This is me --- >

I'm stumped here... i need logical explanations... any help would be great.


Ok... so i did some mudding with the jeep.
(00 grand cherokee limited w/ electric fan from lincoln on it)

Radiator was packed with mud... so what right?
I clean out the fan and its all gravy.

No overheating in traffic or at idle.
But on the freeway, of course, its overheating a decent amount.

so i firgure its time to remove the radiator and pressure wash it perfectly.
so i do this, and i clean out the a/c radiator 'thing' at the same time.

anyways all goes as planned, everything is well, so i take her out on the freeway and up to speed where she always overheats... no overheating at all, so im happy ... job well done.

I hit up the KFC and I'm in line, just idleing, where it never overheats and it starts overheating! i goes from just under 210 to 230-235 and back down to 210... and then it does it again, and again... no throttle usage during this time period, no a/c on, no heat on.... im baffled.

(also, i currently have the fan running full time, and it supported the jeep at idle with tons of mud in the radiator, no problem...)

Now that i've cleaned out the radiatior its acting up... its makes no sense to me... the only thing i can think of is that there might be some air in the cooling system? or maybe my temp gauge is going south?

any help?

 

not sure how hard it is, but i would try replacing the thermostat with a lower temp t-stat, sounds like thats whats bad anyway as its intermittenly acting up under different conditions

 

ehh.

the thermostat is working good, unless it is closing when idle?

would it be possible for the system pressure force the thermostat to open while driving and not open while idle?

 

Maybe the thermostat got warped or something when it was over-heating and now it won't open all the way?

Just a thought.

chaikwa.

 

Not to mention, thermostats are usually pretty darned cheap and easy to replace.

 

i think it must have been an air bubble...

i just read some info over at wjjeeps.com and it told me i should have blead the cooling system. which i didn't and if you let it sit and cool down it will suck fluid from the ressy to fill up the air bubble. which it did, last night. today i refilled the ressy, and all today idle or hwy no overheating...

the warped thermostat sounds like a good idea too, but its cooling too good now for me to mess with it again...

here is a pic of what my radiator looked like after got it out of the jeep, yesterday. aka don't mud the DD!

 

**notice the mud chunks at the bottom

 

are you sure the engine is purged of air.
nissan 2.4s are notorious for trapping air and not circulating properly.

 

yea, its good.
it's been 2 days and no temp problems.

I could crack the bleeder just to be sure.