2006 Grand Prix Overheating and Low Cabin Heat?

120

Asked by officerdave Sep 20, 2013 at 08:41 PM about the 2006 Pontiac Grand Prix GT

Question type: Maintenance & Repair

I have a 2006 Grand Prix Gt 3.8 Supercharged. I was gettin glow cabin heat so I flushed out the rad and heater core added new Dexcool mixed 50/50 and the engine started overheating and still low cabin heat. I have changed the thrmostat and still the same low cabin heat unless the climate control is at max and still running very hot almost in the red.

42 Answers

200,925

Was it overheating before you flushed it? If not did you properly burp the air out of the system after you flushed it?

5 people found this helpful.
120

N ot wasn't overheating before and I burped it several times and bleed it off threough the valve on the top of the water neck.

2 people found this helpful.
200,925

Oh ok. Sure sounds like it might still have some air trapped in it.

1 people found this helpful.

Look under hood for evidence of a prior overheat...someone fixed the leak (probably with a buck knife cutting the bulbous portion off) and refilled with tap water or hose water causing corrosion and you engine getting buggered up and the radiator gettin' choked...use a 14 dollar thermal spot gun to measure the hot spots...then replace the radiator...I'm sorry its a pain in the ass on your model but must be done if choked with rust~...you could try flushing if you could recover into five gallon buckets for environmentally disposal recycling...even if laden with rust, can pull the ethylene glycol out of there and make money off of that~ New radiator....coolant flush and fresh 195 thermostat...cross your fingers that coolant gets to critical areas after that....sell it to a kid when that doesn't work~

120

I have tried burping it many times and ran it with the bleeder valve open as well a few times and still no change

1 people found this helpful.

you could check the engine temperature sensor to make sure the fans will come on when it comes up to operating temp...a fuse or relay might be causing the overheat~

1 people found this helpful.
120

I have owned the car since new and have taken very very good care of it. Other than thjis problem the car is in fantastic condition not a mark on it

1 people found this helpful.
200,925

And overflow resivoir is filled to proper level?

4 people found this helpful.
200,925

And the cap is in good shape? A bad cap can cause one to overheat.

1 people found this helpful.
200,925

Not to change subject but with the cabin heat. Does the air blow good and strong or feel weaker than it use to?

4 people found this helpful.

coolant flow is good...measure with a fourteen dollar lazer thermal gun...the fans come on at 195...where's the problem?...choked radiator...measure the hot spots with a lazer gun~

200,925

Are your radiator fans coming on when it starts to overheat?

1 people found this helpful.
200,925

Oh and with bleeder valve open is coolant coming out the bleeder?

Best Answer Mark helpful
120

yes there is coolant coming out of the bleeder and the fans stay on

1 people found this helpful.
120

the engine runs very hot in traffic almost in the red the heater fan blows hard but only have cabin heat if I turn the climate control to 30 or 32 which is max other than that I have cool air and a hot running engine. I have no idea wha tis causing this

3 people found this helpful.
120

I have checked it and it is in correctly it is a T stat direct from GM

1 people found this helpful.
200,925

Have you ever put anything like stop leak in it?

3 people found this helpful.

if feeling particularily vicious could connect the end of the heaterbox hose to a garden hose and capture the other side in five gallon buckets...this would blast out any corrosion and assure good flow through the heater core~...be sure to stop up the other side with a plastic bag and rubber band~

1 people found this helpful.
120

No I have never touched the rad before. I have flushed it out using the cleaner and now it overheats. And still very low cabin heat unless the climate control is turn to max

1 people found this helpful.

There is a vacuum operated valve to shut flow to core on/off. Maybe stuck? Vacuum hose off?

6 people found this helpful.

And that vacuum leak, IF it is, can cause a lean fuel trim and heat up and engine...? Guessing.

1 people found this helpful.

...it's the cleaner and subequent failure the cause for concern here...am suspicious of Techron(tm) effect on fuel pressure regulators....did they ever do a check-see to see if there is significant deterioration of the diaphragm materials used?

1 people found this helpful.

Naw the ECU would be able to correct the fuel/air trim if it's just a 1/4" hose leak

1 people found this helpful.
200,925

Sounds like davidh25 might have this one figured out.

1 people found this helpful.

additive designed to "CLEAN YOUR FUEL" often cleans the parts that are needed like the diaphragms that come in contact with it and hyper-sensitive gasoline seals~

--- "flushed it out using the cleaner and now it overheats" has got me on my hind legs...trying to wrap my head around just how this may have gone awry~? `

1 people found this helpful.

Shell and Exxon/Mobil have detergents...that is why I always pay a bit more for Shell. One station. They sell a LOT and it's always fresh, and often a police car there filling up, the City cars (all four of them) and County both...a dozen or so deputies cars for the surrounding countryside

1 people found this helpful.

...yeah, officerdave---was there an increase in idle speed when the heat quit working? change the butyl rubber hoses (chewing gum with coal tar added) with silicone that will never fail or leak~

1 people found this helpful.

a spool...one at a time for every single vacuum connection under the hood may prove beneficial as the butyl rubber ones WILL crack and leak without you recognising it~

1 people found this helpful.
120

I have an 06 Grand Prix 3.6 and it start running hot is not smoking jUs cut off a sudden..its say cut AC off to protect engine.. I took the radiator cap I changed the thermostat it was a lot of rusty on stuff in the radiator there's no water or anything leaking from nowhere do you know what is wrong thank you

12 people found this helpful.
20

I had the same problem with my 2007 grand prix gt supercharged changed thermostat water pump you name it bled the lines it still ran to the overheating point!!! Then we found that the coolant bypass elbows were cracked and leaking just enough not to be seen but to make my car run very hot. We got metal ones put them on bled the system and things have been fine since!!! These cars I read are notorious for those elbows cracking!!!

2 people found this helpful.
110

My 05 Grand Prix started overheating and water was drainng through the reservoir tank I thought it was the heads or water pump, long story short it was the radiator cap about $10 and problem solved it's worth to try (hope this can help )

1 people found this helpful.

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