Prius 2013 engine bay gets real hot when a/c turned on.

tough to diagnose heat over the internet

 

i don't think i have ever heard of it before. i suspect that if it is hot out, and you are in the sun, the engine bay would get pretty warm.
but how to determine if it is abnormally warm? perhaps a differential infrared temp measurement with the a/c off and on?

 

IF.....the radiator fan is running whenever the A/C is actually pumping out cold air, then it's probably normal.

Unless a previous owner screwed with something like grill shutters........or your radiator has picked up a WalMart plastic bag or two.

 

Fans should be running. Remember: air conditioners don't make cold. They move heat.

Car air conditioners move heat from the cabin air to the air coming through the front grille. The fan is necessary to pull more air through, especially when you are at a standstill.

The air travels backwards from the condenser (where the cabin heat is dumped) then through the radiator, then into the engine compartment. From there it naturally breezes out. But while it is in there it will heat up everything it passes- the hood, the fenders, the headlamps, undercarriage etc.

 

Do you get an overheating CEL?
If not....well, engines get hot

 

I would make sure I had genuine Toyota-brand pink coolant in both the engine and inverter reservoirs.