Venture Cooling System

[dward110]

I have a 2001 Venture. The temp gauge usually registers at the very bottom of the guage as if the van has just been started. This has apparently caused the check engine light to come on. I've replace the temperature sensor and bled the air out of the coolant with the two brass bleed screws. Sometimes the guage registers the van as being warm but most of the time it shows the engine to be cold no matter what the temperature is. The heater doesn't appear to work very well either.

Thanks.

[clee425]

Start the engine, turn the AC switch off. See if both fans come on full. I just had the same problem. Found out that when i changed the sensor that the code had to be cleared out of the computer. Went to autozone and had the code cleared and the fans went off and gauge started working..

Donnie Lee

[GregA]

Originally Posted by dward110

The temp gauge usually registers at the very bottom of the gauge as if the van has just been started. ... The heater doesn't appear to work very well either.

It sounds to me like the thermostat is stuck OPEN.

Check the fans like clee425 mentioned. If the fans are OFF, I would start the van and let it run for 5-10 minutes and check the top radiator hose. If it is only getting warm (not HOT), I would suspect a stuck thermostat even more.

And yes, this can make the Check Engine light come on (if it does not get to "proper operating temperature" within a certain time). This would also keep the system cold enough to keep your heater from working well.

Take Care,

[dward110]

I'll go to autozone and have it cleared and see if the gauge works. The guage is intermittent so I don't know it'll fix it but I'll try it. The thermostat may be stuck open but I would still think the gauge would register something even if the thermostat is stuck open. One thing is, the gauge shows to be all of the way down when it's not working even if the engine is hot then I'll be driving and notice that the qauge is working again.

Thanks for the replies.

[RahX]

if a thermostat is stuck open the temp will never come up on an otherwise properly operating cooling system.

[Huney1]

"I've replace the temperature sensor and bled the air out of the coolant with the two brass bleed screws." Please tell me where they are located. Thanks. Easy way to see if the thermostat is working. Start the engine and have someone in the car slightly racing the engine, open the hood and hold onto the top radiator hose and it will gradually warm up then suddenly get very hot when the t'stat opens. Depending on how cold the ambient temp is you may have to hold on to it five or ten minutes.

Another trick. If it is stuck open, when it's cold take bottom of a coke bottle and tap the t'stat housing repeatedly with a firm tap and it might dislodge it and go in the closed position. You can use a hammer but be careful not to tap to hard. Another way, after driving for half an hour open the hood and feel the top radiator hose and it should be around 200F degrees to hot to hold onto. If it's hot and the heater not working good then the heater core is plugged with goo. (Dex cool strikes again.) You can blow it out with a garden hose but don't use a lot of pressure or you can burst the core.

I just read another thread where they said the heater dcore is high so you have to bleed the heater core to. Doesn't quite make sense to me because if you put the "in" hose on the bottom core inlet then it should force the air out the top as it fills the core from the bottom. DUH?

[dward110]

What I'm saying is that the gauge is at the very bottom even when the ambient temp is 80degrees and the van has been driven. The gauge doesn't register any temperature at all.

Thanks for the reply

[dward110]

Originally Posted by Huney1

"I've replace the temperature sensor and bled the air out of the coolant with the two brass bleed screws." Please tell me where they are located. Thanks. Easy way to see if the thermostat is working. Start the engine and have someone in the car slightly racing the engine, open the hood and hold onto the top radiator hose and it will gradually warm up then suddenly get very hot when the t'stat opens. Depending on how cold the ambient temp is you may have to hold on to it five or ten minutes.

Another trick. If it is stuck open, when it's cold take bottom of a coke bottle and tap the t'stat housing repeatedly with a firm tap and it might dislodge it and go in the closed position. You can use a hammer but be careful not to tap to hard. Another way, after driving for half an hour open the hood and feel the top radiator hose and it should be around 200F degrees to hot to hold onto. If it's hot and the heater not working good then the heater core is plugged with goo. (Dex cool strikes again.) You can blow it out with a garden hose but don't use a lot of pressure or you can burst the core.

I just read another thread where they said the heater dcore is high so you have to bleed the heater core to. Doesn't quite make sense to me because if you put the "in" hose on the bottom core inlet then it should force the air out the top as it fills the core from the bottom. DUH?

