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Where's the thermostat on my '97 Pontiac Montana Transport. Is it hard to get to?
- Thread starter Tom
- Start date
Christopher
New member
That should have a 3.8L v6 and it is located below the throttle-body on the left/drivers side of the engine. Follow the upper radiator hose to it. It can be a pain to change.
What makes you think it's a thermostat problem? I wouldn't want to change it unless I was 100% sure that is what the problem is.
This engines upper intake plenum is prone to getting an internal crack in the composite plastic. When this happens coolant will get dumped into the intake. The amount depends on how badly it is cracked. This can be checked by removing the air inlet tube going to the TB. Open the throttle plate and with a flashlight inspect the inside of the plenum. It there is any coolant leakage it will be visible about 2 inches in from where the TB mounts to the plastic plenum. This part costs about 150 bucks and takes about 6 hours to replace.
An air pocket in the coolant system can also cause a thermostat not to open. This is because the thermostat has to be submerged in fluid to operate properly. It will not sense air temperature.
Your vehicle requires Dex-cool anti freeze that is generally twice the cost of regular green anti freeze. No you can not mix the two, they are totally different products.
Before removing and replacing the thermostat attempt purging the air out of the system. This can be done by parting the vehicle on an incline or jacking up the front. This positions the radiator fill higher then the thermostat housing. With the vehicle off, remove the radiator cap and top off the coolant.
What ever you do, do not run the vehicle with the rad.cap off. Some one could get seriously injured.
After topping off, you will notice bubbled in the filler neck. As the level slowly lowers, top off again. This may take several tries. Once no more bubbles are present, Place your left palm over the filler neck, sealing the radiator. With your right hand squeeze the upper hose and release, do this a couple times before checking the fluid level. Add a splash more and continue. This may take a few times, before no more air bubbles are visible. Put on the cap and start the vehicle. Turn off all accessories including the heater and the fan. As the gage starts to increase temp. to over 1/4 turn on the heater, not defrost, and set the fan speed on low. This will open the heater control valve and allow coolant to flow through the heater core forcing out any air. At just over 1/2 the thermostat should open and the gage reading should drop slightly. Just under 3/4 the coolant fan should kick on and cycle, this will drop the gage reading down around 1/2. once the fan shuts off. Turn off the heater and the engine, lower the vehicle. You have purged the coolant system. Make sure to fill the overflow bottle to about 3/4. This will allow coolant to be drawn back into the radiator as the engine cools.
Hope this helps with diagnosing the problem. Christopher
What makes you think it's a thermostat problem? I wouldn't want to change it unless I was 100% sure that is what the problem is.
This engines upper intake plenum is prone to getting an internal crack in the composite plastic. When this happens coolant will get dumped into the intake. The amount depends on how badly it is cracked. This can be checked by removing the air inlet tube going to the TB. Open the throttle plate and with a flashlight inspect the inside of the plenum. It there is any coolant leakage it will be visible about 2 inches in from where the TB mounts to the plastic plenum. This part costs about 150 bucks and takes about 6 hours to replace.
An air pocket in the coolant system can also cause a thermostat not to open. This is because the thermostat has to be submerged in fluid to operate properly. It will not sense air temperature.
Your vehicle requires Dex-cool anti freeze that is generally twice the cost of regular green anti freeze. No you can not mix the two, they are totally different products.
Before removing and replacing the thermostat attempt purging the air out of the system. This can be done by parting the vehicle on an incline or jacking up the front. This positions the radiator fill higher then the thermostat housing. With the vehicle off, remove the radiator cap and top off the coolant.
What ever you do, do not run the vehicle with the rad.cap off. Some one could get seriously injured.
After topping off, you will notice bubbled in the filler neck. As the level slowly lowers, top off again. This may take several tries. Once no more bubbles are present, Place your left palm over the filler neck, sealing the radiator. With your right hand squeeze the upper hose and release, do this a couple times before checking the fluid level. Add a splash more and continue. This may take a few times, before no more air bubbles are visible. Put on the cap and start the vehicle. Turn off all accessories including the heater and the fan. As the gage starts to increase temp. to over 1/4 turn on the heater, not defrost, and set the fan speed on low. This will open the heater control valve and allow coolant to flow through the heater core forcing out any air. At just over 1/2 the thermostat should open and the gage reading should drop slightly. Just under 3/4 the coolant fan should kick on and cycle, this will drop the gage reading down around 1/2. once the fan shuts off. Turn off the heater and the engine, lower the vehicle. You have purged the coolant system. Make sure to fill the overflow bottle to about 3/4. This will allow coolant to be drawn back into the radiator as the engine cools.
