My wife was driving my 2000 C4 Cab (50,000 miles) on Thursday when the temperature light started flashing. Had her turn the car off and turn it back on, no flashing light so she drove it home. On Sauturday I went to drive the car and the light was flashing again. checked the coolant tank, empty except for some "mayonaisse), then the oil, looks like chocolage milk.

I guess it is my turn. So how do you determine if it is a head gasket failure (I should be so lucky) or a cracked cylinder liner? Is there an easy way to differentiate?

The worst is that I had an extended warranty, but it ran out last January. Too bad it did not happen a year ago.

 

It may not be either.....the walls where the coolant run are next to the oil channels in the block. Over time the coolant eats away at the walls and the walls between the coolant and oil wear down and then oil and coolant begin mixing together inside the walls of the engine block...its called intermix. VERY hard to find exactly where it is happening and very hard to fix. If it's an intermix problem, you should get a reman 3.4L. To my knowledge they fixed this issue on the 3.6L and the reman. 3.4L engines. Happened to mine. You will get no warning of the problem other than the low coolant warning which is your flashing temp gauge. I got the flashing temp gauge for a few months then noticed some gunk in the coolant tank. Dealer replaced my engine as the car was under warranty at 75k miles. If it was a cracked cylinder, it would not run very well...and if it was a head gasket, it would likely be losing power on one or a few cylinders....if the car feels fine, then I would bet its an intermix issue.....