I never overheat but in stop and go traffic my temp gauge creeps up and my AC effectiveness drops. Get back up to freeway speeds and everything goes back to normal. Turn off the AC and temp gauge drops to normal. I only notice it in the afternoons/evenings when it is 90+. I took it to the car wash and sprayed out the radiator and condenser thinking it was dirty but that didn't help.
Next it seemed like the fan clutch was not disengaging. I replaced that and the water pump both with AC Delco parts, flushed the system and refilled with Dex. I replaced the thermostat, temp sensor and radiator cap last fall, also with AC Delco parts.
I still thought it was an air flow problem so I had a shop look at it yesterday. They said the fan was coming on as directed by the computer. They could not get the temp to come up over 206 while sitting in the shop with the AC on (dash gauge reading just past 210). He said he could not force the fan to full speed but it was running at the correct RPM as called for by the computer while idling with the AC on (700RPM). They suggested the radiator is plugged. I asked them to use an infrared gun which showed a 20 degree difference between the top and bottom. I am sure it is original but I would think the heating up would be more constant if it was plugged. I can get a new AC Delco for $140, replacement does not look too difficult. They wanted $900 to do that, including evacuation/recharge of the AC from pulling the condenser. Doesn't look like I need to do that.
I am still thinking an air flow problem though. I did install a Derale 8000 transmission cooler last fall in front of the condenser on the driver's side but I would hope that is not restricting that much air flow.
I'm great at replacing, terrible at diagnosing.
Thoughts?
2005 with 112K miles.
Next it seemed like the fan clutch was not disengaging. I replaced that and the water pump both with AC Delco parts, flushed the system and refilled with Dex. I replaced the thermostat, temp sensor and radiator cap last fall, also with AC Delco parts.
I still thought it was an air flow problem so I had a shop look at it yesterday. They said the fan was coming on as directed by the computer. They could not get the temp to come up over 206 while sitting in the shop with the AC on (dash gauge reading just past 210). He said he could not force the fan to full speed but it was running at the correct RPM as called for by the computer while idling with the AC on (700RPM). They suggested the radiator is plugged. I asked them to use an infrared gun which showed a 20 degree difference between the top and bottom. I am sure it is original but I would think the heating up would be more constant if it was plugged. I can get a new AC Delco for $140, replacement does not look too difficult. They wanted $900 to do that, including evacuation/recharge of the AC from pulling the condenser. Doesn't look like I need to do that.
I am still thinking an air flow problem though. I did install a Derale 8000 transmission cooler last fall in front of the condenser on the driver's side but I would hope that is not restricting that much air flow.
I'm great at replacing, terrible at diagnosing.
Thoughts?
2005 with 112K miles.