Cooling fan not turning off issue
04-21-2021 | 05:11 PM
#22
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Joined: 01-23-2009
Posts: 25,339
From: Fredericksburg,VA
I am not misunderstanding. Unless you are leaving something out yours is not involved.
TSB 08-06-04-001b is attached.
As RJ was saying: an exhaust leak into the gasses expand more than coolant pushing coolant out then the gasses don't retract as much as coolant so the coolant doesn't get sucked back in.
TSB 08-06-04-001b is attached.
As RJ was saying: an exhaust leak into the gasses expand more than coolant pushing coolant out then the gasses don't retract as much as coolant so the coolant doesn't get sucked back in.
04-21-2021 | 05:30 PM
#23
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Member
Joined: 06-26-2017
Posts: 83
From: Los Angeles
I am not misunderstanding. Unless you are leaving something out yours is not involved.
TSB 08-06-04-001b is attached.
As RJ was saying: an exhaust leak into the gasses expand more than coolant pushing coolant out then the gasses don't retract as much as coolant so the coolant doesn't get sucked back in.
TSB 08-06-04-001b is attached.
As RJ was saying: an exhaust leak into the gasses expand more than coolant pushing coolant out then the gasses don't retract as much as coolant so the coolant doesn't get sucked back in.
I will swap in a good tstat today when I get home and drive the car around somewhere with light traffic and see if it can maintain normal operating temp without the fan. If it can chances are the head gasket is ok. I will also mark the coolant level on the tank and compare when it cooled down. If there's no issue then it will go back to the dealer. I have a feeling they will try to sell me a new computer....
Either way I will report back.
04-21-2021 | 06:26 PM
#24
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Joined: 06-26-2017
Posts: 83
From: Los Angeles
Another thought snuck up on me. firemangeorge mentioned that an overheating TC can cause the fan to come on and not turn off. I wonder if all engine cooling related TC's cause the same thing, I had a silent one thrown for failed tstat. I cleared it but I wonder if it came back I just didn't notice as it does not come with a CEL. I will have to check that, too.
04-21-2021 | 11:36 PM
#27
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Joined: 06-26-2017
Posts: 83
From: Los Angeles
Reporting back on the issue:
I swapped a known good ACDelco thermostat in the car. Jacked up the passenger front of the car per Don's instructions and did a couple partial heat up - cool down cycles with some engine revving until no more air came out. Engine heated up to 217F, fan kicked in, cooled down the water under 180F in 30 seconds and the temp settled down at 181F with the fan running and not shutting off. Engine is not overheating and running beautifully. No DTC's and fan still doesn't shut off. Here's the kicker: After restarting the car with normal temp and fan not running I turn on the A/C, fan turns on as it should, I turn off the A/C and fan stays on. I think it's safe to say at this point that the problem is with the computer. Any objections?
I swapped a known good ACDelco thermostat in the car. Jacked up the passenger front of the car per Don's instructions and did a couple partial heat up - cool down cycles with some engine revving until no more air came out. Engine heated up to 217F, fan kicked in, cooled down the water under 180F in 30 seconds and the temp settled down at 181F with the fan running and not shutting off. Engine is not overheating and running beautifully. No DTC's and fan still doesn't shut off. Here's the kicker: After restarting the car with normal temp and fan not running I turn on the A/C, fan turns on as it should, I turn off the A/C and fan stays on. I think it's safe to say at this point that the problem is with the computer. Any objections?
04-22-2021 | 05:04 AM
#28
Platinum Member
Joined: 12-06-2009
Posts: 11,432
From: Alabama
Reporting back on the issue:
I swapped a known good ACDelco thermostat in the car. Jacked up the passenger front of the car per Don's instructions and did a couple partial heat up - cool down cycles with some engine revving until no more air came out. Engine heated up to 217F, fan kicked in, cooled down the water under 180F in 30 seconds and the temp settled down at 181F with the fan running and not shutting off. Engine is not overheating and running beautifully. No DTC's and fan still doesn't shut off. Here's the kicker: After restarting the car with normal temp and fan not running I turn on the A/C, fan turns on as it should, I turn off the A/C and fan stays on. I think it's safe to say at this point that the problem is with the computer. Any objections?
I swapped a known good ACDelco thermostat in the car. Jacked up the passenger front of the car per Don's instructions and did a couple partial heat up - cool down cycles with some engine revving until no more air came out. Engine heated up to 217F, fan kicked in, cooled down the water under 180F in 30 seconds and the temp settled down at 181F with the fan running and not shutting off. Engine is not overheating and running beautifully. No DTC's and fan still doesn't shut off. Here's the kicker: After restarting the car with normal temp and fan not running I turn on the A/C, fan turns on as it should, I turn off the A/C and fan stays on. I think it's safe to say at this point that the problem is with the computer. Any objections?
2. "cooled down the water". I hope you mean coolant here. There can be temp issues if using straight water instead of coolant.
04-22-2021 | 09:38 AM
#30
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Joined: 06-26-2017
Posts: 83
From: Los Angeles
1. I still think it's heating up too much at the beginning. The fan coming on at 217 is by design for what is considered to be the threshold of overheating.
2. "cooled down the water". I hope you mean coolant here. There can be temp issues if using straight water instead of coolant.
2. "cooled down the water". I hope you mean coolant here. There can be temp issues if using straight water instead of coolant.
2. Got caught being sloppy again.... Coolant obviously. I need to be super careful because you guy don't let anything slip. ;-)