Heater and temperature guage issue

[ahmed1979]

Hello everyone,

I bought a chevy venture 99 today. After about 5 mins of starting the car the temp. goes to the middle of the guage and then it drops close to 40. During that period the heater acts funny. When the temp is in the middle the heater blows warm air. When the temp drops down (fast) the heater blows cold air. This problem also occurs while I am driving the car. But after driving the car for another 5 mins the the needle in the guage stays close to the first dash at 1/4 and the heater works fine. Is this normal? The dealer where I bought from says that it might be a thermostat or a sensor. Could that be the problem? or is it the gasket going bad?

Thanks for the help.

[pencilor]

The same thing just started happening to our 2001 venture last night. If anyone has any suggestions I'd appreciate it. Our 2002 windstar is in the shop right now because the key wouldn't turn and I'm 8 mos pregnant and NEED a car!

Please respond if anyone knows what this is!

Thanks!!

[pencilor]

Okay, Hubby just got home from cutting firewood and I had him check the oil. Sure enough there is a mayo-like substance so it's our intake. We are going to attempt it ourselves with some friends and plan on changing the head gaskets at the same time. Good luck to you!

Edited to add: Thank you to everyone for their previous posts in the forum. You've helped us figure it out w/out paying a diagnostic fee. Now we just need to get the Haynes manual and parts and a whole lotta time!

[ahmed1979]

Yeah, you were right. It was the gasket. Thanks to God it was leaking outside the engine. I took it back to the dealer (none GM) here in Ottawa, Canada and he agreed to pay for half the cost. I got my 99 Venture last week for $4500 CND (132K Km or 82.5k Miles) The guy fixed the ABS which costed him $600CND and he go an estimate between $500-$600 CND and I will be paying half of that. I love the car so far and I pray that I will stay in love with it

[cdru]

In cold weather, the same mayo-like substance can form on the radiator cap just due to condensation within the oil. A hard drive will burn off any moisture in the oil. If it is an internal leak, the gunk normally will remain. If you get the engine up to operating tempature for about 10 minutes and check again and it's gone, it probably was just normal condensation and nothing to be concerned about.

[pencilor]

Crdu,

Would that cause the temperature and gauge issues? It was only about 10 degrees out here and we were at a friend's house so it was parked outside.

Edited to add:

Actually, the more I think about it, we are losing radiator fluid too so it has to be the intake. Thanks anyways!

[cdru]

The actual temp fluctuations almost sounds like a faulty thermostat, one that at some point opens quickly flooding the engine with cold coolant from the radiator which causes the drop. I recently battled a similar problem like yours after I replaced a thermostat in my Cavalier. It couldn't hold shut under engine pressure and would "leak" coolant past the thermostat. Highway speeds would cause the engine to run colder then normal.

The leak though should be investigated first though. If it is the intake, just replace the thermostat (with a quality one) when the intake gaskets are done.

[Shoes1980]

Any fix yet ? Mine is doing it too. Gauge at c and the electric fans running all the time!!!!

[ahmed1979]

Hello every,

The gasket has been fixed but the temp gauge is still fluctuating. Since I got the Venture with this problem, where should the needle be in the normal circumstances be?

I noticed that in our car if the transmission on park, the needle will stay on the middle of the gauge while if we are driving it drops to the second dash after 40 degrees and stays there. Would the next thing to replace be the thermostat?

Thanks