The screws are on the front left just over what is probably the water pump and on the right front where the water hose connects to the engine. The temperature sensor is close to it.

[dward110]

Originally Posted by Huney1

"I've replace the temperature sensor and bled the air out of the coolant with the two brass bleed screws." Please tell me where they are located. Thanks. Easy way to see if the thermostat is working. Start the engine and have someone in the car slightly racing the engine, open the hood and hold onto the top radiator hose and it will gradually warm up then suddenly get very hot when the t'stat opens. Depending on how cold the ambient temp is you may have to hold on to it five or ten minutes.

Another trick. If it is stuck open, when it's cold take bottom of a coke bottle and tap the t'stat housing repeatedly with a firm tap and it might dislodge it and go in the closed position. You can use a hammer but be careful not to tap to hard. Another way, after driving for half an hour open the hood and feel the top radiator hose and it should be around 200F degrees to hot to hold onto. If it's hot and the heater not working good then the heater core is plugged with goo. (Dex cool strikes again.) You can blow it out with a garden hose but don't use a lot of pressure or you can burst the core.

I just read another thread where they said the heater dcore is high so you have to bleed the heater core to. Doesn't quite make sense to me because if you put the "in" hose on the bottom core inlet then it should force the air out the top as it fills the core from the bottom. DUH?

By the way, isn't the thermostat at the back of the engine and too hard to get to to be able to "tap" it with a coke bottle?

[Huney1]

"By the way, isn't the thermostat at the back of the engine and too hard to get to to be able to "tap" it with a coke bottle?"

Hmmm . .. . Haven't really looked, BUT, 99% of engines have the t'stat in the front so it is easy to get to and work on, but being as how this engine is another GM work of art, it wouldn't suprise me if it is in the back and they made it as difficult as humanly possible to get to. Well, maybe you can take a Creepy and crawl under and take a flashlight and find it and whack it with a hammer and dislodge the stuck t'stat. JJEESSHH! The more I find out about this foul Venture beast the more I dislike it.

Anyway, thanks for the info about the bleed screws I'll cut it's throat and hope it bleeds to death.

[Shoes1980]

I have a 01 with the same problem. Gauge doesn't move off c and the electric fan on the radiator runs all the time!!!! HELP!

[clee425]

I had the same problem. The Temp Sensor that is by the thermostat housing was bad. Replaced it and then had the codes reset. Went to auto zone and they reset the codes and the temp gauge went back to normal and fans shut off.
Just purchased a code reader off ebay to check and reset the code myself.

Thanks,
Donnie Lee

[GregA]

Originally Posted by Shoes1980

I have a 01 with the same problem. Gauge doesn't move off c and the electric fan on the radiator runs all the time!!!! HELP!

If the gauge is stuck on "C" and the fans are on, there is most likely a code (DTC) set in the computer (see link below - fans on HIGH).

I would have the codes checked (see Donnie's comment above) to help identify the broken part and then replace it.

Venture Engine Cooling System

Take Care,

[cdru]

Originally Posted by Huney1

Hmmm . .. . Haven't really looked, BUT, 99% of engines have the t'stat in the front so it is easy to get to and work on, but being as how this engine is another GM work of art, it wouldn't suprise me if it is in the back and they made it as difficult as humanly possible to get to. Well, maybe you can take a Creepy and crawl under and take a flashlight and find it and whack it with a hammer and dislodge the stuck t'stat. JJEESSHH! The more I find out about this foul Venture beast the more I dislike it.

The thermostat is located under the throttle body. Follow the upper radiator hose towards the engine. Where the hose attaches to the metal elbow, that is the housign cover.

It's a PITA to replace thanks to the brilliant GM engineering. The easiest way to replace it is to replace it when doing a intake gasket. Well, that's not the easiest way but it's the most convienent then. The Haynes manual way of replacing it is to remove the cross over pipe which requires significant amount of work as well. Several people have said you can remove it, albeit with difficulty, without having to remove anything but the TB, but I've never done it that way.

[dward110]

I took the Venture to AutoZone and they read the code as the coolant temperature being too low. They say they aren't allowed to reset the computer any more so the check engine light is still on. The guy said to disconnect the battery to reset the code. I tried it and it didn't work.