Hope this helps with diagnosing the problem. Christopher
Christopher
New member
That should have a 3.8L v6 and it is located below the throttle-body on the left/drivers side of the engine. Follow the upper radiator hose to it. It can be a pain to change.
What makes you think it's a thermostat problem? I wouldn't want to change it unless I was 100% sure that is what the problem is.
This engines upper intake plenum is prone to getting an internal crack in the composite plastic. When this happens coolant will get dumped into the intake. The amount depends on how badly it is cracked. This can be checked by removing the air inlet tube going to the TB. Open the throttle plate and with a flashlight inspect the inside of the plenum. It there is any coolant leakage it will be visible about 2 inches in from where the TB mounts to the plastic plenum. This part costs about 150 bucks and takes about 6 hours to replace.
An air pocket in the coolant system can also cause a thermostat not to open. This is because the thermostat has to be submerged in fluid to operate properly. It will not sense air temperature.
Your vehicle requires Dex-cool anti freeze that is generally twice the cost of regular green anti freeze. No you can not mix the two, they are totally different products.
Before removing and replacing the thermostat attempt purging the air out of the system. This can be done by parting the vehicle on an incline or jacking up the front. This positions the radiator fill higher then the thermostat housing. With the vehicle off, remove the radiator cap and top off the coolant.
What ever you do, do not run the vehicle with the rad.cap off. Some one could get seriously injured.
After topping off, you will notice bubbled in the filler neck. As the level slowly lowers, top off again. This may take several tries. Once no more bubbles are present, Place your left palm over the filler neck, sealing the radiator. With your right hand squeeze the upper hose and release, do this a couple times before checking the fluid level. Add a splash more and continue. This may take a few times, before no more air bubbles are visible. Put on the cap and start the vehicle. Turn off all accessories including the heater and the fan. As the gage starts to increase temp. to over 1/4 turn on the heater, not defrost, and set the fan speed on low. This will open the heater control valve and allow coolant to flow through the heater core forcing out any air. At just over 1/2 the thermostat should open and the gage reading should drop slightly. Just under 3/4 the coolant fan should kick on and cycle, this will drop the gage reading down around 1/2. once the fan shuts off. Turn off the heater and the engine, lower the vehicle. You have purged the coolant system. Make sure to fill the overflow bottle to about 3/4. This will allow coolant to be drawn back into the radiator as the engine cools.
Hope this helps with diagnosing the problem. Christopher
What makes you think it's a thermostat problem? I wouldn't want to change it unless I was 100% sure that is what the problem is.
This engines upper intake plenum is prone to getting an internal crack in the composite plastic. When this happens coolant will get dumped into the intake. The amount depends on how badly it is cracked. This can be checked by removing the air inlet tube going to the TB. Open the throttle plate and with a flashlight inspect the inside of the plenum. It there is any coolant leakage it will be visible about 2 inches in from where the TB mounts to the plastic plenum. This part costs about 150 bucks and takes about 6 hours to replace.
An air pocket in the coolant system can also cause a thermostat not to open. This is because the thermostat has to be submerged in fluid to operate properly. It will not sense air temperature.
Your vehicle requires Dex-cool anti freeze that is generally twice the cost of regular green anti freeze. No you can not mix the two, they are totally different products.
Before removing and replacing the thermostat attempt purging the air out of the system. This can be done by parting the vehicle on an incline or jacking up the front. This positions the radiator fill higher then the thermostat housing. With the vehicle off, remove the radiator cap and top off the coolant.
What ever you do, do not run the vehicle with the rad.cap off. Some one could get seriously injured.
After topping off, you will notice bubbled in the filler neck. As the level slowly lowers, top off again. This may take several tries. Once no more bubbles are present, Place your left palm over the filler neck, sealing the radiator. With your right hand squeeze the upper hose and release, do this a couple times before checking the fluid level. Add a splash more and continue. This may take a few times, before no more air bubbles are visible. Put on the cap and start the vehicle. Turn off all accessories including the heater and the fan. As the gage starts to increase temp. to over 1/4 turn on the heater, not defrost, and set the fan speed on low. This will open the heater control valve and allow coolant to flow through the heater core forcing out any air. At just over 1/2 the thermostat should open and the gage reading should drop slightly. Just under 3/4 the coolant fan should kick on and cycle, this will drop the gage reading down around 1/2. once the fan shuts off. Turn off the heater and the engine, lower the vehicle. You have purged the coolant system. Make sure to fill the overflow bottle to about 3/4. This will allow coolant to be drawn back into the radiator as the engine cools.
