Expert: Rob Painter - 6/9/2011

Question
I have changed the water pump, radiator, thermostat but car still overheats what could be the problem. I have checked the head gaskets if that's not it what could it be. please help!!!

Answer
Hello,

That is kind of an open question on this poorly designed aluminum engine. Any kind of restriction in these small water jackets could cause troubles. All too often old gasket material is inadvertently left inside the engine, which restricts flow. I have seen this often, whether from the thermostat or the water pump.

Now, you did not give me the year make or model.

Are the coolant fans coming on? If not, car will overheat at city speeds. With engine off, turn ignition on. Put in A/C mode or defroster. Fans should come on in about a minute.

Don't know how you checked head gaskets.

When warmed up, are upper and lower hoses the same temp? If not, you have a circulation issue in the block.

Heads or gaskets have 3 different ways to leak. External. Internal where the coolant goes into the oil. The third way is through the combustion chamber and white smoke will come out of the exhaust.

These engines cannot take any type of heat. Aluminum begins to melt when it is overheating. This engine and when I say that, I mean aluminum in all displacements is great on mileage and quick, but notorious for overheating issues. I have 3 more questions on over heating Cadillac engines.

Cadillac design on this engine sucked. They knew they had these issues and instead would rip the consumer off when they drove the engine hot either by selling parts or engines for billions of dollars. I thought it would have been a good idea to put a bright orange warning label affixed to the dash warning people.

It is unbelievable as to just how many people destroy these engines by running the engine hot like the old cast iron Chevys.

A good used engine is not available. They have all been overheated in the junk yards.

I have mentioned before even AMC/Renault Alliance built a better engine. At least it could be serviced. A piston and liner kit was available and the cost to repair an overheated engine was dramatically less.

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