jretzky

It's summer again and the Jeep is over-heating again.
No the e-fan is not working and I replace the t-stat, relay, diode, temp. e-fan switch in the radiator and new 50/50 anti-freeze. Only 4 mo. ago I replaced the e-fan.
Is there a fuse under the dash or under the hood for the e-fan?
The e-fan works when the defrost and or air conditioning is on.
The book says to run the jeep with the lid off the bottle (no cap on radiator-closed (radiator) system). When the t-stat opens the coolant will be sucked out of the bottle, but it doesn't happen?
There is nothing wrong with the oil and the engine runs fine, besides over heating. When I rev the engine, the bottle doesn't blast out coolant.
After driving the Jeep with the cap on bottle, it looses coolant from the cap (bottle is good). The cap has an "O" ring that is good.
I have searched this and found that most people say it's either the clutch fan on the motor or there is an air bubble in the system that won't release???
I would appreciate your help!~John

VTJeep

Bypass so fan turns on with acc?

Slick761

First of all if its working with ac then the system is working fine. Unplug the temp sensor at the radiator and jump the wires together on the connector that plugs in to the sensor. That should turn it on and that should be the only reason it won't turn on now. Look at the wiring diagram. As for burping the system did you drill a small hole in the t-stat (or it should already have one) it needs to be up when u install the t stat. I find that if u run the engine until its hot then crack the lid open a couple times to bleed air then leave the lid on and rev the engine to like 3500 a few times it will het the air out. Two reasons the fan isn't coming on and its overheating are 1- big air bubbling behind thermostat 2- thermostat installed backwards. Either way it sounds like the thermostat isn't opening so the temp of the coolant on the radiator isn't high enough to trip the fan.

jretzky

Slick761, the temp. switch is fine in the radiator (jumped the wires).
Ran the Jeep with the e-fan running on defrost, still over-heated.
T-stat is in correct way, but no hole in it and will try that tonight.
Had 180 in there, but put in a 195 to really get the coolant hot to kick on the temp. switch and relay.
Will try your method of bleeding the air out, but the top and bottom radiator hoses are hot. I shut down the engine and let it cool and squeezed the top radiator hose and some air came out.
Thanks!~how big of hole do your drill 1/8?
John

Slick761

Supposed to be smaller but I drilled 1/8 and it worked great. Most people will tell you to pull the cts in the back of the block and park downhill then fill the system and screw it back in when coolant starts coming out but that didn't work very well for me. When I revved it a few times it forced the air through. It got up to about 215 and would drop a little as I revved it then finally it dropped way down. Just make sure u don't fill the tank all the way and as you add coolant to fill the system do Ot slowly and keep it below the return tube in the tank. The fan didn't turn on when u jumped the wires?

DFlintstone

And maybe stick a new cap on it. Cruiser swears on the OEM, IIRC, but cheap enough to rule that one out.

Slick761

I swear at the oem!! Hahaha

DFlintstone

Yea! Wouldn't know myself. Got enough of them laying around since I end up with one with each replacement bottle. There is an extra in the Jeep somewhere. Idk if the mice are using it for a card table or something.

Slick761

Hahahaha

jretzky

The Jeep is not over-heating any more. Drilling the hole really works.
Do the t-stat from the factory have holes in them?
The temp.e-fan switch is good.
Still the e-fan doesn't come on just idling.
It will come on with defrost (and ac) and then turn on and off at times.
I know that works with the ac line pressure and the cycling of the ac compressor.
Bought an Craftsman electric testor.
What or how do I check the wiring for the e-fan???
Does any one know if there is a fuse under the hood or dash???
Thanks!~Jretzky 89 Laredo 4.0 L

DFlintstone

I'm pretty sure the temp deal on the radiator is a switch that closes to activate the relay at something like 217*. I think you can pull the connector and jump to see if it comes on.

Slick761

The e fan should just turn on and off when the temp gets high. Sounds like its working.

jretzky

Nothing else I can do. The Jeep seems to run cool with the hole in the t-stat.
I wonder if my temp. gage in the car is working right any how.
I see wiring harnesses on line for $40., but I took my harness a part and where ever I found electrical tape I unwrapped it to see if the connections were good.
Last year the engine temp. would hit about 200 idling and the e-fan would come on, but not this year.

It's frustrating because I put an hot wire and a switch on my e-fan for my 1992 Ford Escort and I burnt out the ignition switch that cost almost $400. to fix at the Ford dealer. Still haven't figured out that one either.

John

Slick761

Fan shouldn't come on till about 216

jretzky

One day my horses decided to jump the cattle guard and I drove the Jeep, so I could catch them. I left the Jeep idling in neutral with the e-break on and it went over 220 with my temp. gage. Well now I don't know if that would happen, since I drilled the hole in the t-stat.
I went to a trade school in Chicago for auto mechanics, but back then I didn't have e-fans and then I only drove 8 cylinders.
Will leave well enough alone. Haven't taken any long trips yet.
Plan on painting the 89 Cherokee this summer and putting some better tires on.
The hood on mine is cooked...makes me wonder what happened. It has a new water pump and several other things. I got the car for free and gave a lady a ride to Billings bus station for it. It was over heating then the plastic vacuum valve for the heater core broke and the tube to cool the exhaust manifold was hitting the e-fan and it busted it up. The lady was driving from Montana to Florida going 65 mph because she said it wouldn't over heat then. She took the bus and I got the car and 3 mo. later I got the title. She left her cell phone and check book in my car (if it wasn't for that) I don't think I ever would of got the title. Well it's been nice...I have a project car and good one for hunting and driving up the 300 foot hill to my house. In the winter I plow the hill with a 1967 Dodge D200 (but now a 4x4) that I completely restores (and rebuilt) and have had for 25 years now.
John
Thanks!!! Once a gear head- always one!~never hurts to ask questions.