Suspect water pump

Dreadnaught

I know lol.

What do you work on at your shop? A little bit of everything?

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Ford Diesel and Heavy Line Technician at your service.

fryzia23

I started turning wrenches 5 years ago at one manufacturer(lexus) so I can only base my experience from that. I came from oil changes, diagnosis to engine overhauls. Generic diagnosis might be similar but part design, type of noises, common issues, procedures, etc could be way different so sometimes trying to fix one car based on another doesn't always work. Fortunately switched to Porsche two months ago so no longer with boring lexus

Anyhow lets try to help OP to fix his car. Since the car is only overheating on idle with ac on I cant really think of anything except insufficient air flow through the radiator. If there was an air pocket it would still overheat with AC off, the heat in the cabin would fall off from hot to warm during idle. Strange..

Z_ealot

It has been very strange for me as well, I've been going through the most common points of failure in the system starting with the thermostat and working through the most common procedures to address the issue. The only thing that i havent changed in the system is the water pump which is partly what leads me to believe it may be the culprit by process of elimination. I appreciate the help in this situation and look forward to any more input anyone has on the issue

Dreadnaught

Yeah, it sounds like a fan issue while the OP is at an idle, even though the OP has said the fans are working.

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Ford Diesel and Heavy Line Technician at your service.

Z_ealot

its not just the fans are working though, I can feel with my hand a pretty good amount of air being blown through the engine compartment when they are on and also feel a good bit of air being sucked through the front air dam when I put my hand in front of it. also, as someone suggested I went and rented a radiator pressure tester. pumped it up to 16 psi and it holds pressure steady with no indication of any leaks, let it sit there for a good 5 minutes too with no drop in psi at all.