my 92 yj is running around 230 235 while driving at high way speed. then when in town or traffic temp cools down to 200 210. have changed coolent ,temp gauge,thermastat, flushed system. new hoses. i have installed a flex light black magic electric fan. seems hot but ??????? any body have any imput on this matter.

bad guage?

This may not be related to what you have but I just did a job like this at the shop. It was a 94 cherokee with a 4.0 and it would get hot whenever he was hard on it. I ended up finding out that it had a cracked head and leaked only when he dogged it.

Is the fan pushing or pulling? If it's pushing, you are fighting it at highway speeds and stalling the airflow through the radiator. It may also be a capacity thing. If the electric fan doesn't move quite as much air as the mechanical one, you would notice it on the highway first. Does it have a speed control?

its a puller and no speed controll. i've had the fan for over a year. the heating problem started about four five months ago.

once on the trail she runs cool. its getting there that worries me. is 235 just to hot to be running at for 4 hours. thats about avrage drive time to most trails close to me

Maybe pull the radiator and give it a good hosing down? Could be mud/salt/crap from the winter clogging up the fins.

My wife's cavalier had a similar problem, it was a bad head gasket.

You should be cooler at highway speed than trail riding because the air is forced through the radiator.

i know. thats why we are all stumped. radiator is clean. just pulled engine out and did a good replace in cleaning. head gaskets good.

Yank the thermostat out and run it up the highway see what happens. Could be thermostats not opening enough to allow proper flow to cool at higher RMPs.

If it's the head gasket, your exhaust will smell like coolant or your oil will be milky looking.

I've seen bad brand new thermostats.

yeah third thermostat. checked flow seems to be good with thermo. im going to burp system again. then will probly try run with out thermo.

If you're running the original radiator then I would say that's your problem. Even though you flushed it out it's probably clogged to the point that when you run on the highway it can't keep up with what the water pump wants to push through it. You've replaced everything else. I think you should take the last step and put in a new rad.

thats kinda where i've been leaning to. should i go two core stock, three core or aluminum.

I have a 90 yj with the 258 too. It runs very cool on the trails and warmer on the hiway. I have a 2 speed electric fan and to keep it below 210 i have to run it on hi, low wont do it. On the trails its no where near 200 even. I have a new radiator and just put the engine back together so i know its clean. I have a 165 thermo too. If i take the thermo out it runs cool all the time, those thermos cut the coolant flow down way too much. Just my 2 cents. Try no thermo, i bet that will help.

my 89 had the same problem, ended up getting a new radiator, several people suggested checking water pump (they said the fins can wear down and not be able to push enought coolant through the radiator) also, the bottom hose should have some type of support (coil) or it can close up at higher speeds. again, this is what i was told to check.

Having the same problem I've replaced fan clutch thermostat put a hesco high flow pump in new rad cap flushed the system twice did a block test I'm doing the rad this week let us know how ya make out

well i flushed the system. again. if i ckeep my rpm around 2000 it seems to stay around 220 . so im going to try and get up to the mountains this week end( or at least some where). and well see how she runs.

How high are your RPMs at 55? If they are higher than 1500-1700, I am assuming you are running sans fifth gear.