77BlueL82

It was 12deg. this morning when I started the car today. Just let it warm up. Got nice n' tostie inside, so I decided to take it to work in NYC (35 mile run). Doing 65MPH on Rte78, about half way no more heat, just cold air. Slowed down at the Holland Tunnel the heat came back. Going home the same thing happened in reverse, no heat till I got near home. Did anyone have a problem like this?

PS Caught the Rat that ate up my tunnel/transmission colar. Got stuck on a sticky pad. :smash: :smash: :smash:

Denney

If you have a/c, the problem could be with the heater diverter valve (which is operated via vacuum). Slowing down (coasting) may have resulted in sufficient manifold vacuum to kick the valve back on, but when accelerating the vacuum signal could have dropped enough to close the valve. If you don't have a/c, I would then suspect perhaps a clogged heater core... If you do have a/c, you could bypass the valve and see if that fixes the problem (then check the vacuum line to the valve for splits and vacuum levels). If the vacuum is ok on the line, then I would get a new valve. :seeya

Jvette73

Check the coolant level in the rad. Low coolant level can cause what you describe.

GaryS

That would be my first thought. I have had this happen on three different cars and each time it was low coolant. Now, why did I have low coolant. One car had a weeping side tank on the radiator (new readiator), another car had a weeping water pump (new pump) and the third car is my daughter's and she wouldn't think to put gas in it is she didn't need to.
Gary