crank wear, but dropping in days or even hours could be
> a blown head gasket or failing oil pump. In one of those situations, by
> the time the idiot light comes on or the fake gauge SUDDENLY drops to
> zero, it's time for a new engine.

And how often does this happen? I've had a couple of head gaskets fail
in my life, and both times the first symptom was overheating. I
suppose you can get a massive oil leak, but a massive coolant leak
seems more likely. And even when oil pumps were driven off the
distributor gear, gradual failures were uncommon. With todays crank
driven pumps, it is much more likely that an oil pump failure will be
sudden and in that case the light is as good as a gauge.

> The same three vehicles I've had for many years:
> 1990 Lincoln Mark VII - 158.9K miles
> 1994 Lincoln Mark VIII - 109.8K miles
> 1990 Toyota Truck - 237.8K miles
> A combined total of over 1/2 million miles with 10K oil changes and ZERO
> internal engine problems on any of the vehicles.

I haven't had any sort of significant engine failure in over 20 years.
The last time I had one was a 1978 Fiesta with a 140,000 miles. I
managed to burn a piston (clogged EGR, and drving flat out for 35
miles). I have a 35 year old Dodge dump truck with an unknow number of
miles (well over 100,000). The only thing that has failed in the oil
system is the crappy electric oil pressure gauge.

> I did have the idiot light on the Mark VIII turn on once at 70 mph, but
> the OP gauge was showing a steady 60 psi, so I just kept going. When I
> got the car up on ramps at home, I found it was the factory oil pressure
> snap switch that had failed; without the real OP gauge, I would have
> been really inconvenienced out there on I-35 at 2 AM, so I'll just keep
> running with OP gauges in all my vehicles.

For you it seems like a reasonable thing. You understand what gauge
movements mean and you pay attention to the gauges. I am suggesting
that you are the exception. Most vehicle owners don't pay attention to
the gauges, and when they do, they often misinterpert them. It must
really upset you that car makers are now installing computer
controlled temperature gauges. The gauges appear to move like old
style gauges, but actually the needle position is determined by the
PCM and not the water temperature.  Both my current Nissan and Fords
have this sort of gauge. They are not completely go/no go gauges, more
a sort of incremental gauge with the position dictated by the PCM.

> I also have voltmeter gauges on all my vehicles, since I don't trust the
> other idiot light for the charging system either. :)-

I am surprised you don't have an old style ammeter. Voltage meters are
OK, but to be truly useful they need to be calibrated. The OEM ones
just have a few poorly located markings and by the time you figure the
voltage is too low, it can be too late. Even with the poor quality OEM
gauges, if you pay careful attention to the position of the needle you
can determine that it is lower than normal, but again this is only
useful for people who pay attention and understand what voltage gauge
movements imply.

Most OEM gaguges are just for looks. They aren't particularly well
calibrated and in many cases aren't direct reading gauges. It used to
be that the Germans actually included calibrated gauges, but it has
been a couple of decades since I owned a German car. I have no idea
what the Germans are doing these days. In recent years I have owned
Japanese and Domestic cars that use non-calibrated, poorly marked
gauges that are no better than go/no go indicators.

Ed
Sharon Cooke - 26 Apr 2007 22:28 GMT
>>Oil pressure trending lower over many years usually just means normal
>>main bearing and crank wear, but dropping in days or even hours could be
[quoted text clipped - 63 lines]
>
> Ed

No way that I'm putting an ammeter into a Ford product, since they tend
to burst into flame quite well without the "outside help" of an
aftermarket ammeter install. In any event, a voltmeter is much more
useful than an ammeter, and WAY safer, per this article:
http://www.egauges.com/ATM_Tips.asp?TipPage=voltmeterammeter.htm
C. E. White - 27 Apr 2007 12:57 GMT
> No way that I'm putting an ammeter into a Ford product, since they
> tend to burst into flame quite well without the "outside help" of an
> aftermarket ammeter install. In any event, a voltmeter is much more
> useful than an ammeter, and WAY safer, per this article:
> http://www.egauges.com/ATM_Tips.asp?TipPage=voltmeterammeter.htm

