no interior heat

[Zigmont M.]

I do not have any heat in the car. Not quite sure what to look for first. the heater control valve was replaced last year. Is it a vacuum problem either on valve or on vacuum switch or is it the switch?

[Scott S.]

Re: no interior heat

Zigmont, Have you checked your coolant level? Are your heater hoses hot on both sides?
At -28 Celsius, it would be a problem here today!
Scott

[Zigmont M.]

Re: no interior heat

Assuming coolant level is fine because engine temp is normal when driving but will check to be safe. Don't drive in the winter but would be nice to have heat on fall drives. Now is the time for me to fix all my little problems.

[Harry S.]

Re: no interior heat

Zigmont, essentially all the C2 A/C cars operate the same when it comes to heat. The vacuum starts at the back of the carb. The vacuum hose then splits and the part/hose that controls heat goes through the firewall to a vacuum switch that is mounted on top of the interior heater box behind the glove box. When you pull the upper right lever for heat a cable goes to the switch on the interior heater box and opens the vacuum switch. This hose goes through the firewall again to the hot water shut-off valve. When the switch opens it allow vacuum to flow to the hot water shut-off valve. The hot water shut-off valve then opens and allow hot water into the interior heater core.

I'd pull the hose off the hot water shut-off and pull the heat lever. If you have vacuum at the hot water shut-off end then the problem is the valve. If there is no vacuum start backing up the line and look for a leak. Bad switch on top of interior heater box, crack in a hose or a vacuum hose fell off somewhere.

If you are using R12 Freon I suggest you start the car every two weeks. When the engine gets to temp. turn on the A/C to move the freon around. Check the temp. of the cold air, it should be about 20 degrees below ambient.

Good Luck

[Zigmont M.]

Re: no interior heat

Zigmont, essentially all the C2 A/C cars operate the same when it comes to heat. The vacuum starts at the back of the carb. The vacuum hose then splits and the part/hose that controls heat goes through the firewall to a vacuum switch that is mounted on top of the interior heater box behind the glove box. When you pull the upper right lever for heat a cable goes to the switch on the interior heater box and opens the vacuum switch. This hose goes through the firewall again to the hot water shut-off valve. When the switch opens it allow vacuum to flow to the hot water shut-off valve. The hot water shut-off valve then opens and allow hot water into the interior heater core.

I'd pull the hose off the hot water shut-off and pull the heat lever. If you have vacuum at the hot water shut-off end then the problem is the valve. If there is no vacuum start backing up the line and look for a leak. Bad switch on top of interior heater box, crack in a hose or a vacuum hose fell off somewhere.

If you are using R12 Freon I suggest you start the car every two weeks. When the engine gets to temp. turn on the A/C to move the freon around. Check the temp. of the cold air, it should be about 20 degrees below ambient.

Good Luck

The ac doesn't need to be in working order for the heat to work does it?

[Harry S.]

Re: no interior heat

The ac doesn't need to be in working order for the heat to work does it?

Nope. In a non-A/C car there is hot water in the heater core all the time. In an A/C car there is only hot water in the heater core when you pull that upper right lever.

I was just describing how it works in an A/C car.

[Harry S.]

Re: no interior heat

Curious, any progress?

[Zigmont M.]

Re: no interior heat

No not yet. I do not keep the car at my house and i'm in the middle of fixing other minor issues with the car first. I'll let you know when I start digging into it. Really thinking it will be vacuum related since I have other vacuum related problems but will find out.