heater only blows cold

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Oct 20, 2005 | 08:26 AM

rez-t/a

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Staging Lane

Joined: Apr 2005

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From: Shiprock, NM

heater only blows cold

I have a 98 Trans Am. Its starting to get cold here in NM and when I go out to start my car to let it warm up for about 5 to 10 mins it wont blow hot just cold. All summer long my cars temp never went above 165 with a new 195 thermostat. my drive to work is about 20 mins and still the car just stays at 165. I searched for a simular prob like this and found that the A/C compressor is suppose to be on with defrost mode set but when it was on both of my fans are also on.

The weired thing is one time in the middle of the day I let my car sit while running and the temp went to 210 so I turned on the heater and still it blew cold. If anyone has any ideas please let me know. Thanks for any info you could provide!!!

Oct 20, 2005 | 08:56 AM

jkichline

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From: Bethlehem, PA

It sounds like a thermostat issue but you said that you put a new one in... Its weird that it doesn't regulate to 195° though... are you sure its a 195° stat?

Couple things to check....

1) Fluid level and make sure the system does not have any air... Maybe the fluid is not making it to the heater core. If you've ever replaced the fluid, you need to bleed the system properly. Many TA owners forget to do this (including myself).
2) when you turn your temperature controller to hot... make sure that the **** is actually turning the shaft behind the **** to hot.... You should be able to pull the **** straight off and see what position it is in...
3) It could also be a vacuum problem as the climate control is a vacuum system. I'm not sure how to troubleshoot that part....

By the way, when your air compressor runs, your radiator fans are supposed to also be running.

Oct 20, 2005 | 10:07 AM

rez-t/a

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Staging Lane

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From: Shiprock, NM

hey thanks!! you right i never blead the system. how is that done? so i need to check and try that. The thermostat was a 195, i made sure.

okay now, is the AC suppose to be on in the morning when i do turn on my heater? cause if the fans are on wouldnt that keep it from getting to the right temp.?

Thanks again for your help!

Oct 20, 2005 | 11:17 AM

jkichline

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From: Bethlehem, PA

Here's a link where we are talking about bleeding the system. If you have a haynes or chilton, it would be a good idea to read that over.
Bleeding
When you start the car in the morning, the fans should run ONLY if the compressor is running. The compressor only runs for air conditioning or defrost. There is a setting for heat and defrost which will also run the compressor. However, for heat ONLY, the compressor should not be running so your fans shouldn't be running either, unless your around 210° or higher.

Oct 20, 2005 | 03:12 PM

rez-t/a

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Staging Lane

Joined: Apr 2005

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From: Shiprock, NM

okay thanks again I'll do some more looking over and see what I find.

Oct 23, 2005 | 05:05 PM

rez-t/a

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Staging Lane

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From: Shiprock, NM

I got the cooling system blead I temp stays around 170 and thats it. I let the car heat up enough to have the fan come on(210+) and still the heater still blew cold. any other Ideas why my heater blows cold?

Oct 23, 2005 | 05:59 PM

P Mack

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From: Phoenix

Did you recently do an intake manifold swap or anything like that? If so you could have forgotten to hook the vacuum line on the back of the intake back up. But then I think none of your climate controls would work right.