I wish Raz would pop in sometimes, with an opinion!
I believe we have covered ALMOST everything!
Mr. Radiator may have mineral build-up inside......Fix? professionally taken apart, vatted, reassembled....$35 last time Mr. Jeep was done.... surely no more than $60 now, for you??? a auto store "flush" is usually a waste of time and $$$..or.....a New Radiator would eliminate this problem also, and it would have "Zero Miles"
Your radiator is 14 years old? 2 high priced cleanings, same old radiator vs this below
Water Pump works--seizes--or starts leaking, never seen a impeller come off or freewheel, myself.....'bout all that one will do....they don't usually stop spinning or get worn down, inside the engine
Heads are a possibility...a pressure test or a chemical test (I'm not familiar with) should INCLUDE or RULE this out as a factor......If this is done on a "Guess", this will be a sorta/ maybe not cheap thing to do..............what if It solves nothing?
It has been really hot here, my temp is up some too. I have 2 gauges on mine...Factory Electric, on the rear of my head, and a mechanical one in MID ENGINE BLOCK..........Mid Block stays cooler normally because it's lower maybe getting the FRESHLY COOLED Radiator water 1st...or heat rises and the Electric is up there!
Usually the Mid Block will change the most, as long as it stays within it's normal borders, I'm happy....If I get concerned, I see what the other is doing!
In the evenings or really late, when ambient air temp is Normal?, All is perfectly down where I call normal
Hows yours act at night?
I have seen the fellers at Advance Auto, pressure testing cooling systems, I reckon for Free, as other things they do are.
I'm sorta stuck! I think I have prepared you the best I can.
I can only tell you what I know or perceive.....you are at the mercy of yourself and choices you make. You must weigh out factors like $$$, gonna keep this puppy? Are you walking now? Etc. Etc....you have ruled out some factors! So you are doin' good!
Below is my Primitive, but also Awesome, User Friendly, Working Instrumentation in "Mr. JeeP"........Note: Mechanical (most trust-able) Temp and Oil Pressure Gauges are closest to the Pilot's Seat, for EZ viewing.....Label Machine tape on Speedometer shows next oil change
Tuesday, July 26th, 2011 AT 4:06 AM