99 venture overheating - help please

My wife called and told me she had no heat and the van was overheating. I'm thinking it was the thermostat so I bought one on the way home.

When I got home I found no (or very little) coolant in the radiator. I went ahead and replaced the thermostat since I don't think it ever has been replaced. After I topped off the fluid I still wasn't getting any heat and I found a bunch of air in the lines so I bled the air out for about 30 minutes and kept topping off the fluid. All looked good so I shut her down for the night. Today my wife called again and said it was overheating again but she was getting heat out of the vents.

What's going on now? I checked the coolant again and it only needed about a 1/2 quart to top it off.

Please help!
MARK

Probably the intake gasket or head gasket as became the huge problem with my '97. Make sure none of the coolant hoses are leaking though first. Definitely don't drive it and get it to a reputable shop who has done this stuff before and can check for hydrocarbons in the coolant, etc. Did the t-stat replacement first as you did and voila, still overheated as yours did. I replaced the intake, head gasket, machined the heads and did the radiator as well. Should have done the water pump as well since it leaked a few months later given the stress from the repeated overheating I went through. Water pump s/b replaced as well because it may start to leak now given the stress/pressure from the overheating. Do your t-stat again as I was told at the same time as well since it may have been compromised from the overheating. Plus, they will have all that stuff off anyway. Get rid of the Dex-Cool as well and replace with the green stuff it doesn't gel up like the orange does when there is air in the system and in case you don't change it every 15-20k miles. Go green. Be seen in green. Keep us posted as to what the root cause was and what you had to replace so we can all learn.

I had the intake gasket replaced 3 years ago. That's when I switched to green and have been green since. There's no leaks anywhere. If it was the head gasket, wouldn't I see some signs? Wouldn't it run rough?

You know that the mating surfaces where the intake fails seems to be badly designed per everything that I have read. It could be that again if you did use the Felpro gasket set, or there is a leak-through somewhere that needs to be found. Head gasket leaks supposedly appear as rough running engine, whitish watery exhaust smoke particularly at cold start. Its a definite pro job to detect, but still do not or limit driving. My intake leak after driving it too long also contributed to it needing the head gasket to fail as well. Sorry I cannot help more.

Well, I found out today that our van:

Has low compression in cylinder #2 (105 psi)
Has a misfire between plug #1 & #4
Needs new fuel injectors
Needs a new radiator cap
And needs the whole coolant system flushed

The tech told me it's not worth putting the money in to it and suggested an engine replacement. So should I replace, rebuild or get rid of it (my wife really wants to keep it)?

New radiator cap is $15, flush is $80-100 maybe, why does it need new injectors, can't they just be cleaned with a few tankfulls of gas and cleaner ($8-10 /can of injector cleaner). Low compression and misfiring probably related to either intake or head gaskets or others leaking coolant into the cylinders. Any wet plugs? I would try another mechanic/repair shop and determine where your leak is coming from, before making the decision. I had my intake and head gasket replaced, heads machined, new radiator and t-stat put in, including switching to green coolant all for $1365 here in San Diego. Stay away from the dealer repairing it given the cost. I would repair it if you can for under $2500-$3000. Any others want to comment?

I wonder if I should take my chances with a junkyard engine. I don't know if the plugs were wet. I'll ask when I pick it up. I've asked some locals if they would like to help me work on this since I don't have a garage to work out of. No answers yet.

First I would find out from someone else the causes of the low compression, etc in your own engine and get an estimate on doing that before any other engine replacement. You do not know how the other engine was taken care of, etc, unless it is a rebuilt.

Just had mine redone. Same problem, overheating , no heat. Dealer wanted 4600.00 for new engine. Small engine shop charges 1600.00 for new head and intake gaskets, new injectors, machining head, T-stat, water pump. running good for 3 weeks now

I just brought it home from the dealership. The temp light came on just as I got home (about 7 miles drive). I went out and put my hand on the radiator and it was cold. So was the bypass hose that goes across the front of the motor. The upper rad hose was hot and hard as a rock and the lower hose was warm, not hot. Do yo uthink maybe I have a plugged radiator or could a bad cap do that?

I am having the same problem, the engine was leaking coolant into the oil because of the manifold gasket. Had the engine cleaned and had the gaskets replaced as well as the water pump, and the thermostat. I took it out driving last night and am still having the same problem. The gage will go all the way in the red with no heat blowing from the vents but it seemed that when I hit a bump the heater will kick on and the temperature drop immediately. I parked it and checked and still have coolant in the resoviour. Any ideas?

Hate to write this but all symptoms (borell and sharkmonkey) point to head gasket failure. With exhaust invading the cooling system, pump cannot circulate water hence radiator is cold as well as heater. There are endless number of threads describing expenses in radiator, water pump, thermostats.....all ending with what one does not want to contemplate.. 3.1 and 3.4 are plagued with this problem...almost not a question of IF but rather WHEN....
I suggest you fill the radiator then run the engine without radiator cap: with what you describe, you should see exhaust bubbles pop from the liquid in radiator opening. Yes at beginning some of the voids will throw trapped air and exhaus but as you add liquid to make up, you will be left with stray exhaust at the end.
With one cylinder already identified as culprit as you describe (low compression) , I use to remove spark plug and force compressed air...that eventually pbubbles out at radiator cap..easy with a 4-cyl...but access here is not too good....

Yes, mine was definitely the head gasket. I had already invested about $2000 in repairs in the four years I owned the van. I wasn't about to sink another $4200 in it. I tried to get rid of it when the intake gasket blew the first time. I traded for a 2003 Town and Country and that was that. I'll probably never own anything Chevy again.

Reading all this scares me! Just bought a 2000 Venture, only owned it for 2 months and have had to sink $1500 in repairs and I have a feeling the lower intake is leaking (oil spots on the driveway)........Regret buying this car every day. Will NEVER buy another Chevy! I wonder every time I get in if it will start.......