1998 Pontiac Transport Montana
3400 V6
Done to repair = Thermostat was replaced but problem still there
tech = JK
question = Hi, I have a 1998 Pontiac transport Montana. The heat will
go from hot to cold then back from hot to cold then the temp will rise
to hot then drop down to about 60 d then to about 100/110 and the heat
will blow hot for about 5-10 min then same thing all over again i
replaced the thermostat and the problem still there any help will be
appreciated thank you
JK
Sounds as if you are getting air in the cooling system. Some common causes of
this are leaking lower intake gasket, or blown head gaskets. The rear
headgasket is prone to this condition. From under the van, the pass. side of the
rear cylinder head may show signs of leaking externally. If that is the case, it may
also be pushing compression into the cooling system. Air in the cooling system
will affect the heater in the manner you have described. You may want to let
engine run with radiator cap off and look for bubbles. Or remove the spark plugs
and inspect for signs of burning coolant.
It is possible that the replacement of the t-stat fixed the heater problem, but you
have air in the system from that procedure. This would act as if you still have the
same problem, but in fact just need to bleed system.
3400 V6
Done to repair = Thermostat was replaced but problem still there
tech = JK
question = Hi, I have a 1998 Pontiac transport Montana. The heat will
go from hot to cold then back from hot to cold then the temp will rise
to hot then drop down to about 60 d then to about 100/110 and the heat
will blow hot for about 5-10 min then same thing all over again i
replaced the thermostat and the problem still there any help will be
appreciated thank you
JK
Sounds as if you are getting air in the cooling system. Some common causes of
this are leaking lower intake gasket, or blown head gaskets. The rear
headgasket is prone to this condition. From under the van, the pass. side of the
rear cylinder head may show signs of leaking externally. If that is the case, it may
also be pushing compression into the cooling system. Air in the cooling system
will affect the heater in the manner you have described. You may want to let
engine run with radiator cap off and look for bubbles. Or remove the spark plugs
and inspect for signs of burning coolant.
It is possible that the replacement of the t-stat fixed the heater problem, but you
have air in the system from that procedure. This would act as if you still have the
same problem, but in fact just need to bleed system.
I have a1999 Pontiac sun fire that just started overheating. I replaced the thermostat and water
pump so far but it still over heats as soon as you start to drive it. The radiator doesn't seem to
get very hot and it doesn't blow warm air in the car. What do you think I should try next?
Sent from my iPad.
pump so far but it still over heats as soon as you start to drive it. The radiator doesn't seem to
get very hot and it doesn't blow warm air in the car. What do you think I should try next?
Sent from my iPad.
Answer: Sounds like a blown head gasket. When the head
gasket is broken or cracked, it will usually cause an overheat
condition very quickly once the car is started. You can remove
the spark plugs and inspect them to see if they've been
burning coolant, or look into the cylinders while the plugs are
out and see if you can see or smell coolant. The engine type in
your vehicle has been known for having head gasket problems
and warped cylinder heads. Unfortunately, you'd have to
disassemble the top half of the engine to correct this and get
the head checked out for cracks or being warped.
gasket is broken or cracked, it will usually cause an overheat
condition very quickly once the car is started. You can remove
the spark plugs and inspect them to see if they've been
burning coolant, or look into the cylinders while the plugs are
out and see if you can see or smell coolant. The engine type in
your vehicle has been known for having head gasket problems
and warped cylinder heads. Unfortunately, you'd have to
disassemble the top half of the engine to correct this and get
the head checked out for cracks or being warped.
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