I agree with the major points of the article. If you have a good
voltmeter and pay careful attention it is very useful. However, the
last few OEM voltmeters in vehicles I've owned only had markings at
the extreme, so you had to "guess" where 14 volts was. One of my OEM
voltmeters always seemed to drift higher on long trips, and this
worried me. I thought it was some sort of alternator problem. I
finally checked it with a real voltmeter and determined it was the
gauge that was drifting. However, I don't suppose I could claim it was
"faulty" since it was indicating a voltage somewhere between 11 and 18
volts, and it never got to the "red" on either end of the scale. I am
very suspicious of the voltmeter in my current Nissan Frontier - it
never moves when the truck is running. Either this truck has a super
duper alternator, or the voltmeter is also a computer controlled
gauge. I can't tell from the wiring diagram since the wiring harness
just disappears into the IP module. If you really want to know what is
going on with your electrical system, having both a voltmeter and an
ammeter is better than either alone. With the voltmeter, you know the
"pressure" in the system, with the ammeter you know the "flow" to and
from the battery. If you have a good alternator, the voltmeter is
always going to be in the 13.5 to 14.5 volt range with the vehicle
running unless there is a major problem. If you also have an ammeter,
and it shows significant current draws, even when most accessories are
off, then you know you have a problem.

The article is wrong on one point - you don't have to run all the
wires through an ammeter in your dash. There are remote sensing
ammeters where the only thing transmitted to the gauge is an indicator
voltage. You might want to look at
http://www.siliconchip.com.au/cms/A_30551/article.html  for an example
of how this works. My old 800 Ford Tractor had an even simpler sort of
ammeter. It did run the main power lead through the ammeter, but there
was no physical break in the power lead. The ammeter had a loop that
the main power lead ran through and this "detected" the current flow.
With modern vehicles with scores of circuits this is impractical, but
a remote senor like shown in the example on the web page can be
applies at the main batter connection and transmit an indicator
voltage to the dash gauge.

Ed White
clare at snyder.on.ca - 26 Apr 2007 21:57 GMT
>Oil pressure trending lower over many years usually just means normal
>main bearing and crank wear, but dropping in days or even hours could be
>a blown head gasket or failing oil pump. In one of those situations, by
>the time the idiot light comes on or the fake gauge SUDDENLY drops to
>zero, it's time for a new engine.

Or fuel dilution (on a pre OBD2 engine - OBD2 will throw a code if an
injector leaks- unless the engine isn't running) or oil viscosity
breakdown (which has happened to me) or "foaming" which has happened
on my brother's car - both due do crappy oil. Saved both engines by
getting an oil change IMMEDIATELY upon noticing the pressure drop.

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B.B. - 30 Apr 2007 02:01 GMT
[...]

>Consumer grade electrical oil pressure gauges are notoriously
>inaccurate - particularly over a long period of time. They may well
>have better than 5% accuracy when new, but over a period of time they
>drift significantly. Mechanical gauges are better at remaining
>accurate over time, but then you have the danger of a failed oil line.
>It is no fun having hot oil dribble onto your feet.

  I come from the world of heavy commercial truck repair.  Never seen a
pressure gauge or hose dump oil behind the dash.  The electronic dashes
use transducers that cost $15 from the dealership and rarely fail and
are always accurate within 2 or 3 psi when checked against my mechanical
gauge.  I have seen one inaccurate transducer; owner brought it in for
low oil pressure.  Everyone else who complains of low oil pressure needs
an overhaul.  
  Most drivers are too stupid to know what is or isn't good oil
pressure, and I see quite a few drivers dump that lucas sh.t in the
engine to get the psi higher.  But I don't think that's a good argument
to use an idiot light over a real gauge.
  I do not know of any commercial truck makers that equip $20,000
engines with just idiot lights.  All of the recent gauges are however
equipped with an idiot light in addition to the needle.  Comes on with
low pressure, loss of signal, or excessively high signal.  LED "bulb."  
Seems to me an optimum compromise.  Needle for drivers who read the
book, light for drivers who don't.
  Granted, it's a different market, where engines do routinely wear out
simply due to mileage and most drivers do not own the driven vehicles.  
But direct-reading gauges aren't difficult or expensive.

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B.B.           --I am not a goat!       thegoat4 at airmail dot net

 
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