1995 Pontiac Bonneville Little to no heat

Tiny
DLUTZ1983
  • MEMBER
  • 1995 PONTIAC BONNEVILLE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 190,000 MILES
I just recently bought a 95 Bonneville when I drove it home it had no heat what so ever. I replaced the thermostat, as well as a flush of the coolant system. If I crank the temperature up to 90 I get a little heat, but as soon as I go to turn it down I loose all heat and starts to blow cold. I have noticed that my car never warms up above 195 could this be the problem, and is it cause by a coolant temperature sensor?
Thursday, October 8th, 2009 AT 12:35 AM

6 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Feel both hoses that come from the heater, they shot both be VERY hot so be careful, if the outlet hose is cool or cold, the heater core is clogged with gunk, either replace the core, or you can attempt to backflush it, but cores are tough to clean out.
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Thursday, October 8th, 2009 AT 1:48 PM
Tiny
DLUTZ1983
  • MEMBER
  • 3 POSTS
Checked the hoses both are hot. I do get heat, but it comes and goes. If I have cold air and shut the car off, then turn it back on I get heat. Then sometimes the heat wont work at all.
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Thursday, October 8th, 2009 AT 6:16 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Check the temeratur blend door, and actuator for it.
Sometimes the shaft rusts and wont turn, other times the actuator, or vacuum servo goes bad. Also if it has a heat control valve, it will be on inlet heater hose, the valve can go bad or the vacuum line to it leaks. It would help if I knew what model Bonneville this is and if it has auto or manual a/c?
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Saturday, October 10th, 2009 AT 10:08 AM
Tiny
DLUTZ1983
  • MEMBER
  • 3 POSTS
1995 Bonneville Se with Electronic Heat control
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Saturday, October 10th, 2009 AT 10:48 AM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
You can try adjusting the air mix valve link, here's how, and test the vacuum connector too!
AIR MIX VALVE LINK Remove glove box. Disconnect link rod from output crank on programmer. See Fig. 1 . Start engine. Set control panel for maximum heating. Allow at least 45 seconds for programmer to reach full heating position. Move air mix valve crank to maximum heat position, hold it in this position, and snap the link rod onto the output crank.


https://www.2carpros.com/forum/automotive_pictures/62217_air_mix_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_vac_test_1.jpg

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Saturday, October 10th, 2009 AT 11:21 AM
Tiny
DAMON6222010
  • MEMBER
  • 3 POSTS
Just thought that I would let you know that I had the same problem with my 1996 bonneville. It turned out to be air in the cooling system. All I had to do was hit the bleeder near the thermostat and that fixed the problem.
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Friday, October 30th, 2009 AT 8:19 AM

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