Overheating in the winter with no heat coming.

Tiny
MELANIELYNN1
  • MEMBER
  • 2006 CHEVROLET COBALT
  • 4 CYL
  • 2WD
  • MANUAL
  • 50,200 MILES
I have a 2006 Chevy Cobalt LS. This summer it was overheating on the days it was really hot out. I have not had any trouble since the weather cooled down (naturally) until today. I live in MN and the temp got down to 20 below zero last night. I started my car about 15 min befor eI had to leave. When I got in my car the temp was at 190 but the heat was blowing out freezing cold air. My boyfirend took it for drive after I took his car to work and told me the temp hit 259. The coolant resevoir has fluid in it. Any thoughts on what might be going on?
Friday, January 21st, 2011 AT 3:13 PM

7 Replies

Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
Could be a thermostat, although you should get some heat.

Quickly touch both heater core hoses, if one is hot and one cold, then heater core is blocked, if both cool, then thermostat or possible waterpump.
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Friday, January 21st, 2011 AT 3:17 PM
Tiny
MELANIELYNN1
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Thanks for the help. Unfortunately I am at work now and my car is at home. But I thought the same thing about the thermostat. I was under the impression (I am not an expert or anything near one. I know tibits here and there about cars)that even if your thermostat isnt opening that since the enogine was warm that it should be still putting out heat if the blower is working.

What would cause a heater core to be blocked?
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Friday, January 21st, 2011 AT 3:30 PM
Tiny
MMPRINCE4000
  • MECHANIC
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Debris is cooling system can block core, although it would be unusual in a 2006.
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Friday, January 21st, 2011 AT 3:37 PM
Tiny
MELANIELYNN1
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  • 4 POSTS
This will be really stupid but I have to ask. Could it be due to the fact that I am WAY ove ron my oil changes?
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Friday, January 21st, 2011 AT 3:38 PM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
Oil will sludge after many miles and heat cycles, But it would clog oil pump and engine would begine making noise.

Hopefully just a thermostat, also check condition of coolant.
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Friday, January 21st, 2011 AT 3:43 PM
Tiny
MELANIELYNN1
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  • 4 POSTS
Ok. I will work on these things. I cant tell you how much I appreciate your help. Unfortunately my BF isnt a mechanically inclined person (at all), but his intentions are good. So, I will be working on this stuff myself. I hopeits alright that I continue to pose questions as I go through this. I cant really afford a mechanic until I absolutely know its neccesary.
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Friday, January 21st, 2011 AT 3:55 PM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
Ask Away, although I do not come to forum everyday.

Consider a Haynes manual for reference.
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Sunday, January 23rd, 2011 AT 2:24 PM

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