shing33

This auto has 240K miles, I had recently replaced radiator, pump, thermostat, most hoses, new coolant after a good flush.
Had stored the original viscous fan in an upright position all thru this. It has no electric fan. The Jeep runs around 195-210 F range even in the present hot and awful humid Indiana conditions. It looks clean and unhampered in front of the condensor which is in frt of the radiator.
Shortly after the AC is turned on, the temp starts to climb to 220 range or higher. If AC turned off, temp will also slowly get back in range.

Any thoughts would be much appreciated.

wingless

Welcome to the forum.

Which engine?

shing33

Thank you. Engine is 5.2 L, V8.

dave1123

People can say what they want about viscous drive fans, but I've found on older cars a mechanical direct drive fan cools much better than a viscous one does. Yes, it pulls more horsepower to turn it, but not so you would notice. It spins at crankshaft speed all the time, not lagging behind due to the viscous coupling. one of my friends with an old Chevy Impala drilled 2 holes in his coupling draining the fluid, then injected epoxy into the housing, locking it solid. You could do this with a defective one to try it. In my opinion, it should cool a lot better.

shing33

I really appreciate your answer, Dave1123. I notice no sticky leakage from the area of the fan that houses the silicone.
I just mentioned it in my post to indicate that I was careful to abide by the warnings to keep it vertical.
I owned this vehicle for 24 years and only just recently ran into this heat issue I can not account for..

What other three or four things come to mind that I should check do you think?

wingless

What was the coolant condition prior to the "good flush"? It is possible that internal deposits have accumulated reducing proper heat exchange.

When I had my engine apart, I scraped the internal coolant passages that were exposed by removal of the freeze plugs.

My radiator was replaced w/ a Valeo 732714, that is virtually identical to the OEM part.

Mine is fine temperature, all day long, in 90°F operating ambient temperature.

Does the vehicle have the OEM fan shroud and the OEM flexible air dams on each side of the radiator?

Is the fan spinning at the proper speed? If the viscous coupler is defective then it is possible to be spinning slower than normal, moving less air. I have an adjustable strobe light that permits me to quantify the RPM of rotating parts that is useful for this investigation.

Bugout4x4

Reminded me of a funny story about that... Back in the full service "fifty percenter" days when they would come out and poke holes in your tires and squirt oil on your shocks to get you on the rack, there was a trick one of my co-workers would do to sell fan clutches. He fabricated a small compact "impact tool" with a trigger to set it off from a valve spring. He would load it up in the vice to "set" it.

Then while checking the "belts and hoses" for customers he would put this on the end of the fan clutch where the thin cover was and set it off. The impact would smash the cover in against the shaft enough to lock up the clutch. The customers would come out and start their car and freak out because it sounded like an airplane. In the shop and new fan clutch with no argument every time.

It worked so well he ended up specializing in just fan clutches and didn't have time to do any of the other crooked stuff to cars.

Sorry to rat on you Sid... It was such an original concept I just had to share it.

shing33

Answering some of the questions:
-The coolant condition was very bad, After a chemical flush, I filled it and drove it for 1/2 hour, then reverse flushed it again with cold water until it was running clear.
-The radiator I purchased looked exactly the same as OEM, but not sure if as good as Valeo (They have a plant in Indiana)
-I used the original fan shroud and same rubber seal material on the sides. Since the shroud was slightly warped, there are some gaps in places which reduces the efficiency of the fan.
At the time, I deemed this to be a minor infraction.
-I cleaned both side of the AC condenser as I had the opportunity to do so, and used a return (bottom) hose that had a stiff coil on the outside to keep it from collapsing.
-During all this work last winter, I initially went with a 180 F thermostat, but got discouraged by lack of heat and switched back to the standard 195 F

I admit the fan speed may be the problem but don't have any way to measure it in different conditions. I'll check into buying something like that strobe light after the 4th(today).

Bugout4x4

Since it is a V8 this is what I would do if it were mine. Dave is right, I would get a fan clutch eliminator and an aftermarket racing "flexfan" and be done with it. The flex fan will help keep it from robbing much power yet pull more than enough air through as direct drive.

shing33

Well, it sounds like that is the majority opinion and I should go with it.
It is an anomaly then the original fan held up w/o problems so long.
Thank you all for using your past experience w my little problem