Every PSI raises the boiling point of the 50/50 coolant by 7 degrees. instead of running a 13 lb, youre running a 16lb which is ~21 degrees warmer

 

So i am just gonna run the 13 lb then. Better check after my flush that i am 50/50!!!

 

Actually DJB i don't think our fan is the flex-lite style. AFAIK the clutch is fully engaged when the engine is hot, meaning the fan is pulling at engine speed no matter what speed you're moving.

 

No, it's not a flex fan or anything like a flex type fan. The principle of operation is way smarter than any flex fan. The clutch is never 100% locked with the pulley speed. It freewheels less when higher air temp from the rad is sensed (about 170F air temp) and freewheels more at lower air temps. The principle behind a clutch fan is to freewheel as much as possible, thus less drag on the motor. As air temp coming off the rad rises, usually caused by the vehicle moving slower, the clutch freewheels less, turning the fan more, and pulling more air thru the rad.

Clutch fans have really gotten a bad wrap but the principle behind them is really good.....when functioning correctly and not needed, virtually no drag on the motor, when needed, they move some major air. While freewheeling, virtually no load on the motor but still pulling some air thru the rad and moving it around the engine bay.

The clutch mechanism is mechanical, wears out gradually and should be considered a routine maintenance replacement item. No where in the FSM is the so called "spin test" or "stick in a broom handle test" discussed. Folks, it's a low cost replacement item......just put a new one in every 4-5 years and if u recently acquired your XJ and there's not a receipt in the glove box for a recently bought/replaced fan clutch............................................ ......put a new one in...............do some maintenance.

 

 

Sorry to bring this back up again, but i am getting high temps again. I flushed it, new tstat, new rad cap. Troth said new pump maybe. Think that will do it. Btw-rig has 170,000 miles sooo...... Thx again for the help!!!

 

Have u replaced the fan clutch and radiator? (Sorry, don't want to go back and re-read). Water pump, radiator, t-stat, fan clutch and coolant are the major cooling system components.

 

i was leaking a lot of coolant out and running extremely hot just recently, and i just went to o'reilleys and bought a waterpump and gasket...turns out it just needed a gasket, but hey, for $28 bucks, just go ahead and replace that waterpump and gasket...mine runs alot better because of it

 

Fan "seems" to run ok.
Heres what i noticed today: it seems that it only overheats at higher speeds. Is it possible that a hose could be collapsing restricting the flow of water into the radiator? The hose going from tstat to the radiator is very rubbery/old. Could it collapse when the system is under greater pressure at higher speeds???

 

Not leaking now. It was the hose that connects the tstat housing to the radiator. It is getting soft/old. Where it clamps to tstat housing, the clamp had cut through the hose. O.o

 

Usually, overheating at speed is a coolant flow problem or the radiators inability to loose heat or both.

 

Is there anyway to test radiator or water pump??? A buddy told me to loosen tensioner and spin water pump, might tell something?!?!?

 

You could check for drag in the water pump bearings that way. Grabbing the pulley and moving it around (like how you check wheel bearings and ball joints) would tell you if you have excessive play in the bearings too.

 

Yeah thats what he was sayin. If I don't go over like 55 or so, it doesn't heat up.

We will check this friday see whats up. Thx guys!!

 

The bearings have nothing to do with the flow of water, the impeller is what moves the water. Only way to check the impeller is to remove the water pump......if u remove the old one, might as well replace it with a new one (+/-$40).

Only way to inspect/thoroughly clean the inside of the radiator core tubes is to remove the rad, have a rad shop remove the tanks and "rod out" the core. For +/-$120 u can install a new radiator.....