>> >When I turn off ignition even for one
>> >minute then re-start, gauge drops right back down to normal range
[quoted text clipped - 16 lines]
>
>Have to disagree here. First, a bubbling overflow tank is not normal.
Hi Codifus,
When the engine is cold the water level in the overflow resevoir will
be at "cold" marking. You start the engine, the water heats up, and
expands into the overflow tank, and the level rises to the "hot"
marking. Wont you get bubbling at this time? No, you are probably
correct, there should be little or no air in the system, so there
should little no bubbling as the engine heats up.
>Something's wrong. And regarding the coolant temp sensor; when it
>fails, the car tends to run cooler than normal.
Again I bow to your superior knowledge. All I really know is that if
the coolant temperature sensor is faulty, you will get a faulty
temperature reading.
If the coolant temperature sensor is faulty, how does that make the
engine run cooler. What does the coolant temperature sensor affect?
the thermostat, fans, some other temperature adjusting mechanism?
Educate me please.
Al Moodie
>CD
codifus - 29 May 2007 16:51 GMT
> >> >When I turn off ignition even for one
> >> >minute then re-start, gauge drops right back down to normal range
[quoted text clipped - 42 lines]
>
> >CD
OK, regarding the temp sensors, on this maxima there are 2. One sensor
actually tells the ECU what tempurature the car is. The other one is
linked to the temp gage that you view on the instrument panel.
The ECU one is the important, critical one.
When that sensor fails, it tends to under-report the tempurature to
the ECU. If the car's real temp is 240 degrees, a failing sensor will
tell the ECU is 140 degress. The ECU then thinks that the car is still
cold, thereby keeping the fuel maps on the rich side, you know, like
when you first start the car in winter. Running rich makes a car run
cooler because of the excess, and hence unburnt, feul being thrown
into the cylinders.
Symptoms of a bad temp sensor: weaker engine, bad gas mileage.
CD
E Meyer - 29 May 2007 17:06 GMT
On 5/29/07 10:36 AM, in article b7ho5315hnpil58obj3qpc9v4uo2av3jt9@4ax.com,
>>>> When I turn off ignition even for one
>>>> minute then re-start, gauge drops right back down to normal range
[quoted text clipped - 32 lines]
> the coolant temperature sensor is faulty, you will get a faulty
> temperature reading.
Most of the the Maximas have two temperature sensors, one that feeds the
gauges and one that feeds the ECU. If the "other" one is bad, you won't see
any cessation of function on the gauge.
> If the coolant temperature sensor is faulty, how does that make the
> engine run cooler. What does the coolant temperature sensor affect?
[quoted text clipped - 5 lines]
>>
>> CD
If you've got obvious flow into the overflow tank as the engine warms from
cold to normal, that usually means a bad radiator cap is opening at too low
a pressure. It shouldn't be moving anything into the overflow tank until
its fully warmed up and the pressure in the radiator starts to exceed the
cap rating. In any event, there shouldn't be any bubbles.
If it continues blowing bubbles into the tank and proceeds directly to
overheated, that is a classic symptom of a blown head gasket.
I think your first priority is finding the source of the bubbles - seeping
water pump, pin hole in a hose, etc. My daughter's 240SX will behave as you
describe if there is an air bubble trapped in the vicinity of the thermostat
(usually right after a coolant replacement).
KybonaWhogonna - 30 May 2007 22:50 GMT
> On 5/29/07 10:36 AM, in article
> b7ho5315hnpil58obj3qpc9v4uo2av3jt9@4ax.com,
[quoted text clipped - 67 lines]
> thermostat
> (usually right after a coolant replacement).
===
Myself I would find a good radiator repair shop and get it fixed before you
ruin the engine.
O.K. I appreciate all responses, let me ask this.
I have seen an additive called "Water Wetter" made by a company called
"Redline" It states that it will reduce engine temp. by 20 degrees and
is perfectly safe to add to the existing coolant. Anybody have
experience with this stuff? And is 20 degrees enough to solve my probem?
codifus - 08 Jun 2007 12:23 GMT
> O.K. I appreciate all responses, let me ask this.
> I have seen an additive called "Water Wetter" made by a company called
> "Redline" It states that it will reduce engine temp. by 20 degrees and
> is perfectly safe to add to the existing coolant. Anybody have
> experience with this stuff? And is 20 degrees enough to solve my probem?
It's not a problem solver. Water Wetter just makes your system run
more effficiently. Fix the problem first, then add water wetter.
CD