Overheating Problems

[mattawajeep]

Trying to figure out why my TJ is overheating w/ the AC on, and I have a few questions.

Temp is normally fine both at idle/crawling and highway speeds. I can also run the AC at both of those speeds without overheating so long as it is less than 80 degrees out.

However, once the external temp climbs above 80, and I turn on the AC, the engine temp starts to heat above 210 and the transmission temp (3 speed auto) starts rising from it's normal ~190 to match the radiator.

I've replaced both the radiator cap, and the thermostat (making sure it was the correct 195 degree model) and am wondering if I might be having fan clutch problems. Does the fan clutch only lock on/of or is the speed incremental?

If it's not a weak fan clutch, I'm wondering if my radiator has a problem, or simply can't take all the additional heat generated by 35" tires and 3.73 gears.

[White trash]

Yea 35's and 3.73's aren't the hit setup for hot weather.

Will it overheat at idle or just above it or just while driving?

[mattawajeep]

Yea 35's and 3.73's aren't the hit setup for hot weather.

Will it overheat at idle or just above it or just while driving?

Overheats at idle and while driving.

[White trash]

Easy check is to try spinning the fan clutch while the rig is HOT. If it spins easy there is your issue if it is stiff survey says you need a radiator. I'd highly recommend radiatorbarn.com

[mattawajeep]

Easy check is to try spinning the fan clutch while the rig is HOT. If it spins easy there is your issue if it is stiff survey says you need a radiator. I'd highly recommend radiatorbarn.com

Guess I'll give that a try this afternoon. Was hoping it wasn't either one of those. Looks like I'm probably gonna have to spend some money.

Oh well, looks like an OE style radiator is pretty cheap, and a fan clutch should be cheaper.

[Lurch]

I hate to point out the obvious but make sure your radiator and condenser aren't plugged with mud, grass, or the neighbors cat

[mattawajeep]

I hate to point out the obvious but make sure your radiator and condenser aren't plugged with mud, grass, or the neighbors cat

Heh, I almost got my moms cat yesterday, but sadly that's not the problem. Radiator & condesor are surprisingly clean for as old as it is.

[SPR]

I had similar problem in the Toyota once. I purchased an installed a new radiator and fixed the problem. Closer inspection of the old radiator showed it about 1/3 plugged with Tampico clay.... Yes, I was a dumbass for replacing the radiator

[mattawajeep]

I had similar problem in the Toyota once. I purchased an installed a new radiator and fixed the problem. Closer inspection of the old radiator showed it about 1/3 plugged with Tampico clay.... Yes, I was a dumbass for replacing the radiator

Heh, don't feel too bad, I've done the same thing on an old John Deere at work. Though we discovered a pretty bad leak after the dirt/grass/tree/applesauce was cleaned out, so the radiator was actually necessary.


Checked out the fan clutch, and I'm pretty sure it's the problem. Got the engine & transmission nice and hot and the fan has almost no resistance at all. Now I'm left wondering what to replace it with - seems like everybody makes a fan clutch - and at widely varying prices.....

$26

$55

$100

Seems like there might be differences on when they engage, and how fast they spin when they do - but It's hard to tell. Gonna give the stealership a call and see what their prices are.

Anyone have a suggestion on a trusted brand? I don't mind paying more, but I'd like to know it's going to work well/better first.

ETA: Dealership quoted me $249, so I think I want something aftermarket. But now that I know jeep brand ones are worth so much I'm gonna get a gold chain and wear the old one around my neck....

[Power Wagon]

Basically, just look for a common brand. Normally, you can get hayden and flex-a-lite for reasonable prices. Make sure you get a thermal clutch. It will provide good cooling at low engine speed when you need it.

mind posting your year, etc, and I can find you a decent deal on one.

[Wrench]

For that price, you could easily convert it to electric. Orielly's sells a good wiring kit for this. It has a thermal probe that you stick in the radiator fins, and the control box has an air conditioning input to run the fan full-time when the AC is on, and it also has an adjuster so you can control what temp the fan kicks on. I installed one on my Chevy.

[White trash]

Electric is good too. The adjustable thermostats don't live a ling life though. If you search a parts catalog you can find a stock temp switch to turn it on and off at the appropriate temps or you can cheat and order one from summitracing.com in the temp you want.

[iaccocca]

If you are thinking electric... Flex-a-lite (I think and could check) has a bolt in TJ setup that looks pretty sweet. If you are comfortable with electrical, I think the trick setup is a Ford Taurus fan, but it has a huge draw on startup, so it isn't a straight forward install, but there are lots of write-ups on it.