1985.1 944

My heater (the heat itself not the blower motor) only seems to push hot air out whilst the rpms are 3000 or more. Or if I turn the fan off and let the car idle normally then turn the fan back on full it blows hot for about 7 seconds. Otherwise it blows cold. Any suggestions?

VirginiaF1

http://www.clarks-garage.com/shop-manual/hvac-01.htm

Howdy..
Let me spare the forum veterans some keystrokes here..

See last paragraph at bottom of page url listed above.

Let us know if that solution has a positive effect..
Glwr
Mikey

Bb

V2Rocket

id make sure the heater valve was opening all the way, the heater is probably the most reliable part of the car!

mytrplseven

Air in the cooling system causing air gaps at certain RPM?

william_b_noble

check vac lines to dash from engine and to heater valve

1985.1 944

Where is the heater valve? And which vacuum lines? Also not sure if its relevant but the cowl is not there. The car didn't come with one so I'm wondering if cold air is getting sucked thru the exposed blower motor? The motor has a cover on it but the part from the windshield going to the blower motor and battery stuff is exposed. Also I noticed the heat comes thru when the fan isn't on.

VirginiaF1

Hi again..
Do you have access to the internet?

If so, click here and read this page:
http://www.clarks-garage.com/shop-manual/hvac-01.htm

konakat

I just worked on my early heater core. I would bleed your coolant system to start, then make sure the heater valve cable is still attached and working correctly. I would think you would notice if the heat slider was loose, so I'm guessing it's air in your coolant system.

V2Rocket

heater valve is at the back of the engine in the middle, black plastic mushroom looking thing with a white arm and a cable attached to it