Oil in radiator 6.2 Diesel

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Mel Riser - 24 Nov 2006 22:23 GMT

A few weeks ago, I noticed my coolant temps go up a bit over normal.
Nothing drastic, just a bit higher than it has been in years.

after about a week, I come outside one morning to find a large puddle
under the truck. Finally traced it to the radiator. Seems that
something is leaking oil into my radiator water.

I ask folks, some say the heads ( truck still runs great ) my father
says probably the oil cooler in the radiator leaking. No anti-freeze in
my oil, but about a quart in the radiator.

I took the radiator off today and a new one is about 400 bucks.

but before I spend that much, I want to confirm with some others if
this might be the issue>?

makes sense to me, as the oil pressure is 30 to 60 pounds, and the
radiator cap is 15 psi.

the oil was leaking from the radiator overflow bucket and when it
filled up, it ran over on the ground.

when I took the radiator cap off, about a quart came out. Since the oil
is lighter than water, the bottom half of the radiator had antifreeze.

So somebody tell me I am on the right track, as i DO NOT want to take
the heads off in an exploratory move...

replacing the radiator is fine with me.

SECOND question. I am looking at an aftermarket oil cooler, and
eliminating the oil cooler in the radiator altogether. anybody have one
of those?

oil cooler is 225, new radiator 400. I could plug the oil cooler lines
and use the same radiator if this is the case.

mel

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Jonathan - 25 Nov 2006 05:30 GMT

Greetings,

First you have some missing information. Need to know if your engine oil
level is lower on the dipstick. If not, then check the fluid level in your
transmission and see if that's the source because unless you have a set-up I
am unfamiliar with, the "oil cooler in your radiator" is actually the
transmission fluid cooler. The actual engine oil cooler is a smaller
seperate radiator that sits either in front of or below your normal radiator
but had no direct connection or shared pieces parts with your radiator. It
is not uncommon for vehicles with radiator issues to have the tranny fluid
leak into the engine coolant from a bad radiator, which cools both fluids
separately inside one unit.

Second, if you believe you have problems with the heads don't pull them just
for an inspection. Do a cylinder pressure test first to see if you are
holding pressure which can point to a bad head gasket a lot easier than
pulling the heads.

You should also do a pressure test on the coolant system as well, which
might tell you if the intake manifold gasket is leaking - although this
would typically put coolant into your engine oil and not engine oil into
your radiator.

Good luck - Jonathan

>A few weeks ago, I noticed my coolant temps go up a bit over normal.
> Nothing drastic, just a bit higher than it has been in years.
[quoted text clipped - 34 lines]
>
> mel

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Steve W. - 25 Nov 2006 14:17 GMT

> Greetings,
>
[quoted text clipped - 8 lines]
> leak into the engine coolant from a bad radiator, which cools both fluids
> separately inside one unit.

GM uses an oil cooler mounted inside the radiator on many vehicles. They
have a trans cooler on one side and the oil cooler on the other. Been in
use since at least 1990.

> Second, if you believe you have problems with the heads don't pull them just
> for an inspection. Do a cylinder pressure test first to see if you are
[quoted text clipped - 7 lines]
>
> Good luck - Jonathan

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Jonathan - 25 Nov 2006 15:01 GMT

Greetings,

You are most likely correct but I've not seen this set-up on any of my GM
trucks. In my last two diesels (a 6.5 and my current Duramax) the oil
cooler was a completely seperate unit and only the tranny cooler was
incorporated into the radiator. While I've tinkered with the older 6.2
diesels I've never owned one like the OP and the only way to be absolutely
sure would be to look at his truck.

Cheers - Jonathan

> GM uses an oil cooler mounted inside the radiator on many vehicles. They
> have a trans cooler on one side and the oil cooler on the other. Been in
> use since at least 1990.

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Mel Riser - 27 Nov 2006 01:15 GMT

OK number one... no automatic transmission, and the only cooler lines
are the oil cooler lines from the motor.

Number two, yes the motor was a bout a quart low when I saw the puddle
under the truck. No antifreeze in the oil.

I could do a compression test on the motor, but I don't think it's the
heads. Motor starts and runs good, plus on diesels, it would run bad
and I would be seeing weird smoke and blow by.

I'm gonna go ahead and pressure test the oil cooler section and see if
that leaks air.

Should be able to do that with an air compressor, as it the oil
pressure on this truck is 60 psi when it starts.

Radiator is out of the truck now. WHEW... and WHAT a MESS. took three
bags of kitty litter to soak it all up.

mel

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