Engine Overheating?

2001 CHEVROLET VENTURE
80,000 MILES • 3.4L • 6 CYL • AUTOMATIC
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CKLOPP9
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HI..
I have a question concerning my 2001 Chevy Venture 3.4L. It is experiencning overheating problems , seems to be air in the cooling system. However everytime we go to start the van we need to let it heat up for about 20 minutes prior to driving it or it will overheat and sometimes it will overheat and all of a sudden drop to normal temperature. We have bled the air out and then it works fine for a few days and then starts to overheat again...could there still be air in the system?? Another problem it is having is that we were driving on the highway a little over a half tank of gas and all of a sudden the engine starting like puling when pushing the gas down and then we slowed down to stop and the engine turned off. When we went to try to turn it on it wouldnt turn on right away but after waiting for a few minutes it started. We ran a few feet and it started doin the same thing again. We were able to make it to our house by hardly pushing the gas down because everytime we pushed the gas it started the pulling again . COuld this be either the camshaft or crankshaft sensor??? Please help.
May 5, 2015 at 4:42 PM
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JDL
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As far as air in the cooling system, have you had any repairs done on the cooling system, recently? Are you losing coolant? Do you have to keep adding coolant?

How hot does it get in degrees F? Your radiator fan work ok? Other than the temp gage any signs of overheating? Is the engine smoking? Does the coolant boil over, anything like that? Have you ever replaced the thermostat? Where applicable, you could remove radiator cap, cool engine, start the engine, watch the coolant level, if it starts rising really fast, have to check for head gasket issue. Could be other issues, water pump, radiator, something like that.

This guide can help us

https://www.2carpros.com/articles/engine-overheating-or-running-hot


With engine running issue, are you saying it bogs down when you step on the gas? If so, the basics say to check for blockage of some kind, fuel--air--exhaust. How long since a tune-up?

Can you check for applicable trouble codes? Some of the national brand auto stores will check codes for free, if there are any.
May 6, 2015 at 11:02 AM
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VANN383
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My van keeps overheating. I have replaced thremostat, water pump, and have flushed it twice, bled air from system. It still overheats i am not loosing antifreeze at all. has me stumped!!!
Aug 21, 2020 at 11:49 AM (Merged)
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MERLIN2021
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Have you check for cooling fan operation? Operation of the ECT? that's the temp sensor...if it doesnt tell the PCM it's hot, the fan wont come on.
Aug 21, 2020 at 11:49 AM (Merged)
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VANN383
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when its overheating didn't see fans come on. I did turn on the defrost cause i knew it would make the fans run and they did. how would i test temp sensor? Is it the same sensor as the gauge because gauge and warning light come on?
Aug 21, 2020 at 11:49 AM (Merged)
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MERLIN2021
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Turn on the a/c and see if the compressor runs, if it does check fans 1, 2, 3 relays in the underhood junction block. If the compressor does't run check that relay in the same block The ECT is on the front oe the engine, I think it serves both purposes. test it with an ohm meter as the engine warms the readings should change. I will email the tests to you...
Aug 21, 2020 at 11:49 AM (Merged)
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SYMIJECO
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My 2001 Chevrolet venture van has is still overheating, even after I have changed the head gaskets, water pump, thermostat, and bled the system 4 times. the van starts up and runs fine, seems to be running at the right temp, and then starts to overheat, and pegs the gauge.
Aug 21, 2020 at 11:49 AM (Merged)
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CJ MEDEVAC
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Is the cooling fan operating?

Operating during the time of overheat?

Is it possible that the radiator has minerals and deposits stuck inside its vanes, degrading it's ability to work correctly?....Our water does that around here, a professional tear-down and cleaning/ rodding is the best thing, next to replacement.

Maybe it's something as simple as a radiator hose, old and squishy, being s.ucked flat due to water pump action?

The Medic
Aug 21, 2020 at 11:49 AM (Merged)
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SYMIJECO
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I have had the radiator flushed and check, insuring that the flow through it is unrestricted. The hoses are new. You can drive the down the road, no overtemp, the minute you sit for just a few minutes, the temp gauge starts pegging. the fans appear to be kicking on.
Aug 21, 2020 at 11:49 AM (Merged)
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CJ MEDEVAC
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How was the radiator flushed? Professionally or a Auto Store Pour in flush?

Sorta when does it kick in, according to the temp gauge?

