toddk911

Yea, and it is COLD!!!!

Well, I am assuming it is electrical and probably part of the sensors or sensor/climate control but could use any advice offered.

The heat had been acting "wierd", if there is a such thing with our cars, in that when I was in neutral coasting or stopped at a light it would start blowing cool and then on accel and normal driving it would be hot again. Last night it finally did not work at all and stayed cold. Regardless of how I positioined the temp setting **** it only blew cold air.

Would this be a climate/sensor control issue?

toddk911

Ahhh hahhhh! From Clarks. But I have not messed with the cooling system for some time and how would this make the heat now go out completely???

"Intermittent Heat

"If your car's heater works fine while driving down the road but the air from the vents becomes cold at idle, you probably have air in the coolant system. Air pockets in the coolant system often accumulate in the heater core. At higher engine RPMs the coolant pump will develop enough discharge head to force some coolant through the heater core. However, at idle, the air pocket will keep coolant from flowing through the core. "

minho78

I guess Clarks is a great site.

ZW 944

Bingo! don't you love it when your solutions are straight foward?

make sure and let us know that that was your problem when you get it fixed.

mclarenno9

You may find that the reason you had heat only when you were accelerating was because your engine vacuum was close to 0 (gage). This is when the heater valve will open, allowing the hot coolant to pass through the heater core. If you have a malfunctioning vacuum solenoid (the one which sends vacuum to the heater valve) like I did, it may not be cutting off that vccuum source to the valve. My solution: disconnect the vac hose going to the valve and plug the other line with a bolt during winter. (solenoid was like 70 bucks)

The best place to start here would be to take a look at the heater valve when the car is running and you are trying to turn on the heat. Just make sure it is opening / closing when you turn the dial from colt to hot, etc.

If you get desperate you can unplug the vacuum line and you will always have heat... unless there is somehow lots of air in the system as you stated.

toddk911

Yes, Clarks is always a wealth of info!

I will bleed it for sure, but still thinking it might be the solenoid like Steve suggested as when it was giving me problems I would rotate the dial and would then seem to be ok but yesterday it did not make a difference. Also in reading Clarks as Steve mentioned it operates off vac so when driving with positive pressue it was working.

Yea, I have no problem doing the quick fix Steve. LOL Where is the vac line/plug located?

Van

And here I thought you tricked us with an aircooled car...

mclarenno9

The solenoids are just to the left of the glovebox, under the dash... I find that it is easiest to just remove the glovebox so you can see what you are doing under there.

toddk911

For now I might just unplug the vac line altogether as always heat is fine for next month for sure.

I would disconnect that from the vac reservoir? And that will not affect normal vac readings as long as I plug the vac line?

mclarenno9

You could do that, however as you can see from the diagram that vacuum source also serves another solenoid that operates the flaps within the HVAC unit (recirculation function would be my guess). There are a few options:

-Get under the dash and trace the vacuum lines... disconnect the line going to the heater valve from its solenoid and plug the inlet line (just to be safe).

-Disconnect the line in the engine bay from the top of the heater valve and plug it. This may be hard to access however...

-Unplug the vacuum line (the one with the check valve in it) going to the reservior and also into the cabin.

I would watch to see if the heater valve is actually opening/closing though when you are changing the controls. This will give you a clearer indication of where the problem really lies. You may need a helper for this.