Is it possible you've got a blockage somewhere in the cooling system?

 

I have not found any support for that online as a cause of overheating, but if a clogged a/c system can cause excessive heat in the system, then I think this is probably it.

I just tried to fill it up with refrigerant and dye. now the pressure is high.

The hiss in the dash could be the refrigerant in the condenser I suppose. I am going to take a look at it.

I just put a new grom in and fiddled around back there, maybe I am pinching the line somehow.

 

I put on a new viscous fan clutch from Autozone, and it is cooler, but still heating to 215 in traffic.

 

I actually meant a blockage in the engine cooling system, not the AC system. I know someone (Charlie?) had that issue. Somehow a couple acorns had gotten in and got stuck in their thermostat.

 

I've recently put in a 180 degree thermostat, and refilled, and feeling the hoses they are all hot.

My money is on the condenser or a blockage in the A/C system. Maybe there is a bad valve or something. The A/C is not blowing very cold, and considering the heat coming off the condenser it should be an icebox.

 

I didn't realize your ac wasn't working well. I can see your logic then. Maybe it's got a restriction...making it hotter than normal...baking the incoming air...I'm with Alex I've never heard of such a thing. I guess anything possible.

If you don't have a IR thermometer get one. It will help when diagnosing and checking both ac and cooling system.

I'm in the middle of moving. While moving stuff back and forth I decided to do a little experiment. I ran the truck with no AC.Ambient was 106* . Truck ran at 188.6 the entire time. Stop. Go. Cruising. Didn't matter. I went up a long slow grade and it got up to 190.2 then came back to 188.6 once I got to the top. I switched on the AC and within a minute or less temps spiked to 204-207. That's amazing to me. I switched the AC off and bam.....it dropped back down to 188.6. That's a nearly 20 degree increas/decrease in operating temps almost instantly. I'm still amazed. Mine is teetering on the edge of acceptable temp range. I wonder if I pushed it hard could I get it to overheat...I'm sure I could.

 

It's nuts. Prior to this summer the car has always run at 200-204 with a 190 thermostat no matter if the heat or A/C was on.

I am going to take it in. I tried to get a look at the condenser, and that turned into a boondoggle.

I am going to get a IR though. useful for a lot of things.

 

I brought it into a mechanic I trust, and it turns out it is electrical in nature. The a/c system is overworking the compressor. Somewhere the signal is bad. We will see what they come up with. Ain't going to be cheap, but I am not capable of diagnosing it. I would just throw parts at it and cross my fingers.

 

I just got the 2005 GTO fan shroud. I gotta say like the look of it. It will need trimming, but with some weatherstripping around it I think I will get a really nice fit.

The fan has an 11" and 13" fans. I am going to hardwire them , and if they work get a variable temp controller.

 

Good to hear you found the issue. I hate electrical issues. Just indefinitely parked my 01 Mustang because of them.