Overheating Engine?

Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
I would say that the heater core has failed, a cooling system pressure test will prove this one way or the other.

Mark (mhpautos)
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
KYNANB1
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  • 2 POSTS
Thanks Mark I kind of felt it was but wanted a reassured answer.
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
JMCJAMES
  • MEMBER
  • 1 POST
  • 1993 VOLKSWAGEN JETTA
  • 4 CYL
  • 2WD
  • MANUAL
  • 60,000 MILES
While driving I noticed the temperature gauge was reading very high, so I pulled over and coolant was coming out of the expansioin bottle. I removed the stat. And topped up with water. It continued to overheat.
When I got home, I ran it until it overheated and noticed that the cooling fan only kicked in as coolant started to come out of the expansion bottle. So I replaced the thermal switch. Drained and flushed the system - all appears clear. Refilled system - ran it two/three times heat up - cool down to get rid of air pockets. Took it on the road maybe 5/6 miles stopped and let it running, it was bubbling slightly not bad thought it might be air. Returned home and let it cool down. Topped up when cool - 2pts. Now runs fine maintains proper running temp while driving but once I stop the engine coolant starts coming out of the expansion bottle. I've disconnected the overflow piipe to the top of the expansion bottle and got someone to bring the engine up to 3000rpm and coolant squirts out. I was told that this wouldn't happen if my water pump wasn't working. Help! I'm at my wits end. The model is a VW Vento a variation of the Jetta that VW brought out over here in Europe. It's got a 1.4ltr engine.
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Have it checked for a blown head gasket.I have seen many vehicles that would be fine until they were driven then they would get hot and spit out coolant and even overheat if still driven. Especially if it is using coolant (low without spitting any out). Your local shop should be able to do a chemical test for you to see if there is any exhaust present in the cooling system for a reasonable price, the test isnt 100%, but it is real close
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
MCM.
  • MEMBER
  • 1 POST
  • 1991 VOLKSWAGEN JETTA
Heater problem
1991 Volkswagen Jetta 6 cyl All Wheel Drive Automatic unknow miles

My car has overheated a couple times and is at the point where it might overheat again. When I see the the thermostat go up I crank up the heat causing the thermostat to back to normal.

I don't know much about cars but I know the thermostat has been changed.

Any ideas on what's wrong?

Thanks
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
DR LOOT
  • MECHANIC
  • 2,311 POSTS
Because you have overheated the vehicle the thermostat is now no good, what I would do is have the thermostat removed and drive it and see if it continues to overheat, since you have to replace it anyway. You may have a bad water pump or plugged radiator, but to start our diagnosis, lets start by removing the thermostat and see if the problem continues.
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
SWITCHCRAFT
  • MEMBER
  • 5 POSTS
I am having the same problem it keeps overheating.

I have removed the thermostat and it still overheats

what do I check next?
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
DR LOOT
  • MECHANIC
  • 2,311 POSTS
The only thing I can think of now is you have a blown head gasket, remove your spark plugs and let me know if any of them are wet.
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
SWITCHCRAFT
  • MEMBER
  • 5 POSTS
Plugs are not wet, what do I check next?
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
DR LOOT
  • MECHANIC
  • 2,311 POSTS
OK, is the radiator fan coming on when it gets hot? If it is, you are going to have to go to your local parts store preferably Harbor freight, and purchase a infrared temperature gauge so you can check the temperature on the upper radiator hose and the lower radiator hose to make sure you are getting flow through the radiator, and let me know.
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Monday, July 27th, 2020 AT 4:34 PM (Merged)
Tiny
TREES
  • MEMBER
  • 14 POSTS
How is the coolant level?

Before you do anything invasive, such as paying for a head gasket, try a full rad flush. Or just topping up the antifreeze or adding some water wetter.
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Monday, July 27th, 2020 AT 4:34 PM (Merged)

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