ol55

I went for a ride and I have no heat. Blower motor works. Can I just put a mytyvac tester on the vaccuum actuated water **** (shop manual term) to see if it opens?

Thanks,
Larry

rogerz

unlikely that is the problem it is a very simple disc valve. you can operate it by hand. look at the little lever you can see at the bottom. if it is down the valve is open. more likely the vacuum lines are shot. diagram in the fsm. one comes from the plenum to the vacuum tank one goes to the water valve and the last one goes into the cabin. the big one is for the cruise control. vacuum closes the water valve

NismoPick

Did you check the coolant level?

If the coolant level is too low, it won't make it to the heater core.

ken99

Slipping fan belt?

Hpjc10

The way it works is this: when your car is cold, coolant does not flow past the thermostat until it warms uo, therefore any blowing air will be cold. Once the car is warm, it flows to the vaccuum actuated stopcock which is a simple valve that gets sucked closed by vacuum when activated. Down means water is flowing into the heater core, up means its closed.

Are you getting any air from your vents at all? Is it coming from just the defogger vents. If so you have a vacuum problem.

If you can change where the air comes from (head/feet, etc) then vacuum is fine. Check to see if the valve is stuck closed, its right up near the battery above the egr solenoid. If it is just pull on the lever under the device and bring it to its lowest position. It should stay there when the car is running and the temp switch is in the hottest position unless your vacuum canister has a problem.


Worst case scenario, you have a clogged hearer core which isnt letting any hot water in. In this case you need to remove the dash to replace.

ol55

Started by filling up the coolant level from the radiator cap. The fill bottle was at the at the right level but refilling from the cap has given me heat for now.

Thanks for all the posts!

Larry

ken99

Double check the rubber tube connecting the radiator to the overflow bottle. If not connected or if it has cracks in it, any hot coolant pushed out by the system will be lost. When the system cools, it will suck back in air instead of coolant.

ol55

I'll check it. If that is the case then wouldn't the reservoir be empty?


Thanks!

ken99

Depends on where on the tube the leak occurs.

rogerz

happened on my 85. first of all it is an expansion tank not overflow. the tube was kinked and wouldn't allow flow either direction so the tank stayed full and the pressure cap let the excess blow out on the ground. Had to keep filling thru the cap til I figured it out. Be sure the tube is clear (blow thru it). keep tank level correct and check the level at the radiator cap. Fill as necessary. The VG30 seems to have air pockets that need to work themselves out. Just put a new rad in my 86. Had to add fluid 2-3 times thru the cap because when she cooled down the liquid in the expansion tank got sucked into the engine. Other 31 owners I know have had the same experience. You could also take the top off the water valve and fill until it runs out that seems to eliminate trapped air but I had no problem just topping off. Cool here in Seattle tho.

ol55

This sounds like the problem. Too cold now but will check when it gets a little warmer...

Thanks,
Larry