I have a 2003 Forester 2.5 litre. The heater core leaked at 50K miles and was replaced by a dealer. Now it is leaking again at 84K miles! Any possibility that both heater core leaks have been caused by a head gasket leak?

I have heard of problems with blown heads gaskets on the 2.5, so I am suspicious. But the car has never over heated and otherwise runs like it is supposed to. I have followed the proper maintenance, no accidents and I have owned since new. Apparently a leaking heater core is very rare for a car this young and 2 leaking cores due to defective parts seems improbable.

Any thoughts?

Cheers!

 

It's certainly worth having a coolant contamination check done to see if there are any exhaust gasses leaking into the coolant due to head gasket problem. Its a simple test which will take half hour or so and involves a bit of kit which is attached to the coolant system and some liquid which changes colour if exhaust gasses are detected.

 

It's possible the 2nd core was damaged during replacement- end tanks are only plastic so rough handling may have weakened it, causing it to fail prematurely.

How old is the new core? If it was done by a main dealer then the replacment should be warranteed for 12months.

Coolant over-pressurisation can cause one to fail. This can be caused by both a head gasket or faulty coolant cap. So worth checking it out.

Second thing to note, I take it it definetlyis losing coolant? ; as a common occurance when the heater box has been messed with it could be leaking a/c condensate or rainwater from the intake scuttle instead. Either way with the latter you get damp footwells and steamed up windows, just you don't lose any coolant.

 

Thanks for the replys. It has been 15 months and 20K miles since the first heater core replacement. There is a coolant smell coming from the airvents and the windshield fogs on the driver side with a greasy film. I took it back to the same dealer that replaced the first heater core and they agree the heater core failed again. Dealer is not offering any discount since I am outside the 12 months warranty. They gave me a US$1,000 quote to replace it again.

Will a pressure test detect a *slightly* leaking head gasket? Any possibility the head gasket could be leaking for 30K miles with no other effects? Any way to determine if the heater core was damaged by the installer or not installed properly by the dealer?

 

It's not a pressure test I mentioned, but a contamination test. It uses a liquid which has a chemical reaction when any hydrocarbons are present in the coolant.