Hello there! I just brought my 1990 Cherokee Pioneer back to life, more or less, and am having a few problems. 1) The electric fan is not coming on. I tracked back as far as wiring the fan to the battery and it works, just not coming on...my manual seems to have migrated, so if anyone could point me in the general direction of the relay, I would be greatfull.

2) My next question is involving the rebreathing crap (what looks like a PCV tube out of the valve cover and runs into the air box). The tubes are cracked, the plug into the block is leaking...do I need this stuff? I live in a non DEQ area, so can I just plug a breather cap in and go?

Thanks
--Todd--

 

Todd the Renix needs the vacuum of the intake to scavenge the fumes from the valvecover. Which plug in the block is leaking and what is it leaking? Coolant or oil could be coming from various plugs.
The relay that you are refering to for the fan is on the passenger side fenderwell IIRC.

Please post a short hello in the introduction section and we like to see pictures of your Jeep so those would be a plus.

 

For the fan, it is either the relay or the sensor. Does it turn on when you turn on A/C or Defrost?

 

one more thing to look at is the coolent switch in the rad. it just above the trany coolent inlit. easy to get to.

and that pvc thing... the hose in frunt you can get rid of it as long as you plug the air box with somthing my. i took mine off my 89.

 

It don't turn on at all, only if I direct wire it to the battery. That is what makes me think it is probably the relay. (But I figured there are people here with WAY more knowledge than me.)
I will try to dig out the digital camera and get some photos of the Beast uploaded this weekend. Thank you all for helping out!
--Todd--

 

It is the L shaped hose that plugs into the block, just in front of the oil filler. In my other car this is a PCV valve...but the guys at Nappa Auto told me the 4.0 has no PCV on it, that this was just routing air from the airbox to the valve cover. It is cracked badly around the integrated gromet and likes to randomly sputter oil all over the block. When it overheated the other day, I lost at least a half quart (maybe a bit more) out of this damn connector.
--Todd--

 

Your engine may not even be running warm enough to trigger the fan. That's the case with mine. As far as I know, the renix's have some EPIC cooling systems. Even in some hard summer driving the fan has RARELY been triggered. If you're worried about it, you can install a manual switch to bypass the relay and manually engage it from inside.

 

That may be the case, but 6 or 7 years ago (when she was a daily driver) The fan came on anytime the temp guage went over 200. Now...the engine overheated pretty bad and the fan didn't come on. I am going to trouble shoot the relays and wiring this weekend, if that fails I may run the bypass switch like you suggest.

Also going to flush the coolant and check the thermostat. next weekend it will be a PCV swap out and probably a valve cover gasket.

 

That fan only kicks on when your A/C system is charged and turned on. I drove mine for 2 years and it never came on till I finally filled the A/C system then after 2 years of being empty WIIIIIIIRRRRRRRRRRRRR!!!!!!!!! try that.

 

So with that information, do you think I may just have a bad thermostat?

 

ok...new information. Yesterday I took the air intake line to the valve cover off, it was clogged up and nasty. Decided to replace the (original) valve cover gasket while I was there. What lay inside suprised me on many levels. I took over a pound of crusty oil sludge out of the valve cover, the baffles, and off the lifters. It was epic and gross. I have no idea how the poor thing was running, I can't imagine that the oil journals are in any better shape.

The fan works now (after a new relay) and does in fact only trigger when the blower for the AC or defroster is engaged. (thank you for the tips on that!) I started the flushing of the radiator and cooling system. Swapped out the Serpentine belt and grabbed a new thermostat. (Whish I will be putting in AFTER I get done doing the flush and clean. Then I have to get a breather plug and probably ought to change the oil again soon...I am guessing I knocked alot of crud out and back into the system that will be finding its way to the filter soonish.
--Todd--

 

On a high mileage, gummed-up engine, some people add a quart of trans fluid to the oil and drive about 10-20 miles before they change the oil and filter. The high detergent properties of the trans fluid helps cut the built-up sludge in the engine.

 

If your coolant temp sensor is not working for the computer side of thins your fan will never come on, if you have someone with a scanner see if they will scan it and see if the computer is reading the same as the gauge. (And as far as a motor flush with that many miles DONT you will cause some noises you dont want).