Hello all; I need a hand with my 1994 850 turbo wagon. Bought the car a couple months ago from a customer of mine. Since then I have had a terrible time keeping coolant at the right level. It has run warm once or twice but 99% of the time she stays right at the 3 oclock position. So far I have replaced the surge tank, cap and both hoses, water pump,thermostat, radiator is fairly new. Problem I have is if I top off the coolant to say halfway between min and max and drive the car she will be fine. Did this last night and put about 30 miles of highway driving on her. Stopped to shop for a while and came out, coolant light was on for about 5 miles then went out. Temp was fine. When we stopped again I popped the hood and checked and found coolant had blown out past the cap. If I top off the coolant and check it after a drive, the level will be up but after shutting the car off, it will drop as though there is an air pocket somewhere. I have done a block check for combustion and am 99% that the head gasket is ok and she doesnt smoke other than a minute or two on cold start ups. Is there something else that could be pressurizng the coolant system? I love this car and really enjoy driving her. I just want her to cool as she is supposed to and not have to top off the tank every drive. Thanks in advance for any help and if there is any details i have left out, let me know. I tried to include everything I could think of

 

Could be a bad cap. It should hold 21 psi before venting. You'll need a cooling system pressure tester with the correct cap adapter to test it.

 

Cap and surge tank are brand new. And It did that before I changed them, but I thought maybe they had a crack.

 

I know it's brand new, but I've had brand new parts be bad right out of the box.

But if it was doing that before, I don't think it is your problem.

Is the fan working?

 

Yes the fan is working, I forgot to mention that. I have talked to numerous techs and watched a few videos and it seems that the head gaskets can leak on these and still show ok on a block test. They will also run good while doing it. So im thinking thats what is pressurizing the coolant. Gonna have a conversation with the guy I bought the car from to see if we cant work something out.

 

A block test you're referring to is the ones with the color changing fluid, correct?

 

yes sir. The fluid is supposed to go yellow if its bad and I had no change in color.

 

I really have not seen a car with a bad head gasket not come up positive on that test, to be honest.

Another option would be pressure test the cooling system and use an inspection camera in the cylinders to check for leaks.

Or, pressurize the cylinders with a cylinder leakage tester and watch for bubbles in the reservoir.

 

I agree with Wood. You need to test for a blown head gasket.

NAPA AUTO PARTS

 

Sounds like a bad head gasket to me.