What does your engine temp gauge say? Is your antifreeze at the proper level? Did you try bleeding air out of the engine? You might have to flush the heater core if you already checked these possable problems.
Is your heater core bypass valve working correctly? You can eliminate it all together and have the coolant run through the core all the time. There is a flap in the dash that closes it off from the rest of the system so it won't interfere with your A/C in the summer.
Try feeling the hoses on both sides of the bypass valve with the car warm and see if the coolant is in fact flowing through there.
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1990 Firebird 3.1
T04E 46 trim turbo, Front mount intercooler,
38mm Wastegate, 1.6 roller rockers
Dynomax cat-back, 24# injectors, HKS BOV Click here to see a pictoral
3.4/3500 hybrid under construction
Linear Mode
