Slick 60's

I have seen heater cores flow great that have a "coating" of corrosion in the coolant passages that prevents the heat from transferring from the coolant to the copper or aluminum. It is not that uncommon. just a thought.

Pugs

charliemccraney wrote: How do you know the valve is working? I didn't understand that part.

the inlet hose is hot on both sides of the valve. i have the deluxe heater and the valve is on the inner fender with a piece of hose on either side of the valve. both are hot.

i really appreciate all the responses so far guys.

Puglsy is right - it might be flowing but coated with grime and corrosion that is causing a drop in efficiency. My heat isn't nearly as warm as it should be and is exhibiting similar symptoms. I'm in GA, though so it's not quite cold enough to make a huge difference.

If:
-It used to heat better than it does now
-There is heated coolant going in and heated coolant coming out
-The valve is working

Then it's time to reach in there and check the core to see if it's radiating heat. If it is then you might have some seals leaking in the vent system somewhere. Or you have that rat's nest.

I'm lucky that it's mild down in GA - I can wait until i revamp the entire system (some P.O. did a strange job of it somewhere down the line) to replace/diagnose mine. With that said, I'm kind of anxious to see what you turn up!

Jim

Install a 195 tstat. A 180 is a summer(southern) tstat.
Make sure you purge the air from the heater core.
Drill a 1/8" hole in the flat part of the tstat.(helps with purging system.)
Just my 2 cents. Good luck.

I replaced the core on mine this past summer and it made a HUGE difference in the heat output....was nearly as cheap as refurbishing/cleaning the old one.