Overheats at idle

Tiny
JUNIORMS54
  • MEMBER
  • 2009 PONTIAC TORRENT
  • 3.4L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
If I keep rpm temperature works normal. At idle overheats way to red. Changed water pump, temperature sensor, no air in system. New thermostat, new radiator last year.
Saturday, May 4th, 2019 AT 4:17 PM

17 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Welcome to 2CarPros.

If it doesn't overheat at highway speed but does at idle and sitting, are you sure the cooling fan is turning on? If it is, did you inspect the engine block for restrictions? You have already done a lot to it. By any chance, was the OEM dexcool coolant mixed with another type? Have you confirmed if there is a head gasket issue? Was the radiator cap replaced? When driving, is the engine running properly? Have you checked for a partially plugged catalytic converter?

Here are a few links that may help. The first one reviews how to check for a head gasket issue.

https://www.2carpros.com/articles/head-gasket-blown-test

Here is a link that explains how a cooling fan works:

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

https://www.2carpros.com/articles/replace-electric-fan-motor

___________________

If there is a power loss, check this, too.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

___________________

I noted that you are beginner mechanic. Do you have a live data scan tool? If so, check fuel trims to determine if the engine is running extremely rich due to a bad fuel pressure regulator or a sensor issue. Also, if the check engine light is on, retrieve any diagnostic trouble codes and let me know what they are.

Let me know the answers to the aforementioned questions.

Take care,
Joe

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Saturday, May 4th, 2019 AT 6:06 PM
Tiny
JUNIORMS54
  • MEMBER
  • 9 POSTS
Lower intake gaskets were done. Could not tell sign of restriction. New thermostat, new water pump, new radiator cap. Heater core was done along with a few hoses and bypass. Head gasket check not performed yet. Seems to drive normal when test drive. No check engine light.
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Sunday, May 5th, 2019 AT 3:10 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
If everything is new, the cooling fans are working, none of the things I mentioned are a problem, and the block was clean, the last things are a head gasket issue or timing. Are there any diagnostic trouble codes stored? If there isn't, then I recommend the head gasket test I mentioned to confirm there isn't an issue.

Let me know.

Joe
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Sunday, May 5th, 2019 AT 6:21 PM
Tiny
JUNIORMS54
  • MEMBER
  • 9 POSTS
Performed block tester check for head gasket (twice) and fluid remained blue.
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-1
Friday, May 10th, 2019 AT 4:04 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Welcome back:

If you have a live data scanner, can you check the ignition timing for me and let me know what it is.

Thanks,
Joe
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Friday, May 10th, 2019 AT 9:11 PM
Tiny
JUNIORMS54
  • MEMBER
  • 9 POSTS
AT IDLE: AFTER 2500 RPM THEN IDLE
ABSLT/TPS(%) 21.2 ABSLT/TPS (%) 20.4
RPM 772
BARO PRS (hg) 29.5
CAL LOAD (%) 14.9 CAL LOAD (%) 13.3
MAF(LB/M) 0.49 MAF (LB/M) 0.44
MAP ("HG) 9.7
OUT TEMP (F) 59
COOLANT (F) 169 COOLANT (F) 239 fans "ON"
IAT (F) 63 IAT (F) 97
IGN ADV 17/20 IGN ADV 17.5/20
ST FTRM1(%) -2.3/0.8 ST FTRM1 (%) -3.1/0.0
LT FTRM1 (%) 20.3
ABSLOAD (%) 12.9/13.7
FUEL SYS 1 CLSD
REL TPS (%) 7.8
THROT CMD (%) 11.0
ABS TPS B (%) 20.0
ACC POS D (%) 18.8
ACC POS E (%) 9.8
EGR ERR (%) 99.2
CAT TEMP 11 (F) 739 CAT TEMP 11 (F) 777
EGRCMD (%) 0.0
EVAP PURGE (%) 15.7
EVAP VP (H2O) -0.212
CMD EQ RAT 0.999
O2S 11 (V) 0.640 +/-
ST FTRM 11 (%) -2.3/1.6
O2S12 (V) 0.870/1.865
CLR DIST (mi)($00) 0
CLR DIST (mi)($02) 5495
CLR TRPS ($00) 1
CLR TRPS ($02) 255
MIL DIST ($00)(mi) 0
MIL DIST ($02)(mi) 0
FUEL LEVEL (%) 49.0 FUEL LEVEL (%) 47.8
VPWR (V)($00) 14.542/14.642
VPWR (V)($02) 14.768/14.966
ENG RUN (m:s) 22.35 ENG RUN (m:s) 47.8
OBD 2 STAT JA/CA

*** MOVED AROUND A LITTLE TEM NEEDLE WENT TO NORMAL (FANS OFF)
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Saturday, May 11th, 2019 AT 7:12 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Welcome back:

The only thing I see out of the ordinary is the long term fuel trim (LTFT). It is indicating the engine is running lean. Interestingly, the short term (STFT) indicate normal. What makes it more interesting is LTFT is based on what is happening with the STFT. Tell me, have you checked for engine vacuum leaks that could be causing a lean mixture? A lean mixture can cause the engine to run hotter than normal. Also, are there any trouble codes?

