Hi,
Recently I have made some modifications to my cooling system. In the spring I drove on the beach and quickly realized I needed to make some improvements.
This is setup I ended up with after I made my initial modifications.
radiator: thermostat: 180F
radiator cap: cap
I also put in a new stock water pump.
It seemed to do fine as long as I stayed moving. It ran around 185-195. I became worried when I was sitting in a drive through on a hot day and it overheated. ~230F (too hot for me)
I was thinking maybe with the larger radiator the water pump is having trouble pushing the fluid fast enough to keep it cool. Also, I was thinking that although the specs on the fans stated it would flow better than the stock setup, maybe they were not performing to the stated spec.
To try and improve the cooling performance I order the following parts.
1 higher flowing fan. I went with the lower profile due to some clearance issues: low profile fan I can tell that it flows better than the previous fan.
Another high flowing fan. I didn't have clearance issues so I went with the highest flowing one I could find. It definitely flows better than before: high flow fan
Lastly I put a high flow water pump in: high flow water pump
It seemed to run cooler for the first few days, 180-190F But today it seemed to not like the hot day. It got to ~215F. If I would've sat at the stop light longer it could've gotten even hotter.. Not sure though.
I am worried that when I drive on the beach in some rough sand on a hot day I'm gonna run into some over heating problems again.
Fyi, when it hot I was running my a/c. I understand that keeping that off will help, which I will in offroad conditions, but it concerns me I see these problems in daily driving situations.
Also, I'm running ~90% anti-freeze 10% water (green).

Am I gonna have to except that keeping it below 210F in tough conditions is unrealistic or could something else be going on? Thanks in advance for any comments or advice.

 

Most here find that a stock cooling system that is operating at peak efficiency works fine except in the most extreme operating conditions. I can leave my '96 idling for extended periods with the a/c on in the hottest weather without it overheating. Not saying you should go back to a stock system but some have experienced problems after modifying the oem system.

 

You don't need a larger water pump etc. The thermostat acts as a restrictor and metering device. If you remove it, the fluid moves too fast and you get a cold engine on cold days and hot engine on hot days. If you want to improve your cooling, a larger radiator and big fans will help. But the fans need to move more than 3000 cfm total or you haven't gained a thing. Taurus fan for example moves 3800 cfm on high speed and is generally an improvement if you used it with a shroud.

 

Go back to an OEM setup. The stock clutch style fan rips at over 4000 CFM & the stock E Fan is rated at 900 CFM. Good luck finding an "Upgrade". The OEM style radiator is excellent as well, especially the HD version, if you can find one (looks like RockAuto is sold out). The Flowkooler water pump isn't a problem, they work fine. They use the same housing as everyone else, they just have a billet impeller with more vanes than most other pumps. The only mod I would recommend for Cherokee cooling is a manual override switch for the E Fan, so you can turn it on and leave it on for those warm days.

 

If your running fine on the highway I'd say the radiator is fine but those fans seem a little weak especially being 9inch fans. Also there is no reason you should be running 90% antifreeze. You mentioned beach so 10% antifreeze would be better for warm climates. It's got the word freeze in it but doesn't make your vehicle run cooler than water. Nothing wrong with the flowkooler pump. Old ones had issues but they have been fixed.

 

Sounds like you took an well-engineered system and threw parts at it until it was no longer well-engineered

What was the condition of the system before you made changes and what symptoms led you to make changes? I'm assuming overheating at low speed while driving on the beach. Did you try some maintenance first such as doing a really good system flush and replacing your fan clutch? Did you have an intact fan shroud? Was your electric fan operational?

Steps I would take:
-replace your coolant with 50/50 antifreeze/water. Why do you have 90/10? Water is better at cooling. Add some Watter Wettter if you're feeling it.
-replace your thermostat with the correct 195°F temperature range. Running cooler than designed for is detrimental to performance.
-replace your OEM mechanical fan with a new fan clutch and shroud or a properly spec'd electric fan setup with a well-designed shroud.

Overheating at low speed and not at high speed indicates lack of air flow across the radiator.

 

Go back to 50/50 antifreeze/water, or even 40/60 antifreeze/water. I've tried water wetter, and saw no obvious difference in water temperature, but I don't necessarily think that means its useless. The value is limiting nucleate boiling in the cooling passages in the motor to help with heat transfer.

When I first picked up my 2000 XJ a few months ago, it had a 195F tstat, and it would run at 210-220F all the time. I'm now running a 180F tstat on an otherwise stock cooling system in good shape and with fresh coolant. It holds at 195F during driving on flat ground, but it will warm to 210-215F when driving on long hills on the road and when on the trail. When idling in warm weather after everything is fully heated up, it will warm to 220F, but as soon as the efan kicks in, the temp will drop to 210F. I think the primary challenge with running the 180F stat is that the mechanical fan clutch and the efan are both designed to work with a 195F tstat. If you want to control to a 180F tstat, I think its necessary to modify the behavior of the cooling fans. Its relatively easy to modify the efan behavior, but no way to mod the fan clutch expect perhaps to use the ZJ fan clutch. Main point for this paragraph is that don't expect to control to a 180F tstat for all conditions without making some additional mods.