Could my AC be overheating my truck?

[davepl]

Short story: on a hot day (>80), at idle, with the AC on max, my stock 402 truck cannot hold its temp at the thermostat point of 180. It creeps up to at least 200+ and really seems like it'd go forever if I didn't intervene. That takes half an hour though, it's not fast. So traffic jams and parades are a problem. But I bet from the factory you could do it.

I put a SPAL 12" pusher fan in between the condenser and radiator yesterday and it comes on at 195 and helps somewhat. It seems to help the engine stay right at 200 or so, but if I had more time maybe it'd still creep up, I don't know. It was a significant improvement but not a "fix".

What stymies me is that this truck is totally stock and totally restored. New rad, new GM clutch fan, proper shroud, etc. There are two things it's fighting:

- Even fully warmed up there's more exhaust coming out of the driver's side, so the crossover is still bouncing closed, forcing hot exhaust through the intake manifold. I could wire it open for summer, but they didn't have to stock.

- With the AC off it'll idle at 175F all day.

So the AC thing made me wonder "Well how hot is the air coming off the condenser" and the question is "too hot to touch". You can't touch the condenser, it's literally that hot.

So that's the one thing that's different - R134A and a parallel flow condenser. And it DOES rock the cold air in the cab very nicely and freezing cold. So I'm wondering if the AC system is maybe moving more heat than it would have stock, due to the parallel flow condenser, and that's causing it to have trouble cooling the engine at idle?

Thoughts?