The Medic
Aug 21, 2020 at 11:49 AM (Merged)
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CSVIAL
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I have a 2001 Chevy Venture MiniVan that started overheating suddenly. I replaced the thermostat, and now the coolant temp. sensor/sender. The fans do kick on but it seems later than it should. Still overheating and out of ideas, please help!! Thanks
Aug 21, 2020 at 11:49 AM (Merged)
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SATURNTECH9
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Hello,

These cars had problem with the head gasket which makes them overheat. To confirm the issue please run this test

https://www.2carpros.com/articles/head-gasket-blown-test

and

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please run down these guides and report back

Cheers
Aug 21, 2020 at 11:49 AM (Merged)
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CSVIAL
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Fans kick on at about 160°
Aug 21, 2020 at 11:49 AM (Merged)
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SATURNTECH9
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Thats too cold did you use a temp to get this temp?They usually come on at 222-226 degrees.
Aug 21, 2020 at 11:49 AM (Merged)
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CSVIAL
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Yes, took the temp on the cap, not sure why it is so much cooler, the temp on the line is 230,this time when it kicked in. It's got me confused the outlet at the thermostat is 230 but the inlet to the pump is only 200, yet the gauge still keeps climbing.
Aug 21, 2020 at 11:49 AM (Merged)
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SATURNTECH9
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When it gets that hot measure the temp of the upper and lower radiator hoses.Sounds like your thermostat might not be working correctly.
Aug 21, 2020 at 11:49 AM (Merged)
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KELLYECKBLAD
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I have put on a new waterpump.And put on new hoses and bought a new thermostat and then decided to take it out.but do I need a thermostat in my van to keep it from running hot?
Aug 21, 2020 at 11:49 AM (Merged)
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CSVIAL
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K, this time was 270 on the upper and 230 on the lower. The thermostat is about 1 day old, and was the worst to replace I have ever seen I hope that it's not bad already.
Aug 21, 2020 at 11:49 AM (Merged)
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WRENCHTECH
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I'm not sure exactly what you are asking but yes, you must have a working thermostat at all times. Never remove it thinking it will help an overheating problem.

That engine is also very difficult to get all the air bled out of the system. We use a vacuum tool to draw the air out.
Aug 21, 2020 at 11:49 AM (Merged)
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SATURNTECH9
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Sounds like the thermostat is working are both fans running on high when its that temp?Also have you made sure the cooling fins of the radiator arent clogged with sand fur debris etc causing not enough air to be pulled thru the radiator?
Aug 21, 2020 at 11:49 AM (Merged)
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CSVIAL
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Fins are clear, fans are on high. Have re-bled about 5 times, have now resorted to just draining the whole system and flushing to make sure there are no clogs. I've never had such a headache from a cooling system before so I finally did what you suggested and tested the head gaskets, they are blown :( going to cost me $1300.00 but at least I found the problem. Thanks for hanging in there with me.
Aug 21, 2020 at 11:49 AM (Merged)
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SATURNTECH9
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Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers
Aug 21, 2020 at 11:49 AM (Merged)
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VICKIE HAMPTON
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I have replaced the thermostat and also the radiator and the return where it goes into the overflow. it would not return to the radiator. I have to keep bleeding it in order to get heat and I have to drive at slow speeds in order for it not to overheat. I replaced the water pump last year. I do not know what is going on and why it will not do the return from the overflow bottle. do you have any suggestions as to what could possibly be wrong?
Aug 21, 2020 at 11:49 AM (Merged)
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HMAC300
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when the car is cold it goes from the overflow bottle to radiator. fill cooling system up and have it pressure checked you may havea bad intake or head gasket causing the overheat.
Aug 21, 2020 at 11:49 AM (Merged)
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WALKERGETX
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This is my late father’s van that he kept garaged and maintained meticulously. I let a friend borrow it for two weeks in January in CT. He doesn’t have a garage. After about a week and 500 miles, the temperature gauge started shooting up within a couple minutes after startup. Took it to a mechanic who changed the thermostat, then the sensor, then looked at the water pump. All fine. Said he did a cylinder head check but it came out fine. Now says it has to be a cracked or warped head.

No coolant in the oil, no blue smoke out the tailpipe. Could exhaust be leaking into the coolant, creating an air pocket? Replacing the head is more than the vehicle is worth. Thoughts?
Aug 21, 2020 at 11:50 AM (Merged)
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KASEKENNY
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I am confused on how he checked the head and now he says it has to be cracked or warped.

