pete88gt

Hey everyone, it's beginning to get pretty cool here in the mornings so I've decided to get my heat working again. My blower motor is working without issue on all speeds. When I move the selector switch that directs airflow I do not hear any hissing to indicate a vacuum leak. Replaced the thermostat properly about 2 weeks ago. Heater hoses are hooked up properly. The heater core is not leaking. Replaced the temp sensor on the heater lines near the thermostat as well. I'm out of ideas, but I can tell you that when I cycle the airflow switch I only ever het air coming out of the defrost vents...I don't know how to correct this problem though.

PRO50SC

Are the heater hoses getting hot on both sides of the core? Air pockets in the system? Clogged heater core?

88GTBLACK

Did you bleed the air out of your coolant lines? Is there any coolant leaks anywhere else in the car?

pete88gt

no, there are absolutely no coolant leaks anywhere, the heater core was replaced just before I purchased it about 2yrs ago (not to say it couldn't be clogged). Both sides of the heater hoses are getting hot, but it's fairly difficult to differentiate between engine heat on the hoses or actual coolant heat...yes I flushed the coolant system at my shop when i replaced the thermostat and bled the system properly...

mattdel

1991roush

sounds like you have a cloged heater core, I had the same problem last year, I replace it with a new one, now is working great, make sure if u replace it get a good quality heater core u don't want to do the job twice couple months later

mattdel

Heater core failure is almost always attributed to electrolysis, not the brand name of the core.

Stick a volt meter in your coolant. If you read anything over .3v, flush the system completely and add a couple more grounds to your block. Problem solved.

pete88gt

I did a reverse flush on the heater core today at work, and some gritty **** came out. I hooked the hoses back up and a good bit of heat came out of the vents and the return side hose started to get warm. I then flushed from inlet to return again and it broke up some more crap. I let it get back to operating temp and checked the hoses again, both were real close to equal temp which tells me there may be some more **** in the core, but it's fine for now. At least I able to unclog it and get HEAT!!