JK-Rubi

My RIPP Supercharged '07 2DR gets extremely hot - much more than pre-supercharger.

ALs07

Had a 79 trans-am ( I know it's a JK forum) 400 ci, built the motor. The stock radiator which cooled the stock motor fine could not cool the built motor at highway speeds. Slow down,engine would cool down. Ended up installing a four core, no more cooling problems.

JEEPIN/J.S.A

Hey guys since ur already on the subject I'll chime in with a question related to this matter I took my jeep through a 3 1/2' pudding thick mud hole last weekend and completely plugged the radiator and fan and just about everything else under the hood after days of cleaning (i do mean days)i finally have it back to somewhat normal conditions but today i finally pulled the fan off to get the last of the mud out and stop my fan from vibrating (off balance due to mud) and i made an oops! i was tapping the fan motor to get the mud out of it and i hit it too hard and broke the magnets inside. SOOOOO since i needed the jeep asap and it was too late in the day to do anything about it i played electrician and pulled the thing apart (dont say it. trust me i already know!!!!!) but i got it apart and got it somewhat fixed and believe it or not got it put back together. but after i reassembled everything, I fired up the jeep, and the radiator was steaming hot after about ten minutes of ideling. it burned the hair off my arm when i leaned over the rad to see what was going on. anyway the fan kicked on and ran and my needle stay burried right where it always was (in the middle) I dont have an actual temp gauge just the dummy gauge but the needle never waivered, but the jeep seemed to be hotter than hell. I dont know if the fan is not working right or the thermostat went bad or a combination of both or if it was working fine and the steam was just residual water from me washing it but it steamed the whole time i was out there and stopped when i got it on the road and took it to work (5 min away). i have not started it back up lately to get it hot again as im still working but i was hoping someone could put my worries at ease since i have no way of know the actual temp of the engine.

Here are my questions...was this steam just from me hosing out the radiator? or should i be looking for something else? where is the thermostat on the 3.8. And did jeep use the same fan motor in the JK as they did in the TJ cause even though it is working (on a wing and a prayer more than likely) i still need to get a new motor for it. and since there isnt a part store around that seems to carry any parts for the JK (unless you need brakes) I dont really want to pay dealer prices. I need a cheap fix, fast!

P.S. sorry for the thread hijack. But i figured who better to ask than a bunch of guys who are already having radiater problems.

Rubiconjon

When I was working is a garage, we had a van that would overheat at high speed or under load. Fought with it for a day or so, then put it on the dyno. Found that the head gasket would lead under load but would close up under idle or slow driving conditions. Replced the head gaskets and no more overheating. Just food for thot.

TJ Willy

Thanks for the posts....

RIPP has mentioned that some 08s had a head bolt torque issue but supposedly mine was addressed during warranty work. I may just recheck them myself.
I'll post up after I check.

BTW, anyone have the torque specs for those?

Rob 12B1P

I dont know if its possible on a JK as I havent seen the thermostat, but on some older vehicles it was possible to install the thermostat backwards. It would give a similar result to the symptoms your having. The thermostat would open once the engine was warmed up but at higher RPM's the water pressure would push the stat closed.

TJ Willy

Watch your coolant level with regards to the steam. Hard to say exactly where it was coming from without inspecting it. My guess is it was just residual burn off. Your needle will move when the Jeep gets around 230-235 degrees. And with coolant mix, I don't think it would boil/steam below 240ish. The T-stat is right under the upper radiator hose where it connects to the front of the 3.8 - right below the intake/plenum. Can't speak to the fan as I don't remember/know what my TJ had in it. Probably not though. Your JK fan has two speeds. Make sure both speeds are engaging. The fast speed will kick on after the engine reaches operating temps.. kick on and then back off and then on etc. Definitely pop off your grill and hose hit the radiator with high pressure water to get the mud out.

cutter4292

Ive seen that more than once.

wytmike

Have you checked the lower radiator hose? If it is only over heating at higher rpm's, your lower hose may be collapsing. Once the rpm, drop it goes back to normal an flow returns.

Had it happen on my 66 corvette with a high flow pump. Full throttle and the temp would jump 25 degrees in seconds. New hose with spring inside and problem solved.

Mike

warpipe

Use AMSOIL MOTOR OIL AND COOLANT, THAT SHOULD DROP YOU 25 DEGREES