RipPow99XJ

Hey, so I've driven my Jeep across the country without overheating. I've driven it elsewhere without overheating. I've had my radiator flushed and new coolant added. She specifically is overheating while traveling up both Big and Little Cottonwood Canyons in UT while snowing heavily. I've noticed when I pull over, it looks like the radiator grills up front are coated with snow. Common sense tells me this is restricting airflow, but why doesn't it melt the snow? Shouldn't the radiator be warm enough to melt it? After pulling over and letting her cool off, I've been able to finish my uphill climb without overheating again. Is this something I can fix or is it an XJ thing I'll have to learn to live with?

FIXED: New radiator

Ralph77

I guess my first questions would be is your fan clutch operating properly, is the electric fan operating properly, and do you have the shroud around the mechanical fan?

cruiser54

How old is the radiator cap?

RipPow99XJ

​​​​​​​
The fan was spinning the last couple times it overheated. The shroud is around the fan. The radiator cap could be as old as the Jeep. I only got it in Sept '21 and haven't changed it. What could the cap have to do with overheating?

cruiser54

The cap needs to hold 16 pounds of pressure or the coolant will boil...https://oards.com/bad-radiator-cap-symptoms/

RipPow99XJ

Hmmm, my coolant did boil over out of the overflow reservoir when I first overheated. I'll replace the cap and report results next time I'm in a snowy/uphill scenario. Thanks!

cruiser54

Good plan.

Rogue4x4

X2

Rad cap is the most overlooked part of the cooling system, and the cheapest and easiest to replace. Irony.

RipPow99XJ

Alright, so she overheated again on the same stretch of uphill as before. No 4wd engaged, no snow, sunny day around 40°F. It did not boil over this time. I noticed the check gauges light came on and the needle was just touching the red as I arrived at my destination. Note, this was in Little Cottonwood Canyon in UT. As stated previously, the radiator was recently flushed and the cap was replaced. I'm beginning to lean towards my assumption that the XJ just can't handle these long stretches of uphill climbing without any breaks, but am open to other ideas.
Edit: I read another forum where a new Mopar radiator and water pump did the trick. I did have the water pump replaced when it burst traveling across country. Maybe they replaced it with a non-oem pump. Hmmm

MaskedMallard

Is your XJ stock? When checking coolant, are you opening the metal radiator cap on a cold engine & making sure the coolant is about to flow out of the top of the radiator? Does your temperature gauge stay at about the 210*F once warmed up, or does it fluctuate up & down?

Is the radiator unobstructed? Maybe, with the engine off & cold, you could blow compressed air from the engine bay towards the front of the Jeep, to blow out any contaminations in the condenser & the radiator gills.

My XJ used to run just on the plus side of 210*F. I did the following to it & didn’t have any issues in the late summer, while in Yellowstone National Park.
- High Flow Water pump (www.hesco.us).
- High Flow Thermostat Housing (www.hesco.us).
- Thermostat with steam hole (www.hesco.us).
- 3 row radiator.
- new radiator cap.
- external transmission cooler.
- water wetter.

Now the XJ runs just on the minus side of the 210*F.

cruiser54

My Jeeps don't overheat on a steady climb up Sunset Point when it's over 100*F. Your issue is NOT normal.
Your radiator may have been flushed, but I doubt it's clean.
What did the coolant look like when you flushed it?
Maybe the impeller is rusted away on the water pump and your radiator is still packed with crap in the bottom. Typical of cross-flow radiators.

tech

When going up and the engine is getting hot can you hear the engine fan ? if you can't hear the fan I would say that the fan clutch is bad if it is old I would replace it ,

RipPow99XJ

Yes, my XJ is stock. I just opened up the metal rad cap after my jeep was sitting all night. Aside from it being a warm day, it's a "cold" engine. Yes, the coolant was at the top. The temp gauge usually gets to just over the 210F mark and will stay there, doesn't fluctuate much once that point is reached aside from the overheating. The radiator has a crap ton of bugs in it and some of the fins are bent. I'm also remembering now that I used some Bar's stop leak when I first got the Jeep and realized the heater core was bad. I've since replaced the heater core(fun stuff!).
When I had the coolant flushed, I was told it was very dirty. When I checked just a few minutes ago, It looked clean beneath the metal cap, but looked a tad murky in the overflow reservoir. The water pump was replaced within the last 5k miles.
I believe the fan is kicking on. I hear it turn on and off all the time and I know that I have to turn my engine off to spray belt dressing on(squeaky belt) because it blew back in my face last time, lol. Thank you for your replies. Looks like I've got a few parts to replace before I can draw any more conclusions.
Edit: The fans work. Both fans are spinning

RipPow99XJ

Update: Radiator flush did not help. Flushed once, very dirty fluid came out, ran with distilled water and Blue Devil flush for about a week, flushed again and filled with half distilled water half coolant concentrate. Again, on a steady climb up I80 E from Salt Lake heading to Park City she overheated. Boiled out the overflow. Next up is the thermostat

tech

How old is the radiator ? it mite need to be replaced it could plugged up so much that a flush is not going to clean it .