Crank No Start

timing-belts
gaskets

#1

About a week ago my car died when pulling out of a parking lot. The engine just seemed to die. I had it towed to a shop. They diagnosed the problem to be blown head gaskets. The total bill will be about 1800.



This is a '95 Dodge Intrepid, Dual Cam 3.5 liter V6. Silver



The symptoms they found were:

No compression on one side of the engine, Low compression in 1 cylinder on the other side of the engine and 85 psi on the other two cylinders.



The problem I have with this diagnosis is that the car had been running fine until it stopped. It had not overheated. I had just pulled out of a parking spot drove 100 ft and the engine died.



I have convinced myself that the real problem is valve timing. Something happened and the cam slipped. I think I can explain all of the symptoms with this explanation.



Finally, the question(s). Am I nuts? Could valve timing actually do this? If it’s the head(s) I’m just going to have it towed away and junked because the repair will cost more than I could replace the car for. But if its valve timing I could get that fixed for much less money.



Or, could something else cause these symptoms?


#2

I’m not 100% sure on this, but I think this engine is an interference engine which means that if a timing belt breaks some valve damage will occur when the valves quit moving and the pistons don’t. This leads to the intake valves hitting the pistons and bending one or more of them to some degree.

It’s not likely the head gaskets are the problem at all considering no overheating and problems exist on both banks, although head gaskets will have to be replaced if the cylinder heads are repaired.
Checking the engine for damaged valves is very simple and should be done before wasting time on a compression test and the blown head gasket diagnosis not correct IMHO.

If this engine is a non-interference (or free-wheeling) type then a new timing belt/tensioner setup should fix this; BUT, I’m reasonably sure it’s not a free-wheeler and that means valve damage.
The compression stats you mention point to bent valves on an interference engine (unlucky you) or valves static in their holes on a free-wheeler (lucky you). I think you fall into the former category though.


#3

Thanks for the reply. I just checked out a number of web sites and I guess there is some disagreement whether the 3.5 is an interference engine or not. Chrysler lists it as interference but I found at least 20 postings that say that it really isn’t…maybe I got lucky. Thanks for the input. I had the car towed home today and will check it out tomorrow.


#4

The 3.5 is an interference motor as OK4450 mentioned. That being said I put a timing belt and tensioner in one a few weeks ago. The belt had broken at low speed as the owner was parking. I warned him of the possibility of valve damage but he wanted to try the belt before junking the car. Car ran perfect after belt change. Might be worth throwing on a belt and see if it runs.
~Michael


#5

At 12 years old, your car’s average mileage would be about 150,000 miles. The timing belt in your car is probably original with 150,000 miles on it … WAY too long. /// The valves can be tested for seating qualities. Using a leak-down-tester, the mechanic turns the camshaft, with a wrench, for testing each cylinder’s air-pressure holding ability. If ALL cylinders hold air pressure fairly well, the valves are NOT bent. Therefore, it wouldn’t be neccessary to put a timing belt on when you can test it so much more easily with a leakdown test.