YJ gettin hot

[allabs5150]

87 YJ with 89 4.2 engine, brand new radiator, hoses and 190 thermostat, as well as new temp gauge along with temp gauge sending unit

when running on the highway temp seems to fluctuate between 195-200, but as soon as I go off road and ride around slowley in first and second gear it almost immediatly heats up not overheating but after about 15 minutes of slow woods riding the temp gauge starts pushing past 230-240 then as soon as i get back on the pavement at highway speeds the temp drops right back to the 200 range. I was thinking about going to a 160 or 180 thermostat but havent made the switch yet.....anyone of any idea what else could possibly be causing this issue????

 

[Sine Deviance]

Mechanical cooling fan with a bad clutch?

 

[allabs5150]

yes it does have the stock fan set up......how would i be able to tell if the fan clutch is bad?

 

[elevatorman]

With a hot engine you can hang a rag in the fan,if it stops or even slows down the fan then your fan clutch is junk.
SAFETY NOTE__ LONG RAG AN NO FINGERS IN THE WAY.

 

[allabs5150]

think you guys are right about the fan clutch being bad......I didnt try your looooong rag technique yet elevatorman, but i did a little research on fan clutches and what their job is and well the issues i am having seem to point directly to the fan clutch.