Okay, I am seeing 2 different sides to this.

I am the proud owner of a '91 Cherokee, straight 6, Auto, 4x4. I bought it last week for 800.00. Love Cherokee's. Had one back in the late 90's.

Anyway, I am having the exact problem the OP talked about: Around town, temp is good (WNL). But get it on the freeway......overheat. I have been throwing money at the problem, and frankly I am running out of money. I have replaced the t-stat, water pump, etc.

Been viewing other forums about this and the concensus is drill the stat at 6 and 12 w/ 1/8" or less to allow trapped air to pass. For those saying "no", please elaborate why not.

 

id take a second out on the house and dip into the savings for that ten bucks and take the day to come up with that 10 min drive to autozone and pick up a new one, who knows that little thing just might keep your engine from overheating some day which might cost more than 10 bucks to fix lol

 

Was that a yes or no on drilling the new t-stat? And if "no", what is your solution to any trapped air in this closed system?

 

go buy a new one, and last time i had air in mine i just ran it til the air worked its way out and kept adding water when the fluid level would drop, but thats cuz i was on the trail but it worked

 

What's the etc.? No need to put in a second t-stat if the 1st radiator, hoses, fan clutch, rad cap, coolant are still in/on. Is air flow thru the a/c condenser blocked? Full of mud? Fins bent?

 

LOL, sandaddik2, just noticed you are just over the hill from me.