PontiacBonnevilleClub.com

As the title states, I've got little to no heat. Car comes to operating temp and the heater hoses are hot as well as the upper/lower radiator hoses. I've manually taken all the blend door off except for the inlet actuator (Functions the recirculation/fresh air door?) and moved them manually with minimal heat. Currently I have the motors unplugged and set to defrost and heat on both sides. The motors are not moving themselves so I assume the body control module or what not is toast. Any help would be appreciated. Winter is right around the corner lol

Post I was referring to for the acutators.
http://www.pontiacbonnevilleclub.com/fo ... 47886.html

Before you dig real deep into the electronics/ electrical, you might want to consider doing a radiator pressure test. Seems every time I have a poor heating issue it has come down to a a weak leak in the cooling system, to include a water pump and a LIM gasket. I know you stated the hoses are hot to the touch, but that may not be enough to say the cooling system is fully functional. Pressure test takes just a few minutes.

MikeKerr wrote:Before you dig real deep into the electronics/ electrical, you might want to consider doing a radiator pressure test. Seems every time I have a poor heating issue it has come down to a a weak leak in the cooling system, to include a water pump and a LIM gasket. I know you stated the hoses are hot to the touch, but that may not be enough to say the cooling system is fully functional. Pressure test takes just a few minutes.

I will say my water pump gasket weeps a little coolant here and there, nothing substantial though.

If both heater hoses are really hot then the issue is the blend door actuator.

crash93ssei wrote:If both heater hoses are really hot then the issue is the blend door actuator.

Had same problem last year. Was exactly that after checking everything else first. I didn't want to believe it was that.

azu wrote:

crash93ssei wrote:If both heater hoses are really hot then the issue is the blend door actuator.

Had same problem last year. Was exactly that after checking everything else first. I didn't want to believe it was that.

Referring to the link I posted in my first comment, which actuator? The only one I haven't messed with is the "Blower motor actuator".

It may be a long shot but check your coolant level. Remove your radiator cap, don't assume it's full checking the recovery tank.

AJT2004 wrote:It may be a long shot but check your coolant level. Remove your radiator cap, don't assume it's full checking the recovery tank.

I'll check it tomorrow when I get a chance. Also check the last blend door actuator.

Little update.

I checked the radiator and it was full, topped off the reservoir. Also removed the last actuator and manually moved everything by hand. While there is a little heat, its not what it should be. And there is definitely a difference when I manually switch the doors by hand between heat or cold air.

Sometimes the heat "feels" like it will suddenly get warm then back to cool. The operating temps aren't doing anything weird. Kind of at a loss. Thinking maybe a partially clogged heat core or something? Again, when I checked the hoses they were all hot.

Any help would be appreciated.

Take a second look at doing a pressure test. Very easy to do and will eliminate a whole bunch of possible issues if coolant system shows no leaks. Every GM vehicle I have owned (Bonneville, Grand Prix, S10s, Bravadas) have had issues with not enough heat, it has always come down to a clogged heater core, water pump, elbow leak, of LIM gasket leak. A pressure test will eliminate all of those possibilities except a clogged heater core.

MikeKerr wrote:Take a second look at doing a pressure test. Very easy to do and will eliminate a whole bunch of possible issues if coolant system shows no leaks. Every GM vehicle I have owned (Bonneville, Grand Prix, S10s, Bravadas) have had issues with not enough heat, it has always come down to a clogged heater core, water pump, elbow leak, of LIM gasket leak. A pressure test will eliminate all of those possibilities except a clogged heater core.

Looks like this is the next step. Thanks!

Not sure if a clogged/dirty cabin filter could be the source of your heating woes but it wouldn't hurt to look as it's easy to do.

garagerog wrote:Not sure if a clogged/dirty cabin filter could be the source of your heating woes but it wouldn't hurt to look as it's easy to do.

There is no filter installed ATM. Thanks for the response though. -

Swapped in another thermostat and got the car up to temp with no change tonight. When I got back I noticed the rear heater hose (One closest to the firewall) was barely hot compared to the other one. Also noticed the bottom radiator hose was not as hot as the upper. Do I have air trapped in my system or does it sound like the heater core is clogged? Still haven't pressure tested the system yet just trying to gather more info.

hi, might be good idea to drain/flush and refill/bleed system

please bleed before you flush and maybe you get lucky

from a cold start, with rad cap off and bleed valve open and heat on full blast to hottest setting.
let idle... when temp gets to 90c/200f, you will see the level drop in the rad cause thermostat opens
at this time you top off rad and cap it. close bleed valve when you see a steady stream of fluid.

see if your heat is back...good luck!!

96 SSEi wrote:hi, might be good idea to drain/flush and refill/bleed system

please bleed before you flush and maybe you get lucky

from a cold start, with rad cap off and bleed valve open and heat on full blast to hottest setting.
let idle... when temp gets to 90c/200f, you will see the level drop in the rad cause thermostat opens
at this time you top off rad and cap it. close bleed valve when you see a steady stream of fluid.

see if your heat is back...good luck!!

I'll give that a shot. Would you recommend on level ground or at a incline?

level ground is preferred but if there is an incline, be sure the rad is the highest point

Heater core man. Most likely.

DCJREDLINE wrote:Heater core man. Most likely.

It's beginning to look that way. If bleeding the system without the rad cap off doesn't do it I'll probably go grab one from the junkyard.

I would strongly suggest buying a new heater core. They're relatively inexpensive and given the difficulty to install I would not take a chance with a used one.