1999 Head Gasket

[joeshannallie]

Just need a little advice on a few problems. 1999 Venture and the Heat Gauge will go all the way to the red before it seems like maybe the thermostat opens and it starts going back down. It is a brand new Thermostat. There is also a occasional coolant leak from the front of the engine. Not all the time just ever now and then. I first thought it may be a intake leak but when I replaced the Thermostat it looks like it is seeping from the corner of the front head gasket. Would this cause the heat gauge to be so erratic. I just got the van about 2 weeks ago. There is no signs of coolant in the oil or anything. If anyone has any advice please reply soon.
Also the heat at times in the van is cool as it sits and warms up. Takes forever at times for it to actually be hot out of the vents.

[Tech II]

Bought from a dealer or private party?

Why not return the vehicle with hidden problems? Certain states have laws for this....

Whenever you have a coolant leak, you create an air pocket, this air pocket, can block or partially block coolant from going through the heater core....that is why when the gage reads warm, you get no heat from the heater core(the heater core acts as the bypass, until the thermostat opens)......

From experience, when head gaskets go on this engine, it is usually the rear gasket, on the passenger side.....

You are seeing it on the front....it could be trickling down from the lower intake gasket......

In either case, the leak has to be fixed, and it will be expensive.....so is returning the vehicle an option, or was this an "as is" situation? In some states, cars are sold this way, but it's illegal....check with your local Registry....

If you are stuck with the car, you must determine if it's a head gasket or lower intake or Both......if misdiagnosed as just a lower intake job, you will be doing the job twice, so get the proper diagnosis......

[joeshannallie]

Thanks Tech for your reply. It was a private buy so returning is not a option. So the best solution is to pull the heads and take them to the shop and have them checked, Right? And then just do new gaskets? It does not seem like it will be a hard job. Just time consuming. Just one of them that you have to make yourself do.

[joeshannallie]

Tech do you know of a sure way to test the fans to make sure there is not a relay problem or anything. Both fans do come when you turn on the A/C. I also want to know why the heat gauge hand stays where it is when you turn the key off. When you restart the van later the hand goes back to where it is suppose to be and then starts going up. Gas hand does the same. I have replaced the fuel level sensor in the tank recently.

[LMP]

BOth fans ON with A/C: normal
Needles stay where they are: normal. they are electrically positionned..no spring return. when you turn the current off, they have no power to go elsewhere.
Erratic heat from the heater ..plus other symptoms you describe . are sign of blown head gasket...a common issue with this engine. Several just around me, tons on this and other GM forums with 3.1 and 3.4 engines. Exhaust invades the cooling system and no venting of purging will restore normal behaviour. In a normal engine, any residual "air pocket" is carried out to the top of the radiator with time...generally just a few operation cycles. WHen exhaust is pushed into the cooling system through a gasket leak there is no way to clear it because it is coming all the time the engine runs.
THe "heads" are probably OK..the head gaskets not.