Joe
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Saturday, May 11th, 2019 AT 6:54 PM
Tiny
JUNIORMS54
  • MEMBER
  • 9 POSTS
Will be on vacation this coming week. Will be back next week and I will see about checking for leaks.
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Saturday, May 11th, 2019 AT 7:32 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Sounds like a plan. Have a good trip.

Take care,
Joe
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Saturday, May 11th, 2019 AT 8:19 PM
Tiny
JUNIORMS54
  • MEMBER
  • 9 POSTS
Hello Joe :
Sprayed carburetor cleaner wherever I could, o change on idle. There is slight fluctuation on rpm while idling. May have to take apart lower intake again. What should I concentrate on other than gaskets? Would torque on rockers have something to do? There was codes that had to do with lean codes when we started talking. I had clear codes while resetting check engine light. Am starting to think that is going to be something really stupid, something I missed.
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Wednesday, May 22nd, 2019 AT 12:22 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Welcome back:
Honestly, if you tightened the rocker arms, I don't see how that would cause this. I'm going to add the directions for rocker arm and push rod replacement. All the pics correlate to the directions and the torque specs are included.

____________________________

Valve Rocker Arm and Push Rod Replacement

Removal Procedure

1. Remove the valve rocker arm cover(s). Refer to Valve Rocker Arm Cover Replacement - Left Side (See: Valve Cover > Removal and Replacement > Valve Rocker Arm Cover Replacement - Left Side) and/or Valve Rocker Arm Cover Replacement - Right Side (See: Valve Cover > Removal and Replacement > Valve Rocker Arm Cover Replacement - Right Side).

Picture 1

2. Remove the rocker arm bolt(s).
3. Remove the valve rocker arm(s) and the pushrod(s).

Installation Procedure

picture 2

1. Coat the ends of the push rods using prelube GM P/N 1052367 (Canadian P/N 992869) or the equivalent.

Note: The intake valve push rods measure 146.0 mm (5.75 in) in length. The exhaust valve push rods measure 152.5 mm (6.0 in) in length.

2. Install the push rods in their original location.

Picture 3

3. Coat the rocker arm friction surfaces using prelube GM P/N 1052367 (Canadian P/N 992869) or the equivalent.

Note: Shims may be required under the valve rocker arm pedestals if reconditioning has been performed on the cylinder head or its components.

4. Install the valve rocker arms in their original positions.

Caution: Refer to Fastener Caution (See: Vehicle > Vehicle Damage Warnings > Fastener Caution).

5. Install the valve rocker arm bolts and tighten to 32 Nm (24 lb ft).
6. Install the valve rocker arm cover(s). Refer to Valve Rocker Arm Cover Replacement - Left Side (See: Valve Cover > Removal and Replacement > Valve Rocker Arm Cover Replacement - Left Side) and/or Valve Rocker Arm Cover Replacement - Right Side (See: Valve Cover > Removal and Replacement > Valve Rocker Arm Cover Replacement - Right Side).

__________________________________________________________

Did you check to confirm there are no restrictions on all hoses, specifically the upper and lower radiator hose? And am I correct in thinking it runs normally other than the overheating only at idle?

Let me know,
Joe
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Wednesday, May 22nd, 2019 AT 7:08 PM
Tiny
JUNIORMS54
  • MEMBER
  • 9 POSTS
Will re-do job again and I will keep special attention to your recommendations. Correct on last question.
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Thursday, May 23rd, 2019 AT 7:34 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Welcome back:

Let me know the outcome and I will watch for your reply.

Take care,
Joe
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Thursday, May 23rd, 2019 AT 4:28 PM
Tiny
JUNIORMS54
  • MEMBER
  • 9 POSTS
Mr Joe,

I sent vehicle to dealer and they was able to tell me what went on. No 1 I had replaced a couple of heater hoses (did not use original) and I overlooked the fact that they stayed higher than suppose to. In turn it created air bound that I thought was not there. Learn from stupid mistakes. Happy to say they have found and fix problem. Also found out that aftermarket thermostat can give you problem as to when it opens/closes (temperature wise). Has been a learning experience. In time will put everything original. Thanks for dealing with me.
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Monday, July 1st, 2019 AT 10:37 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Welcome back:

I'm glad to hear you got to the bottom of the problem. Interesting how simple things can cause such problems. Regardless, I wish I could have helped more. You take care and let me know if you have questions in the future.

Joe
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Monday, July 1st, 2019 AT 8:41 PM
Tiny
JUNIORMS54
  • MEMBER
  • 9 POSTS
Hello Joe,

After dealer mechanic and few dollars quick diagnosis and burping only lasted couple of days. So I shorten heater hoses and replaced stations with access Delco brand and still. Did little homework again and came up with one more desperate answer, Coolant tank.
I undid hose from opposite end to my surprise tank did not empty. Took whole tank apart, found sludge and a 1/2" sleeve inside tank and hose. Clean and back together and held good even with A/C on. It was causing bubbling/gurgling from heater core. Hopefully somebody else can use this information. Thanks again
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Tuesday, July 9th, 2019 AT 1:16 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Welcome back:

Interesting. I don't think I've seen one clog. Regardless, it makes perfect sense. And thank you for posting that. I know it will help someone.

Take care and you are always welcome back.

Joe
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Tuesday, July 9th, 2019 AT 7:14 PM

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