Overheating at an idle [Archive] - GrandAmGT.com Forum


View Full Version : Overheating at an idle

08-06-2009, 01:20 PM
So when i was driving today i stopped at timmies and let my gf go in and get coffee when i was idleing at park on level ground, it overheated too 130! Immediatly i shut down the vehicle and let it rest.

My ga's a 99 GT 2 door. Does anyone elses do this at an idle the coolant im using is ACDelco long lasting coolant. Cars only got 160 000 k on it and i just replaced the intake gaskat.

Mike Jung
08-06-2009, 01:29 PM
No, can't say I have.
I haven't seen my GA overheat.
Especially after getting Mark from MP Racing to retune my PCM. The engine coolant fans come on earlier now.

Have you checked the coolant level, after doing the intake gaskets ?
Your coolant could be low in level.

Do both engine coolant fans come on; & on high speed ?

Maybe your thermostat is stuck closed ?

08-06-2009, 11:51 PM
No the coolant level isn't low, -I just changed the oil how much did it cost for him to re program your pcm? I havnt checked the fans yet, that would be my best guess too because when I start driving it starts cooling down. So far this has happened to me 3 times once to the point where the car just turned off. Wich scares me cuz I don't wanna warp a head.

When abouts the fan should turn on when at idle and driving?

Mike Jung
08-07-2009, 12:05 AM
You have to get it fixed 1st before you go tuning/changing the PCM.

MP Racing - 1999-2005 Grand Am V6 Custom PCM (http://www.mpracing.org/store/index.php?act=viewProd&productId=92)

I had him do mine in-person when I was in the Chicago area last year.

The PCM commands Low Speed Fans ON under the following conditions:

The engine coolant temperature exceeds approximately 106C (223F).
The A/C refrigerant pressure exceeds 1310 kPa (190 psi).
The vehicle is shut off when the engine coolant temperature is greater than 140C (284F) and system voltage is more than 12 volts. The fans will stay ON for approximately 3 minutes.

The PCM commands High Speed Fans on under the following conditions:

The engine coolant temperature reaches 110C (230F).
The A/C refrigerant pressure exceeds 1655 kPa (240 psi).
When certain DTCs set.
Why did GM have it programmed to let the engine coolant temperatures get so high ?
Emissions ?

Surely, it can't be good for your engine's fluids ?

Note: The stock (3400 V6 engine) thermostat is 195F/90C.

Mark from MP Racing had my PCM tuned for...
Low Speed Fans commands:
ON: 212F/100C
OFF: 207F/97C

High Speed Fans commands:
ON: 221F/105C
OFF: 216F/102C

So much better driving in traffic jams.

Thanks, Mark :)

08-07-2009, 06:24 PM
So the fans didn't turn on at all in the 15 min I ran it then I gave up but for most of that I had the hood open cuz I'm retarted then I realized and **** it for about 6 mins and they still didn't go on? Should I re try hood closed completely?

08-07-2009, 10:20 PM
Check to make sure your fans are working. I believe if you turn the on the A/C the fans should come on.

08-10-2009, 03:21 PM
Ok so tried the ac thing today, since I bought the car the ac hasn't worked but I did turn it on, and the fans did not start.

08-12-2009, 11:13 PM
Anyone? Little help appreciated!

08-16-2009, 11:24 AM
Ok so tried the ac thing today, since I bought the car the ac hasn't worked but I did turn it on, and the fans did not start.

i have the same problem. my fans dont come on at all. check to make sure your fans work by unplugging your engine temp sensor and starting the engine. the fans should kick on to full speed within 5 mins. i have yet to solve this problem. ive changed my t-stat,coolant, and my engine temp sensor. i have been trying for about 3 mos to figure it out.

08-16-2009, 12:26 PM
just take it to your dealership and let them fix it

08-16-2009, 12:29 PM
anyone ever think about the water pump?

08-16-2009, 12:58 PM
what would a water pump have to do with fans turning on

08-16-2009, 01:25 PM
if your a/c doesnt work, the clutch is not going to engage, so i dont think turning on the a/c would do anything anyhow

my car idles at 210 or above with a 180 thermostat and the fans going

08-17-2009, 01:59 PM
what would a water pump have to do with fans turning on

im talking about running warmer then normal not the fans.

my ga is black and if i sit in place for a lil while it gets up to a lil above 200 F but thats during the summer. once i get moving its perfectly fine. and i have a 180 thermo but my fans work fine, but ive also tuned them to turn on earlier

08-18-2009, 06:56 PM
So tested it again today heated up to 130 red light on, no fans at all.

08-18-2009, 07:18 PM
i,ve solved it bro. i took it to a mechanic with computer progammer and he turned my fans on with it. he said the pcm isn't telling the fans to turn on. so i took it to the dealer and they said i needed to have it reprogamed or flashed. so thats your solution rite there

08-18-2009, 08:10 PM
That's the plan since I just got my intake gaskat replaced I'm gunna say they worked before. That's tmrw tho.

08-18-2009, 08:25 PM
That's the plan since I just got my intake gaskat replaced I'm gunna say they worked before. That's tmrw tho.

could be several things and your idea is the best.How long ago was this intake gasket fiasco performed? I only ask because most shops honor a 12k or 12month warranty on thier work ESPECIALLY dealerships

If your pump is shot it won't move the coolant out thru the motor or the out thru the radiator when the t. stat is open. you could also be low on coolant and there is an air pocket in the system that hasn't been bleed thoroughly. temp sensor could be bad as well you do have 160k on that biatch. let us know what they came up with.

08-19-2009, 12:35 PM
It was just a few weeks ago. And this dealerships pretty good.

But there is 160 k on it just hit 160 actually

08-19-2009, 12:44 PM
Anyone? Little help appreciated!

Power to the fans? If not, relay, fuse or Coolant temp switch.

08-21-2009, 11:19 AM
k so heres the deal, because my ac doesnt work, the ac compresser isnt working, witch is creating a short in the relay so my ac is blowing the fuse and that means the fan wont turn on,

solution ether fix the ac compressor or disconnect it so the fuse stays in tact.

anyone have an ac comresser that they want to sell that works!?!!?

08-23-2009, 07:35 PM
wait they are 2 diff circuits. did the dealer tell u this?

08-24-2009, 09:33 AM
Just unplug the AC compressor til you get it fixed. That's what I did, and it didn't engage the compressor and I had no problems.

My Car is just barely starting to heat up now. It normally stays about 1-2 notches below midway, and now its averaging about 1 notch above. I have a 180 tstat in the shed I'm gonna throw in there and then replace the temp sensor. I may also have to check the relay, and fuses, but haven't been able to get out there and troubleshoot to see exactly why its doing it. Also been getting bad gas mileage since the temp has risen a little.