Overheating TJ

[stimpyson]

Hey all .. heres a question I hope some of you jeep gods can answer....

I bought my tj 5 months ago. its a 2000 sahara with 89K..... After my 3rd time 4X4ing my motor would get hot and overheat occasionaly at idle standing still... After driving a bit it was fine....

can dirt from 4x4ing get in my rad?? A simple rad flush perhaps?... my fan is turing so i dont think that is the problem...

I wnet to Mclean last night and it took me 2 hours to get home becuase i had to stop every 20 mins or so to let her cool down cause it woould hit the red.... (although I had tons of mud caked on my rad from a huge mud hole)........ After finally getting home i pressure washed the rad and now it seems ok... but will still overheat if standing idle for too long... ??

any ideas??

[RedApe]

Dirt in rad...possible, but I don't think that's the problem.

Thermostat --> I would look at replacing.

[TaTtOo]

How high is your jeep sitting (is it lifted)... You may just be splashing alot of mud up onto the front of your rad.  Out at Mclean Creek alot of the mud is clay and when it drys it becomes very hard and blocks the air coming in to cool your rad.  Also have you checked the level of fluid in your rad? Also I would check to make sure that your water pump is working correctly.

[stimpyson]

my jeep has a 3inch lift and 33's... and yes the mud was caked on hard!!! LOTSA CLAY....

Does a dirty rad (as in the fluid not being flushed) cause your system to sufffer??

[TaTtOo]

Well if the fluid is not clean in the rad it will certainly affect the performance of the heating/cooling system..... however if you have mud caked onto the front of the rad I would suspect that yours your problem.  Doing a rad flush and changing your thermastat would not hurt either.

[BlackYJ]

my jeep has a 3inch lift and 33's... and yes the mud was caked on hard!!! LOTSA CLAY....

Does a dirty rad (as in the fluid not being flushed) cause your system to sufffer??

Mud on the rad causes HUGE problems for cooling.  Think about it, the mud cakes acting like an impervious wall to allow the cooling air to flow through, thereby not cooling the fluid running through the rad.  Clean it out.  

When cleaning a rad DO NOT use high pressure, a garden hose or low pressure at the carwash will do.  High pressure can damage the fins.  Also make sure you wash it out from the back, ie engine bay, or else you will just drive the mud in further.  

I believe it is recommended to get a collant flush every 1-2 years depending on how the vehicle is used.  Offroaders should probably do it every year.

[wrenchead99]

I'm unfamiliar with tj's, but check your cooling fan.  If it's electric, make sure it works and if belt driven, make sure the fan clutch is ok.  At low speeds and idle, the cooling system relies on the fan to pull enough air through the rad to cool the coolant.  At higher speeds (above approx 35-30 mph)  the movement of the vehicle pushes enough air through the rad to ensure proper engine cooling.  In relation to your other problem, if the rad is caked with mud there ain't no air getting through there.  Hope this helps!!!

[Dragonmaster]

Also if you have AC you will have a condesor in front of your rad that looks exactly like a rad but it creates a nice space in bewteen the rad and ac condesor that really loves to collect mud that you can't see.  May need to remove the top shroud and peer down in the crack to see if you have mud, if so flush out with hose.

[swedge]

i've had the same overheating problems....i pulled out my thermo completely and made sure me rad was clean and i would still over heat...the gage would jump from 100-125 imm...then after 5 mins jump back imm. i was wondering if the water pump would be malfuntioning or if the fan clutch would be wearing. my fan spins fairly slowly while i'm over heated at idol.   any ideas :?

[dubbleJs]

I had problems for a long time overheating while on trails and only while on trails, crawling 4lo or 4hi. Replaced the Fan clutch last week and didnt over heat once this weekend 3 days of wheelin, the temp only jumped up a bit when revving on it hard while stuck in mud :? . lol.
One thing to be aware of, the auto value clutch i got sticks out about another 1/2" closer to my rad and while giving a guy a tug this weekend my motor mounts flexed enough for the clutch to punch a hole in my rad, careful!...last time I pull out some goof on fisher east in a stock 2wd truck. :evil:

[unionjack]

interesting as im running into the same thing wheeling, i replaced a pooched water pump, removed the thermostat and cleaned out the rad and still its running so hot that the overflow tank just bubbles over spilling coolant on the road?, im going to do a coolant system flush,refill and see what happens and if anyone has any other ideas pls let me know as this is killing some serious fun wheeling!!!!!!!
 :x

thx Darren

[unionjack]

interesting as im running into the same thing wheeling, i replaced a pooched water pump, removed the thermostat and cleaned out the rad and still its running so hot that the overflow tank just bubbles over spilling coolant on the road?, im going to do a coolant system flush,refill and see what happens and if anyone has any other ideas pls let me know as this is killing some serious fun wheeling!!!!!!!
 :x

thx Darren

[CJ-7]

From my exp. ( not nessecarly the correct practice haha :lol: ) the water pump will most often leak when it is "pooched". Otherwise the water pump is just an impeller and you would know from horrible noises and the belt breaking and squeeling if the impeller was damaged. If you are only overheating on the trails there is the most common reasons.

1  the rad fins are dirty and not able to cool the rad.......  Simply and carfully wash the exteior of the rad.     This is best done by soaking the rad with a hose then after waiting for a bit lightly pressure wash straight through. Be carefull not to bend fins!!!

2 If you have done a body lift to the jeep...... your clutch fan might not be in the correct position to cool the rad ....body higher and fan too low. This can be fixxed by adjusting the air shroud so that the air being sucked by your fan is all coming through your rad or lowering your Rad.

3. your clutch fan is not engaging soon enough or not spinning fast enough at rpm running on the trails. Replace !   Or if stuck on the trails and want a quick fix....... clean bearing on the fan and lock tite the squirt outa it ....lol...

4. My fix was and 16" fex-a-lite fan coversion ( some people like the ford taurus fan as well) attached to the rad and do away with the whole clutch fan assy.   Make sure to pick up a temp switch from a parts store that closes a about 5-10 deg. above your thermostat. and opens about  1-2 deg above therm opening. Wired with a relay will turn on the fan 5-10 deg after your therm opens and shut it off at operating temp(cause no one wants it too run all the time). I also rigged up a switch on the dash so it could be manually turned off for those big mud holes.


hope this is usefull

[unionjack]

thx , for the reply,the reason the water pump was replaced it blew!!!!, the rad is cleaner then when it was new and as for fan clutch there is not one , the body is lifted,and its running a 350ci sbc motor, im going to be doing a rad reverse flush and installing an electric fan from a pontiac bonnieville(perfect fit), and a better fan shroud, and give it a test run.
thanks for your input hopefully its a cure??

see ya on the trails

darren

[CJ-7]

No prob.   hope it helps