Sudden Overheating issue

Hi guys, so I am having an issue with sudden overheating. My jeep overheated pretty bad last summer, so about two months ago I replaced the fan clutch, AC electrical fan and the belt and did a full coolant flush and the jeep has been running great with cold AC and the needle never going above half. Then today on my drive home it crept up to the halfway mark and I smelled what I think is a burning rubber smell. Then at stoplights the temp kept climbing until I started driving, and then it would go back to the halfway point but not lower. I popped the hood when I got home and the belt is spinning fine and the burning rubber smell is still kind of noticeable but not over powering, and I am not leaking any coolant anywhere that I can see. Any ideas? Did the water pump possibly fail? I also changed the thermostat when I did the other fixes.

Halfway mark...as in 210? Pretty normal for summertime. Summers' out here are usually 90-110F (today, and all weekend supposed to be 100-105) and both my XJ and MJ run at 195 to 215 depending on what kind of load, like steep grades, or hauling a trailer, or loaded with camping gear and a canoe. Cooler on flat and straight, hotter in the hills. Especially when running the A/C When I'm up in the REAL mountains at 6-9,000 elevation on a 6-8% grade on a dirt/gravel trail going 20-25 mph. The E-fan should go on at ~ 218, you're not getting that hot, so you're good. The e-fan should come on with the A/C too.

I would not call that overheating, Id' call it normal summer driving, especially in an XJ/MJ. If you're concerned though go through the regular troubleshooting and maintenance items. A rubber smell could be a sticky or rough pulley restricting the belt, the belt too tight etc. How old is your radiator? If the temp is creeping up while slow n' go, or sitting in traffic the fan clutch is suspect.

Oh, and since you're not including the year, engine etc. info, it's harder to answer your questions...just guessing.

It is going well above the mid mark.

Sounds to me as if you are not yet finished with the cooling system overhaul after overheating. How many miles are on the water pump and radiator ? Is the e-fan turning ON ?

Climbing temps at slow speed or idle, suggest lack of either air flow or lack of coolant flow. Since you have a fresh mechanical fan clutch, you should suspect the radiator and/or water pump. If you do one, do the other at the same time.

I've never replaced the Water pump in the three years I have owned the jeep. The E fan does kick on the moment the AC is turned on and the new fan clutch is definitely pushing air. There is not a coolant leak and the fluid tested perfect. I'm Definitely thinking water pump.

What year is it?

Lets focus on the burning rubber smell first (assuming it is rubber and not coolant?). I would pull the belt (enough to test each bearing item the pulley rides on) and see if all the stuff rotates freely, water pump, idler pulley, AC clutch pulley, power steering pump and alternator.

Follow that odor to its source on a fresh start!!! Is it coolant or oil burning on the exhaust manifold? Or the e-fan motor smoking?

When it is cold, pull the radiator cap (Replace the Cap then as well) and see if you can see good coolant flow once the T-Stat opens? If the level drops (after the T-stat opens the top Rad hose is hot!!) and you do not see good flow from the Rad core tubes, the radiator tubes may be clogged.

Get an infrared temp tester, Harbor Freight has very low cost ones, about $20 and check the drives side temps (Pull the e-fan maybe, do a cold start, and test for cold spots once the T-Stat opens and hot coolant starts to flow.

Also clean any junk (leaves, bugs...) that you can out of the outside fins/tubes in the A/C condenser and Radiator.

Okay guys, just a bit of an update. I went ahead yesterday and pulled the front fascia off and removed the radiator and all other cooling bits I hadn't replaced. I took the rad to a shop and they tested it and cleaned it and said it was working well. I replaced the water pump with a new one, not a reman unit and used high temp copper rtv in a thin layer to help keep the gasket in place. I reassembled everything and had no parts or random bolts left overparty1:. I started it and burped it and no longer have a burning rubber smell and the temp is just under the 210 mark after warming fully and sitting in my 90 degree garage just idling.

I do have one question, I turned the heat on and put the temp to hot and the fan all the way up and nothing came out of the vents, if I switched the control to defrost it did, but move the lever back to heat and nothing. What could that be?

Air outlets are controlled by vacuum to individual diaphragms. Defrost is the default outlet, so if it stays there all the time you have low vacuum pressure into the head unit. Probably a leak somewhere.