ok y 88 TII heats up to like 195 or so at highway speeds like 70 or 75, but at idle or low speeds it runs 180, this is being mesured using an aftermarket gauge. what could cause this? Im thinking it not having the aluminum belly pan or tray whatever u call it that goes under the engine might be the problem,. what do yall think??

other cooling stuff is fiero gt electric fan, new thermostat and waterpump...

 

I've heard that if you don't have the plastic undertray the car will overheat at highway speeds. Might be something else also.

 

Probably the tray

 

sorry to break in, but out of curiosity do you know why the removal of the undertray increases heat rather than decreasing it? Just curious..

 

Air flows under the car instead of through the rad, hence less cooling at highway speeds.

 

Hmm, that makes sense.
Thanks!