No heat - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


2000-2005 Discuss your 2000-2005 Bonneville SE, SLE, and SSEi Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 12-08-2010, 09:18 PM   #1
Junior Member
Thread Starter
 
Join Date: Mar 2009
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Evilneon R/T is on a distinguished road
Default No heat

Ok, so my Bonneville will run at 200 degrees consistently, but have no heat. Air comes out, just not cold. Then magically, sometimes, the air turns hot. Car takes forever to warm up when cold and forever to cool down after driven. When the heat doesnt work, the coolant lines were a little warm and then I raced the engine a few times and the lines warmed up a lot and the heat started working. Thermostat is new, maybe the water pump? The car isn't overheating though? Possibly a bad rad cap? Opinions are welcome, Thanks!
Evilneon R/T is offline   Reply With Quote
Old 12-08-2010, 09:46 PM   #2
Senior Member
Posts like a Supercharger
 
mike9fore's Avatar
 
Join Date: Mar 2010
Location: Beltsville,MD
Posts: 181
Thanks: 0
Thanked 0 Times in 0 Posts
mike9fore is on a distinguished road
Default

Quote:
Originally Posted by Evilneon R/T View Post
Ok, so my Bonneville will run at 200 degrees consistently, but have no heat. Air comes out, just not cold. Then magically, sometimes, the air turns hot. Car takes forever to warm up when cold and forever to cool down after driven. When the heat doesnt work, the coolant lines were a little warm and then I raced the engine a few times and the lines warmed up a lot and the heat started working. Thermostat is new, maybe the water pump? The car isn't overheating though? Possibly a bad rad cap? Opinions are welcome, Thanks!
Sounds like the heater core....did you flush the coolant when you installed the thermostat? there maybe an air pocket in the cooling system...
mike9fore is offline   Reply With Quote
Old 12-08-2010, 09:57 PM   #3
Junior Member
Thread Starter
 
Join Date: Mar 2009
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Evilneon R/T is on a distinguished road
Default

I flushed the system throughly trying to get the dex-crap out and ran it a while open to let the air out. I even flushed just the heater core itself. It just seems that the coolant isn't circulating. The car doesn't overheat though. Does the car have a factory heater core bypass? Maybe thats the problem?
Evilneon R/T is offline   Reply With Quote
Old 12-09-2010, 12:13 AM   #4
Retired Senior Admin

Expert Gearhead
 
Danthurs's Avatar
 
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Thanks: 0
Thanked 16 Times in 13 Posts
Danthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to all
Default

The heater core could be plugged. You could remove the lines and try to flush it.
Danthurs is offline   Reply With Quote
Old 01-16-2011, 11:10 PM   #5
Junior Member
Thread Starter
 
Join Date: Mar 2009
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Evilneon R/T is on a distinguished road
Default

Ok, flushed cooling system and made sure all air was out. Heat core was flushed, antifreeze added. The heat stayed ice cold until the car got up to about 205 degrees then the temp dropped to about 190 and the heat suddenly got really hot. Is my thermostat not opening soon enough to circulate warm air through the system? The car doesnt overheat, but it just seems the thermostat never opens sometimes. Let me know.
Evilneon R/T is offline   Reply With Quote
Old 01-16-2011, 11:47 PM   #6
Retired Senior Admin

Expert Gearhead
 
Danthurs's Avatar
 
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Thanks: 0
Thanked 16 Times in 13 Posts
Danthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to all
Default

Stock temp is 190, so it all sounds about right.
Danthurs is offline   Reply With Quote
Old 01-17-2011, 01:49 AM   #7
Junior Member
Thread Starter
 
Join Date: Mar 2009
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Evilneon R/T is on a distinguished road
Default

yeah but mine runs constantly at 200-205ish. Rarely does it go down below 200. So the car can be at 205 with no heat. It almost seems like the thermostat isn't always opening like the heat rating on it is too high.
Evilneon R/T is offline   Reply With Quote
Old 01-17-2011, 02:11 AM   #8
Senior Member

True Car Nut
 
sseidriver97's Avatar
 
Join Date: Mar 2010
Location: Portage mi
Posts: 7,124
Thanked 3 Times in 3 Posts
sseidriver97 is on a distinguished road
Default

Pressure test it to see if there are any unseen/internal coolant leaks..My dads truck runs fine and at temp with no heat..It has a cracked head/block or a blow head gasket...I havent torn the motor down yet to see
sseidriver97 is offline   Reply With Quote
Old 01-17-2011, 11:10 PM   #9
Senior Member
Posts like a Supercharger
 
Join Date: Sep 2005
Posts: 195
Thanks: 0
Thanked 6 Times in 5 Posts
imidazol97 is on a distinguished road
Default

Have you tried running the motor at 2500 rpm for 10-15 seconds AFTER the motor is completely warmed up after driving 10-15 minutes? Then repeat that 4 more times. That was the method for clearing air out of the heater core in the Factory Service Manual. I do it with the car slightly uphill hoping it helps the air work it'* way out of the heater core.

Then bleed the air at the thermostat housing.

Does the upper radiator hose get very warm after 10-15 minutes when the thermostat opens? It should be so hot you can't hold your hand on it more than few seconds.

Is the thermostat in correctly? Sorry to ask, but I think we should check. Is the thermostat in the groove in the middle of the rubber ring which is the seal?

Is the radiator full with the motor running above idle? Fill it then close the cap while someone idles the engine above normal idle.
imidazol97 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Runs hot - no heat - then temp drops and heat works?? atp 2000-2005 15 12-16-2009 07:46 AM
Heat blowing cold + flashing heat controls after 20 sec chilump 1992-1999 23 02-08-2007 11:48 AM
Anyone here heat with oil heat? I have questions? h1081dan Lounge 3 11-14-2004 05:22 PM
Headligts on...Stero/heat display lights off 0Tick 1992-1999 8 12-02-2002 12:15 AM
Exhaust heat shield? Dr. Moomoo 1992-1999 2 12-31-1969 08:00 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 12:51 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.