1990 Buick Park Avenue

During the winter months the heater function of the automatic climate
control system will direct cold air into the passenger cabin when the
vehicle has stopped moving forward. The forward motion of the vehicle must
be stopped for 3 or 4 minutes before this happens. Once the vehicle starts
moving forward again, the climate control system will once again send heated
air into the passenger cabin.

The local Buick dealer has not been able to find the reason for this
condition. Does anyone have a suggestion where I should start looking for
the cause of this condition.

Greg Downer

maybe this is an RPM related thing and it is a worn water pump issue or
half-open thermostat.

One suggestion...
that system is vacuum operated, I believe. The cannister is under the hood
on the firewall
near the brake booster. If you should have a leak, cracked hose, etc you
might lose sufficient
vacuum that the system would be marginal.

And again, I may be way off base.

Greg Downer wrote:
> During the winter months the heater function of the automatic climate
> control system will direct cold air into the passenger cabin when the
> vehicle has stopped moving forward. The forward motion of the vehicle must
> be stopped for 3 or 4 minutes before this happens. Once the vehicle starts
> moving forward again, the climate control system will once again send heated
> air into the passenger cabin.
>
> The local Buick dealer has not been able to find the reason for this
> condition. Does anyone have a suggestion where I should start looking for
> the cause of this condition.
>
> Greg Downer
>
>

In addition to the aforementioned, check to be sure you have enough
coolant in the system. A low coolant level will also produce this
problem sometimes.

Greg Downer wrote:
>
> During the winter months the heater function of the automatic climate
> control system will direct cold air into the passenger cabin when the
> vehicle has stopped moving forward. The forward motion of the vehicle must
> be stopped for 3 or 4 minutes before this happens. Once the vehicle starts
> moving forward again, the climate control system will once again send heated
> air into the passenger cabin.
>
> The local Buick dealer has not been able to find the reason for this
> condition. Does anyone have a suggestion where I should start looking for
> the cause of this condition.
>
> Greg Downer

Sounds like it is out of coolant.
Better check the intake gaskets before the engine burns up.
And find a new dealer. The current one is incompetent.