So, my buddy (jeepsurfer1, good friend) has his 96 xj with a HO 4.0, he gets tons of overheating issues even after doing a head gasket. My 4.0 renix had overheating issues untill i did my head gasket back in feburary ish, and i can barely keep it at 210 degrees, even after a hard highway acceleration then sitting in traffic for like 10 mins, it will tick 210 then go back down to like 180 tops. I dont run any extra cooling, hell the elec fan doesnt hardly kick on ever now. Just curious to any ideas why it runs so damn well now, and my friends much more recent (and better kept after, my previous owner didnt take good care) motor still overheats so hard

 

Comparing 2 different vehicles is like comparing apples and oranges. If u r running 180, sounds like something is wrong with yours as well. Who's done what to their cooling systems?

 

I'm in the same boat.

Given I live up north, I rarely hit 190 - 210. My e-fan is wired to a toggle, that I never have to use. Perhaps the wrong t-stat is in it? It will creep up to 190's - 200's, then will cool right down upon acceleration. Don't know what the issue is. Doesn't really bother me.

As for your buddy... He probably had to do is head gasket because it overheated. He'll have to keep doing them too unit he fixed the real problem.

- Radiator flush

- New hoses/clamps (make sure the old ones aren't pinching on anything)

- Fan clutch

- T-stat

- Water pump

Don't think there's a whole lot more to do? Keep it oiled.

 

1st response is to verify with a thermo gun. Ive had broken sensors and gauges throw off my readings

 

I've got a 98 so no remix here, but threw a 180 thermostat and a 3 core radiator and I run 180-185 which is about 20cooler now so you might want to try the lower temp thermostat.

 

True comparing one to the other is hard, but mine i put a t stat i just got at advanced as far as i know its prob a 190, but ill verify a temp gun...

And on his, he got compression in his rad system, blew his lower hose, but neither the gasket or head was cracked on his...idk, i just thought it was interesting

Other then that though both systems have all new hoses and clamps and are still setup to stock specs

 

He did put a 180 in it, to my knowledge he hasnt completely confirmed his cooling issue since gasket replacement, and hes planning on doing a 3 e fan setup and eliminating his mech fan.

I personally havent smelled anything either, no coolant boiling smell, no sweet exhaust, so i was confused but on the same happily oblivious to the reason behind my slightly low running temp lol

 

The 4.0L should run at 200 degrees, the operating temp. Engines are designed to run at specific temps due to thermal expansion and all that jazz. 180 termostats are not meant for the 4.0L

Edit: some people mistake overheating issues with air in the system which will block the flow of coolant

 

You say that and now that i thinl of it we didnt burp his...put on the to do list now!

 

A high coolant to water ratio will cause the temps to be higher. Water absorbs heat faster than anti-freeze/coolant does, but you need the anti-freeze/coolant to lubricate the water pump, to keep the engine block from rusting from the inside out, and the raise the boiling and freezing point of the the cooling system.

 

hi ,we had a few problems like this over here in high temps, turned out to be head gasket, but it was the holes in the head gasket where restricting the water flow around the head, new type head gasket and guess what, all fixed