Engine Overheating? Cooling fan starts working too late?

Engine Cooling problem
1999 Chevy Venture 6 cyl Front Wheel Drive Automatic

I bought this 1999 Chevy Venture when I was driving it would stay cold for a long time then heat up then drop down cold again and keep doing that I changed the thermostat and the waterpump is good
there is no head gasket problem and the fan seems to be working. What is my next step?Flushing my system?Or could it be a sensor?

Engine problem
1999 Chevy Venture 6 cyl Automatic 100509 miles

my engine is over heating in I have exhaust coming in from the vent if I turn on the heater or air. I do not have water in oil. I check to see if I crack head. Do you think my fan has gone out

Ok first I have a overheating problem well I did a couple things ive put it back together and now I believe I did not connect the vacuum lines correctly it shuts off right away

My 1998 chevy venture is overheating but not loosing coolant from radiator but u smell anti freeze resovoir fluid is orange

Then you have a leak. Either a hose or intake manifold gasket. Pay the 97 bucks to have Chevy diagnose it. It is WELL WORTH IT!

If you smell it inside the vehicle your heater core most likely has a leak, before taking it in another thing to check is the coolant level in the radiator, sometimes it the cap is bad, or the resevore tube isnt down far enough it won't drain into the radiator. This happened to my inlaws 98, they had no heat and just looked under the hood at the tank when we went to change the thermostat we discovered the radiator was half empty

Engine overheated. Had already replaced the radiator because of a leak. So next was the water pump and thermostat. That didn't fix the problem, so the manifold intake gaskets were replaced. It was OK for awhile, about 50 miles. The needle will flucuate rather wildly, going up when idling at a light, then back down while moving. The radiator overflow tank will be totally full. When the bleeder valve is opened a lot of air will escape. No coolant in the oil. Mechanic says it could be head gaslet, but could also be cracked block or head. He recommends putting in a different engine. Last time I drove it any distance, I stopped at about 80 miles because it was staying very hot, opened the bleeder valve, bleed out a lot of air. What can or should I do?

My mechanic said he hadn't done the dye check, but had checked carefully and couldn't find any evidence of any leeks. I have been driving it for a couple of weeks, I open the bleeder valve when I park(usually a lot of air). Before I head out I close the bleeder valve, and often add to the radiator. The overflow tank is totally full, but the radiator will accept a couple of quarts, added slowly so air can escape. No sign of antifreeze leeks, or white vapor at the tailpipe. Where is it going? It hasn't overheated, but the needle flucuates, from cold while moving, up to hot while idling and back down again when moving.

Had thermostat replaced two weeks ago. Have less than 300 miles since. Also the fluids were changed. My low on coolant light has been coming on every two weeks, since about 100,000 mi. So I add coolant mixture to overflow frequently. Have had overflow tank changed and waterpump and hoses. I live on ss so don't have maintenance money. Friends have been working on it.

Thank you for your quick reply. I'll talk to my mechanic, I guess that's why he looked for engine. He mentioned something called Blue(something)that is supposed to fill cracks, etc. Said he still had half a can(enough to do the job). He didn't like it and didn't want to use it. But my question; if the engine needs to be replaced anyway, what would it hurt to try. Do you know the stuff and what other problems it may cause?
The van looks good and runs good, otherwise.
Thanks, Alice

Thanks for the info. Doesn't sound good.

Engine Cooling problem
1998 Chevy Venture Automatic

For some time now my Venture has been kind of sputtering here and there, but we thought it was just the gas we put in it or something because it would seem to stop for a long time and then do it again for a bit. Last night the sputtering started again so I drove home. This morning during a short drive the temp skyrocketed. It seems like the radiator fan is cutting on and off. The fuse looks fine. When the fan comes on it cools down fast. The fluid was a bit low so I filled it up. I don't know much about cars, but was hoping to get some feedback as to what the problem might be.