I don't doubt that could be the issue but if he tested it then that shouldn't be the case.

There are a couple ways to test for this and I attached some guides here.

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/head-gasket-blown-test

However, we need to find out if the cooling fans are coming on or if there are another cause of this overheating.

https://www.2carpros.com/articles/engine-overheating-or-running-hot
Aug 21, 2020 at 11:50 AM (Merged)
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MINDYPK8
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I have a 2000 chevy venture and it keeps over heating, when the light comes on, i pull over and turn it off, wait 20 mins and its cool enough for me to open the cap, when i do the water starts flowing from the over fill into the radiator, and this happens?

It doesn't make sense for the car to be over heating and for it only to take 20 minutes for it to cool down, and it worked perfectly fine all summer running the air conditioner so any help is really appreciated

Love the site :-)
Aug 21, 2020 at 11:50 AM (Merged)
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FIXITMR
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smell any antifreeze under hood when hot? are you losing any antifreeze? is cooling fan coming on?
Aug 21, 2020 at 11:50 AM (Merged)
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MINDYPK8
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yes I smell the anti freeze, and the person i bought the car from almost a year ago took it to mechanics all the time and they unhooked the fan, they bipassed it somehow, but it ran perfect for months and months like that
Aug 21, 2020 at 11:50 AM (Merged)
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FIXITMR
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these are known for failed intake gaskets which cause overheat and loss of coolant. can you check if they have been replaced already?
Aug 21, 2020 at 11:50 AM (Merged)
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FIXITMR
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also thermostat may be sticking shut?
Aug 21, 2020 at 11:50 AM (Merged)
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MAKDG7
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I had changed the antifreeze , radiator cap, and thermostat. The van has rear heat, I keep bleeding the air out of the system and i'm getting nowhere fast, i've noticed that there is a motor type thing or a pump to the left side of the overflow tank, I can only get it to run if I run jumper wires to it. Is this thing causing any of my problems?
Aug 21, 2020 at 11:50 AM (Merged)
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SERVICE WRITER
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Fair chance of a leaking intake manifold gasket. Seen many of these on this truck. Are continuing to have to add coolant or is it staying full?

Post a pic of what your hot wiring.

Are the cooling fans operating when the engine reachs 220-230?
Aug 21, 2020 at 11:50 AM (Merged)
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DENNYP
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I agree with possible intake gaskets leaking. The motor you are talking about is for the seconday air injection system.
Aug 21, 2020 at 11:50 AM (Merged)
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MAKDG7
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Well do you know if that pump is suppose to run all the time then? Because I have noticed that there is no power to the plug on it, I tested it with a test light. Also does it run off of a relay or fuse if so where is it?
Aug 21, 2020 at 11:50 AM (Merged)
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JAMES36
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why does the antifreeze bubble like its overheating in just the overflow container but the rest of the system is perfectly fine?
Aug 21, 2020 at 11:50 AM (Merged)
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SGMWHITE
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2000 Chevy venture van 3.4l still over heating, after replacing thermostat, radiator cap, fans work properly. checked relays and all seem to work properly. van Idles fine, then will get to normaol temp. and all coolant will go into overflow tank. using temp gun on thermostat housing, block, water pump all temperatures seem normal (ie thermostat 180-220, water pump 150-160) not sure what to check next.
Aug 21, 2020 at 11:50 AM (Merged)
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RASMATAZ
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Check the radiator if its clogged and also try bleeding the system could be airlock-if okay have it block and pressure tested to find out more what's going on.
Aug 21, 2020 at 11:50 AM (Merged)
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PROTECH1980
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Hey Raz, sounds like he is pumping combustion gases into the cooling system from a cracked aluminum cylinder head or bad head gasket, most likely cracked head, call around and find a shop that does chemical head gasket tests, simple test to tell if there are combustion gases in coolant, it will save alot of time and money(unecesary parts) trying to figure it out.
Aug 21, 2020 at 11:50 AM (Merged)
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EARL.OWENS
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I was driving and my serpentine belt just came off, it didnt brake or nothing it just came off. The pulleys are no longer turning and the van over heats now if I drive it. Can you tell me what cause this and how I would be able to fix it and will it cost a lot to get it fix? thanks
Aug 21, 2020 at 11:51 AM (Merged)
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SATURNTECH9
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Have you checked the belt tensor yet?
Aug 21, 2020 at 11:51 AM (Merged)