why does my car still blow cold air after changing the thermostat?

Asked by Oct 14, 2012 at 05:11 PM about the 2005 Chevrolet Monte Carlo LS

Question type: Maintenance & Repair

my car started blowing cold air when I took the radiator cap off the flued was thick brown sluge. so i flushed it twice and put a new thermosta in it but it still blows colair.

8 Answers


The cooling system in these cars must be bled. That is all the air removed after the cooling system is serviced. Set the heating controls to full heat & open the bleeder screw, which is probably located at or near the thermostat housing until coolant flows smoothly out. Leave the screw open for an additional 10 seconds & you should be all set. HTH. -Jim

5 of 5 people found this helpful.

You probably flushed it in the wrong direction and clogged it up even worse.

1 of 1 people found this helpful.

does the engine temperature get to normal, or very close to it...if you ask me, even a clog in a cooling system means the engine runs hotter, not producing cool air, however there are other more common things causing this...one would be to flush the HEATER CORE, not radiator, but still not likely, rather an actuator door, motor in the dash is malfunctioning, gm also had issues with the physical dial/button on the console going bad that controls temp....message me if i can help further

9 of 9 people found this helpful.

A clogged heater core won't cause any noticeable change on the gauge.Check the hoses going to the heater core, they should be close to the same temp as the engine if both of them are cool to the touch then there is a clog

2 of 2 people found this helpful.

This is a problem with 3.4 and 3.5 engines.All above can be problems. Most likely go for easy one first. When this cars run low at the filler tank they suck in air and cause air pockets. Try bleeding air out at thermostat bleeder.. let it run for about 30 seconds till it runs constant at bleeder then give it a try. Still may need flushed. I use plain old Prestone yellow. Same stuff just cheaper. All same ingredients as the GM. Flush till clear and you won't have a problem. These cars are a pain in the ass to work on. P.S. DON'T BUY THE 50/50 CRAP. IT IS NOT 50/50!!!!! Go pure then mix your own 50/50 with DI water, i.e. ironing water. Has no iron or metal contaminants. hope that was some help. good luck

1 of 1 people found this helpful.

just changed my thermostat after my 2002 monte carlo ls would get very hot. now my motor is good but my heat for the cab is very low unless i rev it up then it gets good and hot..thank you for this post now i am going to bleed off the air i had no clue i needed to do this!!

1 of 1 people found this helpful.

put in new thermostat, worked one day, now antifreeze is not staying in jug, don't know where it is going, blowing cold air again

4 of 4 people found this helpful.

Have a 98 monte carlo having problems with heat. The heater is blowing out nothing, but cold air. My tempature gage will sometime hit 260 and cause my heat light to come on. Please can you help with this problem.?

Your Answer

Monte Carlo

Looking for a Used Monte Carlo in your area?

CarGurus has 966 nationwide Monte Carlo listings starting at $3,786.


Chevrolet Monte Carlo Experts

  • #1
  • #2
    Tom Demyan
  • #3
    John Saffrahn
View All

Related Models For Sale

Used Chevrolet Impala
361 Great Deals out of 27,033 listings starting at $1,000
Used Dodge Charger
238 Great Deals out of 33,021 listings starting at $495
Used Ford Mustang
278 Great Deals out of 38,285 listings starting at $1,995
Used Pontiac Grand Prix
1,904 listings starting at $3,000
Used Chrysler 300
294 Great Deals out of 19,006 listings starting at $1,999
Used Chevrolet Corvette
93 Great Deals out of 15,625 listings starting at $4,500
Used Chevrolet Malibu
601 Great Deals out of 48,048 listings starting at $1,800
Used Chevrolet Silverado 1500
2,203 Great Deals out of 149,934 listings starting at $1,499
Used Chevrolet Tahoe
634 Great Deals out of 37,190 listings starting at $795
Used Buick Regal
92 Great Deals out of 4,167 listings starting at $3,500
Used Nissan Maxima
232 Great Deals out of 17,857 listings starting at $1,500

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.