Fan Clutch

I know, search and you will find. Tried that and couldn't find it again. I know I saw it somewhere in here but need to ask again. If the vehicle is "hot" and the ignition is off should the fan clutch be stiff to turn or should it spin freely when I turn it with my hand?

New everything, including the motor and the damn thing is still running hot.

There is no real way to test the viscous fan clutch. If you have an overheating problem and your fan clutch is over 5 years old, replace it. You can do a search, but I can tell you from years of reading this forum that some replace it every 5 years just to be on the safe side.

Thanks, it's actually new, but you know how that is. Sometimes good and sometimes bad.

Get a heat gun and an infrared thermometer and see if the coil releases at 180f


http://www.peachparts.com/shopforum/showthread.php?t=67800

CONTRARY TO WHAT SOME MISINFORMED INDIVIDUALS POST, THE FAN CLUTCH CAN BE TESTED, THE TEST PROCEDURE IS CONTAINED IN THE FSM.

See my post here on testing your fan clutch: http://naxja.org/forum/showthread.php?t=1023250&page=2

The test procedure in the FSM involves putting a blanket over the hood and idling at 2500 RPM for five minutes. Easier to use a heat gun.

ehall said:

The test procedure in the FSM involves putting a blanket over the hood and idling at 2500 RPM for five minutes. Easier to use a heat gun.

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Agree.

Thanks guys, I will try that.

Fan clutch is new and have replaced the catalytic converter and now replacing the coolant temp sensor. We'll see what happens.
Thanks

socal94xj said:

Fan clutch is new and have replaced the catalytic converter and now replacing the coolant temp sensor. We'll see what happens.
Thanks

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Keep us updated.

OK, so here is the very long run down of how I got here and what we replaced along the way.

The very first day my lift was completed in April of 2009, we went with the family and one of my daughters friends to Saddleback for some simple fire road fun. On the way the Jeep overheated severely while on the freeway at 65 mph.

Went to Jeep Care Center in Huntington Beach and replaced the water pump with a Hesco unit, new thermostat and thermostat housing from Hesco as well. The radiator was new and replaced by the previous owner. New fan and fan clutch.

Took it to work and it overheated on the freeway again.

Back to Jeep Care Center. They pulled the head and when they loosened the last bolt the head literally popped off the block since it was totally warped. They assume that either the head or the block were cracked and I was out of cash. So it sat in the parking lot of my work for almost 10 months.

Bought a reman ATK motor from Gearhead Engines. Installed the motor and started it up and it began to overheat, WTF? I was feeling a little cursed and started looking for Jeep shaped voodoo dolls.

Then I had had enough and began spending like an idiot, new fan clutch again, new thermostat again, new catalytic converter and it was still running a little warm at around 215-220* with some spikes into the 235-240 range when sitting at idle. BTW, the catalytic converter idea came from the tech at Hesco, I called and asked about the pump rotation and explained my situation and he offered many possibilities including the one I had never heard of, the Cat. He explained that if coolant got into the exhaust it could plug up the cat and cause too much back pressure and heat the motor. I checked the existing cat and could see some sort of thick black residual drip coming from the joint directly before the cat. So I replaced it for around $200, the Jeep was noticeably more responsive but the heat issue was still there. Then we replaced both temperature sensors and adjusted the timing and now it runs fine, steady between 210-220*.

Now that I have spent more money on the motor and parts than I paid for the stock Jeep, I better get some good use out of it. The way I see it is this, I could have bought another used Cherokee and swapped my lift and stuff over but then I might be in the same situation. At least now I know that most of the engine compartment is new and the motor has a 3 year warranty, kinda like a new car, but not quite of course.

Thanks to everyone for their help and suggestions and I hope to see some of you out on the trails soon.

Brian

Oh yeah,

The previous owner explained how he used the Jeep in Arizona to pull his boat (first mistake) and that it overheated but they replaced the radiator and it was ok (second mistake). Since I did not take it on an extended freeway test drive (third mistake) when I first came out to buy it I never knew about the overheating issue being caused by the cracked block and that it would vapor lock the first time I took it on the freeway for 20 minutes or more. This is what you can get when you buy a used car.

If you're in the market for a Cherokee, take it for a long test drive and include freeway speeds if you can as well as the usual tests, cylinder pressure, vacuum test etc.

Happy hunting.

I assume you replaced hoses along the way and the lower has a spring in it? When fluid is pushed through by the water pump it can create a vacuum on the lower inlet that will cause an old hose to collapse

Also are you running 50/50 or something fancy like water wetter

ehall said:

I assume you replaced hoses along the way and the lower has a spring in it? When fluid is pushed through by the water pump it can create a vacuum on the lower inlet that will cause an old hose to collapse

Also are you running 50/50 or something fancy like water wetter

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Most aftermarket radiator hoses for the XJ lower no longer come with the spring. Rumor control has it that the hose with the spring in it has been discontinued at the dealer, too.

Work around: for the lower hose use a "universal" ribbed-style hose, they have a spring built into them and there is no way one of those would collapse. If your current hose has a spring in it, and it is in good condition, re-use it.

Be sure its 'BURPED' good, and don't open the radiator cap! (Re-burp it if opened).

Check coolant reserve tank level is between add and full marks, cold engine (overnite) and hot engine (10 minutes+) should vary say 1/2 to 3/4 inch or so hot to cold. A good system should need less than a few Ounces added per year.

Good Luck,
Orange

Thanks,
I still have to "burp" it and I do plan on adding water wetter. As for the hoses they were replaced by the previous owner and look to be in good condition.

socal94xj said:

Thanks,
I still have to "burp" it and I do plan on adding water wetter. As for the hoses they were replaced by the previous owner and look to be in good condition.

Click to expand...

Just a minor flaw in the slaw.

When I was young, the heater and radiator hoses of that long bygone day would show indications of failing--bulges, mushiness(?), etc., but the hoses of today don't.

Check your lower hose. Without a spring a weak hose could collapse, especially with a high-flow pump, which you have.

Don't use water wetter. Use 1 gallon of green coolant, 1 gallon of distilled water ($2 at any grocer), and then top off with green coolant as needed.

orange said:

Be sure its 'BURPED' good, and don't open the radiator cap! (Re-burp it if opened).

Click to expand...

I've found that air bubbles in the system are often a (if not the) culprit in these situations. Air in the system can also make it appear is if the system is full when it's significantly low, which compounds the problem.

The air collects at the head then works its way to radiator IF there is not more air to replace it.
With air instead of coolant in head area, (The hottest area!) there is very little cooling and often the temp sensor reads wrong being in air.

I suspect many of the overheat problems are directly caused by lack of proper burping, and/or air leaks INTO the cooling system while cooling down from operating temperature.

A Properly operating coolant reserve tank and a fully 'sealed' system is the key to good cooling.