Expert: Rob Painter - 2/27/2011

Question
I HAVE DONE ALL THOSE THINGS TO MY 97 ELDO4.6,AND STILL LOSING COOLANT ,BUT I THOUGHT THE FANS WERE SUPPOSED TO WORK EVEN WITH THE KEY OFF IF ENGINE IS HOT,ARE THEY SUPPOSED TO WORK LIKE THAT

Answer
Hello,

I will tell you right now, you have MAJOR problems with that finely engineered Aluminum engine that CANNOT be over heated for even seconds before it self destructs. Chances are that the engine is going to cost big dollars to repair. Far more than the car is worth.

Please look in my archives. In fact, just the other day I answered a question in which the person was told they need a head gasket-a very expensive repair.

Worrying about the fans to come on with the key off is the least of your problems. It's too late and I will give you some ideas where to look for the coolant leak is and this is where to costly comes from. Chances are you have one or two blown head gaskets. This is not the original problem, but is an after effect to and original over heating problem. This is not like the iron duke that can over heat in which the fans to cool the engine, with the key off. The key words in this example is Iron Duke--a cast iron engine in which it takes excessive over heating before major engine damage is done.


Have you ever seen what happens to an aluminum can when thrown into a fire? If you haven't try it once. This is your aluminum engine over heating. Things begin to melt or destruct almost instantly!

At minimum, without even looking at it and only from your description, you coolant leak is a head, a head gasket or times two, or even a cracked engine block. Over heating and coolant leakage go hand and hand with major damage on this aluminum engine. Can't go with a used engine at the junk yard because it most likely have the same damage. Very common problem. People figure they can over heat this engine and have no consequence.

I will tell you its not worth fixing. To replace head gaskets, you could be looking at an easy $1,200-$1,500 for two. Then you need to find out and fix the over heating problem immediately and it could be a radiator, fans not working right, plugged cooling system, who knows?

If you don't fix the over heating problem, you will blow the head gaskets again. A new GM engine will run you $5k installed and you still have to fix the original problem.

Obviously, I have no agenda. I am not fixing the car. I am just telling you the facts. No cheap repair! Its a Pandora's box!

To confirm what I am telling you, the radiator can be filled and a radiator pressure tester can be used. Pump to 15 pounds and watch the gauge go down. Your leak should be obvious if external from the head down the block on either of both sides. Then you can take the pressure gauge off and if you saw nothing leaking externally, then check the engine oil. If milky colored, you have a blown head gasket. If not there, start the engine and look at the exhaust. If white, blown head gasket. That's your coolant leak.

I have worked on these aluminum engines since 1982 when they first came out and in all that time, if this style engine over heats for seconds, not minutes, it's toast!

So much for worrying about fan operation.






You say you have a coolant leak.