LB7 Coolant in the Oil HELP!

[dgalvin66]

Hello
I have an 02 GMC Sierra 2500HD 4x4 that is my daily driver. I have been driving it since early 2004.
It has just under 200k on it. Never overheated in the Las Vegas desert.
About a week ago there was a Low Coolant message on the dash, I topped it off and thought it was fine.
Yesterday I was checking all fluids and such and when I got to the Oil it there was grey gunk all over the dip stick and water in the oil.
There is NOT any oil in the coolant tank.
It is running fine and no smoke. I need help determining what the cause is. I am hoping it is not a head gasket and instead something like the oil cooler.
What is the best way to find out the cause of the coolant in the oil?
How do I test the Oil Cooler?
Thanks in advance.
David

[dgalvin66]

I had topped off the coolant the other day just before seeing the oil. I had to move the truck in my yard and it showed low coolant from just sitting.
Can anyone tell me how to test the different area's to determine if it is a head gasket, Oil Cooler Assembly or something else?
Thanks

[spongebob]

head gaskets are a problem with these engines, see my posts on 6.6 engine replacement and head gasket replacement costs.

[Yukon6.2]

How is the rad hose after driving it? Hard and full of preasure
I have to watch my tow trucks antifreeze
It has some treasure in the system, hard hoses.
I think it has a leaking injector cup, but that is a guess.
mine leaked at a few hoses ect till i tightened the clamps

[Kennedy]

Rarely does the Duramax put coolant in the oil, they typically pump combustion gasses into the cooling system Since yours apparently leaked into the crankcase you are probably are going to need a teardown. Once you get coolant in the oil the bearings go FAST so keep that in mind. I would convert to straight distilled water in the cooling system provided you can keep it from freezing and do a thorough flush of the crankcase until you can locate the issue

We don't typically see injector cups leaking. It could be possible to leak at the water pump shaft I guess if the weep hole is plugged.

As for injector cup leaks it seems they are quite rare and typically man made.

[More Power]

Rarely does the Duramax put coolant in the oil, they typically pump combustion gasses into the cooling system Since yours apparently leaked into the crankcase you are probably are going to need a teardown. Once you get coolant in the oil the bearings go FAST so keep that in mind. I would convert to straight distilled water in the cooling system provided you can keep it from freezing and do a thorough flush of the crankcase until you can locate the issue

We don't typically see injector cups leaking. It could be possible to leak at the water pump shaft I guess if the weep hole is plugged.

As for injector cup leaks it seems they are quite rare and typically man made.

Good advice!

The LB7's injector cups each use 2 synthetic O-rings near the top of each cup that prevent coolant from leaking into the top area of the cylinder heads where the valve springs and rocker assemblies are located. These O-rings look to be robust and up to the job. Unless they or the bores in the heads were damaged somehow during a prior dis/re-assembly, I can't imagine them leaking.

A coolant/oil leak at the oil cooler happens occasionally. You can read about them on Youtube. So, it remains a possibility for your engine' prob, but generally, a leaking oil cooler accompanies a head gasket problem brought on by chronic over-pressure in the cooling system (which also affects the water pump seals).

[dgalvin66]

So I finally did the pressure test today.
Pumped to 15 psi and it dropped by 4 psi in 10 - 15 minutes.
Could not hear any air leaking from the oil filter mount but the wind did start blowing slightly while we were out there. We did not see anything leaking.
The oil is milky and it's hard to tell if there is any oil in the coolant.
It has never blown any smoke or any loss of power.
After running the upper hose was never hard later on or following morning.
The hose has never been collapsed.

What should I check next to determine if it is the Oil Cooler or something else?
I am disabled and have a friend come over and help me to do this stuff since I can no longer do them.
I am also on a fixed income with nothing to spare so I need to be sure of problem before spending money on a repair.
If this turns out to be HG the truck is gone because there is no way I can swing that repair.
Thanks

[dgalvin66]

UPDATE
I have done several tests.
I put a glove on the radiator tank and ran the engine and it never inflated.
I checked the coolant for any gasses and there was none. These 2 tests tell me it is not a head gasket.
I did a lot more reading and research and decided it must be the water pump, I started that project yesterday and thought that I had finished today but found a large leak. It looks like I must have nicked the O-ring at the top of the bypass tube. I ordered new O-rings and will fix that next weekend,
Then I changed the water pump and removed the bypass tube I found black silicone around the top of it at the upper O-ring, so I am guessing that the shop that did the water pump years ago had a leak and did not say anything.
Has anyone used silicone at this location?

Now here is a real kick in the pants about this entire ordeal.
This all started because the coolant level dropped by over 1/2 a gallons twice and when I checked the oil the dipstick looked like milkshake on the entire length and to me it looked like the level was over full.
I drained the oil pan and there was NO coolant in it, only 2.5 gallons of very black oil.
I never noticed any type of coolant leaking, only what I believed to be the AC condensation.

I may have replaced the water pump for no reason, I did not look at the old pump to see if there were any sings of leaking at the weep hole yet.