frickenbored

So I'm looking at my dads 2001 Dodge 2500 with a 5.9L v8 with 40,000 miles. I noticed that the coolant overflow tank has a thin (4-5mm) layer of engine oil sitting on top of the coolant. So I checked the engine dip stick and I didn't find anything unusual. Oil was dark brown, didn't look like a milkshake. So then I ran the engine to churn the oil up to see if the water would create bubbles and to see if coolant was being burned in the exhaust.

The exhaust was clear and the oil didn't have any bubbles in it at all.

I'm still thinking its a head gasket because last winter the water pump went out and my dad drove that truck about 30 miles with the temp gauge in the red zone. So I'm thinking that one or both of the heads got warped since the engine only has 40,000 miles. Does anyone have any thoughts on this?

MDTAHOE

Is it auto trans? Could be the trans cooler is broken inside the radiator. What is the trans fluid level?

frickenbored

oh I forgot to mention that it has a towing package so it has a external trans cooler and it does not go through the radiator.

2wd-K5

try a compression test on it

MDTAHOE

Sometimes they run the trans fluid into the rad then to an external cooler. Does it have an oil cooler in the rad?

frickenbored

no oil cooler in the rad. I think i'm going to pressure test the system. I'm told that if you hook a cooling pressure tester to to rad and then run the engine untill the thermostat open you can tell if there is a head gasket leak between the cylinder and water jacket because the cooling system pressure will spike everytime that cylinder goes through the compression stroke.

RacerX

Maybe, but its more likely you ll break your $120 Coolant System Pressure Tester. You should run the engine while the pressure tester is on the radiator. Its easier to just pump up the system and see how long it maintains pressure. If you pump it up to 18psi and it doesnt hold you have a leak. If it does isnt dripping on the ground then its leaking internally. Simple as hot coffee.

frickenbored

true but I figured that it would be more definitive if I saw huge pressure on the gauge while the engine is running because an internal leak could also be from an intake manifold gasket. Plus this is actually the way that chrysler's dealerconnect (chryslers own service information) says to test it. I'm about 90% sure its a head gasket because when the thermostat opens the coolant hoses get really hard, harder than normal which is telling me that the pressure is to high which is pointing towards compression pressure getting into the cooling system.

Im really just stalling to fix this thing, I'm a heavy tech at a chrysler dealer, but I was wondering what other people had to say about this and see if maybe anyone has run into this and it wasn't a head gasket. I just have a really bad feeling that those heads are warped.

And yes I know, I'm fixing cars for the enemy.

RacerX

I dont know man, I dont think so. If you did a compression test and even if you got 70psi on the left side head that is still more than enough pressure to push against a 13-16psi radiator cap. My point is that if the head gasket is bad there should be bubbling in the overflow tank. Easiest way to check is does the car overheat? The coolant has to be going somewhere. Schmutz in the overflow tank isnt really indicative of a head gasket. It could just be grime that had been in the coolant system for a long while.

MDTAHOE

I would have to agree