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Heat without a thermostat, no heat with one and car overheats


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jlwinfield
New User

Feb 18, 2013, 4:44 PM

Post #1 of 10 (1713 views)
Heat without a thermostat, no heat with one and car overheats Sign In

I purchased a 2004 Chevy Impala, 3.4L engine about 140k miles less than a year ago. About a month ago I blew a hose to my radiator and noticed it seemed to be clogged with gunk. (apparently someone put some stop leak in the radiator) Anyhow, I had the radiator replaced and a coolant flush done (which seemed to be ok techs never said anything) well in order to get the car to get flushed I had to remove the thermostat to drive it. We had heat after the flush still without the thermostat. When I got home we put in a new thermostat and the car began to overheat and we had no heat. Assuming it was a faulty thermostat I went back and replaced it again still same problem. Can it be my heater core?????


Tom Greenleaf
Ultimate Carjunky / Moderator
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Feb 18, 2013, 5:07 PM

Post #2 of 10 (1694 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

If stop leak was used there no doubt was a leak or a feeble attempt to cover up a bad head gasket. The professional flush should have included the heater core and any problems flushing it noted if it didn't flow.

Who is messing with the thermostat now - you? For the moment it seems like there's air in the system from improper refill and without a thermostat it probably can blow enough even if just warm coolant thru heater and with one not enough passes thru a thermostat to make it. Overheating to boiling inside will not throw heat much or at all - it takes liquid coolant in the core to transfer heat.

Gotta know it's properly filled with coolant first. Put thermostat back in as you are wrecking things running without one. Hope it can end there and the leak was the radiator which is now new but might not be. Pressure test system now without stop leak junk in it and see if there's another leak AND do test for a bad head gasket!

It could be pushing combustion gasses into cooling system which will overheat, heater would quit not just the commonly thought of coolant in oil or steam out the tailpipe. Head gaskets can fail in several ways and this engine is known to be on the problem side as they go,

T



jlwinfield
New User

Feb 18, 2013, 5:18 PM

Post #3 of 10 (1679 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

I only ran the car for the flush without the thermostat. I have someone working on the car and he did put back in the thermostat. I will see if there are any leaks but its looking to be a head gasket problem :( thank you tho


Hammer Time
Ultimate Carjunky / Moderator
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Feb 18, 2013, 5:22 PM

Post #4 of 10 (1672 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

No, it's likely air pockets as Tom suggested.
That engine is very difficult to get all the air out. We use vacuum fill.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 18, 2013, 5:24 PM

Post #5 of 10 (1665 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

OK - thermostat out for flushing for that time is fine. Some people think you can run without one and you can't for too many reasons to list. Good luck. Hope it's not a head gasket issue but hang on for that news. -- T


jlwinfield
New User

Feb 18, 2013, 5:31 PM

Post #6 of 10 (1656 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

ok stupid question....Vacuum fill....sorry im a girl lol and husband is at work....just fed up with this car, how would i go about that?


jlwinfield
New User

Feb 18, 2013, 5:32 PM

Post #7 of 10 (1651 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

again thank you for the advice i really appreciate it and will post more as I know...:)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 18, 2013, 5:36 PM

Post #8 of 10 (1644 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

You would need one of these






http://www.tooltopia.com/uview-550500int.aspx




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 18, 2013, 5:40 PM

Post #9 of 10 (1635 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

Vacuum filling is done with a machine that puts cooling system under a vacuum and fills it completely the first time vs the age old (still works on some run a car, wait for thermostat to open, fill till it wont take more as it self purges out air. Many more vehicles just don't cooperate to get all the air out by themselves. Increasingly shops just don't have time to play games to fill a system either. Even the regular way takes time and some know how,

T



nickwarner
Veteran / Moderator
nickwarner profile image

Feb 18, 2013, 10:39 PM

Post #10 of 10 (1607 views)
Re: Heat without a thermostat, no heat with one and car overheats Sign In

Sounds like an air pocket to me too. But a few things to bring to mind for you.

Never drive a computer controlled car without a thermostat. It keeps the temps low and thats a bad thing, because your computer dumps fuel at low engine temps. Drive around like that and your cat will fail. A $500+ fix depending on where you go.

Be careful who you let fool with your car. Just because someone knows where the hood latch is doesn't make him a mechanic and he can easily do thousands in damage and be liable for nothing. There is a reason we charge for what we do. We spend years learning the right way to do it and a small fortune in tools to do it with. If I could get back all I've spent on tools just since 04 I could buy a decked out Escalade in cash. All the rest of the mods here are in the same boat. Good work isn't cheap.

Vacuum filling has become the industry standard on GM especially because they get the worst air pockets and take the longest to get out.






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