Hope this helps with diagnosing the problem. Christopher
Christopher
New member
That should have a 3.8L v6 and it is located below the throttle-body on the left/drivers side of the engine. Follow the upper radiator hose to it. It can be a pain to change.
What makes you think it's a thermostat problem? I wouldn't want to change it unless I was 100% sure that is what the problem is.
This engines upper intake plenum is prone to getting an internal crack in the composite plastic. When this happens coolant will get dumped into the intake. The amount depends on how badly it is cracked. This can be checked by removing the air inlet tube going to the TB. Open the throttle plate and with a flashlight inspect the inside of the plenum. It there is any coolant leakage it will be visible about 2 inches in from where the TB mounts to the plastic plenum. This part costs about 150 bucks and takes about 6 hours to replace.
An air pocket in the coolant system can also cause a thermostat not to open. This is because the thermostat has to be submerged in fluid to operate properly. It will not sense air temperature.
Your vehicle requires Dex-cool anti freeze that is generally twice the cost of regular green anti freeze. No you can not mix the two, they are totally different products.
Before removing and replacing the thermostat attempt purging the air out of the system. This can be done by parting the vehicle on an incline or jacking up the front. This positions the radiator fill higher then the thermostat housing. With the vehicle off, remove the radiator cap and top off the coolant.
What ever you do, do not run the vehicle with the rad.cap off. Some one could get seriously injured.
After topping off, you will notice bubbled in the filler neck. As the level slowly lowers, top off again. This may take several tries. Once no more bubbles are present, Place your left palm over the filler neck, sealing the radiator. With your right hand squeeze the upper hose and release, do this a couple times before checking the fluid level. Add a splash more and continue. This may take a few times, before no more air bubbles are visible. Put on the cap and start the vehicle. Turn off all accessories including the heater and the fan. As the gage starts to increase temp. to over 1/4 turn on the heater, not defrost, and set the fan speed on low. This will open the heater control valve and allow coolant to flow through the heater core forcing out any air. At just over 1/2 the thermostat should open and the gage reading should drop slightly. Just under 3/4 the coolant fan should kick on and cycle, this will drop the gage reading down around 1/2. once the fan shuts off. Turn off the heater and the engine, lower the vehicle. You have purged the coolant system. Make sure to fill the overflow bottle to about 3/4. This will allow coolant to be drawn back into the radiator as the engine cools.
Hope this helps with diagnosing the problem. Christopher
What makes you think it's a thermostat problem? I wouldn't want to change it unless I was 100% sure that is what the problem is.
This engines upper intake plenum is prone to getting an internal crack in the composite plastic. When this happens coolant will get dumped into the intake. The amount depends on how badly it is cracked. This can be checked by removing the air inlet tube going to the TB. Open the throttle plate and with a flashlight inspect the inside of the plenum. It there is any coolant leakage it will be visible about 2 inches in from where the TB mounts to the plastic plenum. This part costs about 150 bucks and takes about 6 hours to replace.
An air pocket in the coolant system can also cause a thermostat not to open. This is because the thermostat has to be submerged in fluid to operate properly. It will not sense air temperature.
Your vehicle requires Dex-cool anti freeze that is generally twice the cost of regular green anti freeze. No you can not mix the two, they are totally different products.
Before removing and replacing the thermostat attempt purging the air out of the system. This can be done by parting the vehicle on an incline or jacking up the front. This positions the radiator fill higher then the thermostat housing. With the vehicle off, remove the radiator cap and top off the coolant.
What ever you do, do not run the vehicle with the rad.cap off. Some one could get seriously injured.
After topping off, you will notice bubbled in the filler neck. As the level slowly lowers, top off again. This may take several tries. Once no more bubbles are present, Place your left palm over the filler neck, sealing the radiator. With your right hand squeeze the upper hose and release, do this a couple times before checking the fluid level. Add a splash more and continue. This may take a few times, before no more air bubbles are visible. Put on the cap and start the vehicle. Turn off all accessories including the heater and the fan. As the gage starts to increase temp. to over 1/4 turn on the heater, not defrost, and set the fan speed on low. This will open the heater control valve and allow coolant to flow through the heater core forcing out any air. At just over 1/2 the thermostat should open and the gage reading should drop slightly. Just under 3/4 the coolant fan should kick on and cycle, this will drop the gage reading down around 1/2. once the fan shuts off. Turn off the heater and the engine, lower the vehicle. You have purged the coolant system. Make sure to fill the overflow bottle to about 3/4. This will allow coolant to be drawn back into the radiator as the engine cools.
Hope this helps with diagnosing the problem. Christopher