Hanno Brand

Hello all, I've been reading a lot about the problems of overheating and off course my 1999 venture has it too. When i bought the car last summer it was standing still for a while but everything worked except the ac. I drove it some short distances with no problem. But after a while it overheated after a 25min drive and wouldn't cool down. Then i started looking... so here come a long story but i try to be as complete as i can... i flushed the radiator and old brown coolant came out, i also replaced the thermostat at that point. Filled it up and bleed it with the screws.. when i drove it then i saw the temperature going up and down the whole time and the heater took long to give some warmth it didnt do that before. I searched for what it could be and it all pointed to air in the system. So i tried to bleed it again and yes got some air out but not much. Then when i drove it the next time the temperature fluctuated still untill it overheated again after about 30 mins of driving. I used the bleeding screws again while engine was hot and a lot of air/steam came out. I waited a bit for it all to cool down and i noticed that the overflow tank released the coolant back to the radiator. So i drove futher and for an hour continuously driving it was good. Also the hearter worked perfect it was very warm on full heat. I parked at my destination and after 15mins or so i drove back and i gave it a little more gas not crazy full throttle just some more power and yes again i noticed the heater losing its heat and the temp raised up again till i had to stop again cause of overheating. But now when i bleed it still gives lots of air/steam only the coolant doesn't go back from the overflow tank to the radiator. Only when its cooled down completely its back in the radiator. So next thing i did was replace the cap for a new one and i saw on youtube an how to bleed the system for these cars by using a plastic bottle that you put on the bleeding hole above the waterpump. So i tried that and yes lots of air came out i let it idle and some times rev it a bit to purge out all the air for 40 mins or so. The temperature was very consistent and the heater worked good. So agin time for a drive with good hopes, but again even quicker now within 10 mins drive overheating. And again lots of air/steam coming out the bleed screws. In the mean time i read a lot about people having heating and air issues with these cars and that the waterpump might be having trouble getting it through the system with the auxiliary heating. So then i tought hmmm ok ill get a new waterpump and plug the lines to the heatercore in the back. So i placed a new pump and plugged the lines at the tee what was a pain to reach but the heater in the back is also ruled out now. And with good hopes filled and bleed with the bottle technique again. What takes realy long cause i just keep seeing air coming out. And again everything when the car is parked idling and reving a bit workes fine hear gives very warm air and the temperature is consistent. But even if i idle it for 30 mins the fans (they do work didnt mention it yet but they work) wont go on and the temperature wont go that high for them to go on. Now its probably because its not so warm outside just around 10°C (sorry from Europe dont know how much F it is ) but again time to drive feeling very hopeful again.. and all hope gone again after 10 mins of driving temperature goes up to red again and light comes on again too... so bleeding again with lots of air/steam.... i noticed now that when i drive i can control the temperature by driving below 60mph if i go closer or over 60mph it will overheat but if i stay on low speed i can manage it a little but still its goes hot but returns to go hot again. And when it goes down i feel hot air in the car and when it heats up the air in the car cools down... now what is the problem how does air keep getting into the system? I dont see it leak coolant i dont know if i have a leak intakemanifold gasket or head gasket. But shouldn't that also give other signs like weird smoke from the exhaust or bad idling cause that is just fine with the car it idles very smooth and no blue or white smoke only at start when its cold but just for a little. Who has some good ideas ? I know a pressure test will help but i dont have that and maybe its still that little overlooked thing... sorry for the long story but i try to have a complete story.

Irish_alley

not all head gasket leaks will suck coolant into the combustion chamber. my cummins would only overheat if it had the turbo hooked up. replaced the head gasket and no more issues. before i replaced it it would put coolant into the overflow and woudl fill the block will air. the only real way to see is have your coolant tested for exhaust gas contaminates.

Mike Waite

Omg you just described what I have happening as I write this. 2001 3.4L venture 110,000 odometer same thing I replaced thermostat then water pump it is getting ready for a head gasket job now I was looking online to find a local place to go

otheym

My 2004 venture is doing the same thing. After it warms up the temperature fluctuates up and down to the red zone and back. The heater does not work and the expansion tank fills up completely. The fans come on sometimes and sometimes not at all. I have had it towed to the shop twice and the mechanic has not been able to fix it. I think it may be a faulty gasket. The water pump and thermostat are OK according him. I am wondering now how much I could sell it for or if I give it to a charity how much I could deduct from my taxes. The van has given me grief since day one. I am tired of the problems it has and just want to get rid of it

ventureguy

If both fans don't work even with the ac on try hot wiring them. My 2003 Venture with 165,000 miles sometimes gets a little extra warm in stop and go traffic.
i have to turn on the ac then both fans are on. Also it might be the Temperature Sender / Sensor on the front top of the motor. if the fan motors are bad you
can buy just the motors themselves and also the Temperature Sender / Sensor at Rock Auto fairly cheap.

Photon440

I just did a head gasket replacement on my 2003 Montana (same van and engine as Venture) due to fluctuating temp gauge, heater not working, the usual problems. I also had coolant entering the oil so I was hoping it was just intake manifold gaskets. But I pulled the heads anyway, and one gasket was pretty bad, corroded through the fire ring right to a water port. It's been running as it should since the repair. I used a Felpro gasket set, it had better engineered gaskets than what the factory used. I put in new head bolts as well. Gaskets and bolts cost about $260 Canadian.