No heat when going fast

JORDAN_LESLIE

MEMBER
PONTIAC SUNFIRE

I have a 96 Sunfire.
In the summer my car is fine and in the winter it heats up great and blows hot air if I'm driving under 35k. As soon as I hit the highway and speed up, I lose all my heat and it only blows freezing cold air.
It has a bra but I've even tried cardboard in front of the radiator and it does nothing.
I had the head gasket replaced 3 years ago and when it started doing this I brought it back in and they replaced the thermostat. But still no heat.
Any ideas on what the problem could be? I would appreciate any suggestions, because I'm at a loss.

2 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Could be a bad thermostat and clogged-up heater core or a blend door/mode.

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Tuesday, November 20th, 2007 AT 2:34 AM

ELIZABETH LUCKE

MEMBER
2 POSTS

*****
I have a 97 with 182900 miles, 2.2 that overheated in April 04. I had the water pump replaced and have monitored that situation consistently. Now as of this fall, I have noticed that the heat registers barely above 100 especially if I am doing over 50. Even if I sit and idle, like in a drive thru, it doesn't get into the normal range. Am I looking at a huge expense to fix this problem? I am a single mom on a microscopic budget. Also, my A/C hasn't worked in years and won't hold a charge. Should I just get another used car at this point and can I find these parts in the junk yard? Thanks for any help you can give.
Elizabeth