1998 Pontiac Grand Am gt 3.1
v6
GM tech = KK
question = my 98 grand am has no heat. The gauge on the dash works.
The engine gets hot, and the car has not over heated. Is my problem the
thermostat or the heater core?
KK:
Several things can cause a no heat condition.
Assuming the coolant is full, there could be air pockets in the cooling system-
this engine is prone to having leaking intake manifold gaskets, and/or blown
headgaskets. Either can make air pockets in the cooling system, and the
heater core cannot transfer heat from an air pocket into the interior. Will not
necessarily overheat.
Possibly a plugged heater core not allowing coolant to flow through it.
Possibly a temp. door problem in the dash not directing air over the heater
core.
A bad thermostat will usually either cause an overheating, or an engine that will
not get up to proper operating temp. If the coolant temp is lower than normal,
then would suspect a stuck open thermostat.
v6
GM tech = KK
question = my 98 grand am has no heat. The gauge on the dash works.
The engine gets hot, and the car has not over heated. Is my problem the
thermostat or the heater core?
KK:
Several things can cause a no heat condition.
Assuming the coolant is full, there could be air pockets in the cooling system-
this engine is prone to having leaking intake manifold gaskets, and/or blown
headgaskets. Either can make air pockets in the cooling system, and the
heater core cannot transfer heat from an air pocket into the interior. Will not
necessarily overheat.
Possibly a plugged heater core not allowing coolant to flow through it.
Possibly a temp. door problem in the dash not directing air over the heater
core.
A bad thermostat will usually either cause an overheating, or an engine that will
not get up to proper operating temp. If the coolant temp is lower than normal,
then would suspect a stuck open thermostat.
Other questions
Problem with my 2002 Pontiac Grand Am
2.2 Votec
GM tech = JK
question = Just bought the car from my sister. Says the following has happened
for years.
The blower motor comes on while the engine is off every hour or so. Runs for
about 10 seconds. Never causes a low battery situation. Doesn't seem to be
normal, but I guess it could be to prevent a/c odor smell from mildew. Didn't see
anything about it being a feature of the car in the owner's manual. Is it normal?
JK:
Yep, you got it exactly. It is to help dry the evaporator coil and case to prevent
mold and mildew. It is called "Afterblow". Not all models have this feature.
Normally on models being built to ship to warmer states. GM even has a kit that
can be installed on vehicles that were built without this feature.
2.2 Votec
GM tech = JK
question = Just bought the car from my sister. Says the following has happened
for years.
The blower motor comes on while the engine is off every hour or so. Runs for
about 10 seconds. Never causes a low battery situation. Doesn't seem to be
normal, but I guess it could be to prevent a/c odor smell from mildew. Didn't see
anything about it being a feature of the car in the owner's manual. Is it normal?
JK:
Yep, you got it exactly. It is to help dry the evaporator coil and case to prevent
mold and mildew. It is called "Afterblow". Not all models have this feature.
Normally on models being built to ship to warmer states. GM even has a kit that
can be installed on vehicles that were built without this feature.
Other related articles:
