ok i did a 81 swap to my 83 l.e about a mt. ago(rad. and oil cooler) took her on a 2k mile trip running the air with no heat prob.... well was running about 3/4 normal but not bad in 90-100 deg. with the a/c on...... But now ... i run about 1/2 normal with the a/c off and running down the hwy or on side streets in 90 deg. If i hit the a/c it runs about 99% hot in the normal(whay to dam hot for me), if i turn it off (a/c) it takes a long time for it to cool back down. I did add freion about 2 weeks ago but not till friday did it get really hot. the rad was free and clear of crap and i flushed the motor when i did the rad/ air oil cooler swap. What do you all think? also i did put on a new front dam and removed the little grill vent things(serzy are you haveing a heat prob.?) im thinking it might be a air flow prob but it does ok with out the air on. or a thermo.
I do have a black magic fan on her but i have never had a heat prob. like this. it does the same thing no matter where i have the fan turn on

 

Nope im not havin any overheatin problems my car runs at like a little less than 3/4 between the hash after C and the first skinny hash before H ... i dont even have anything directing air through the grill of my damn into the radiator yet... (Its on my list of Things To Do) so I highly doubt this is your problem... id offer some suggestions but the cooling system I know little about...

But dont forget to check the simple stuff... dont do what POS Racing did... (no offense POS Racing, we've all done the same thing at some point, I know I have )

 

Is your fan clutch or electric fan kicking on when the air is on?

Good luck,

 

No offense taken!