XJlimitedx99

Doh! I didn't even notice it was missing (not sure if I even looked at the picture).

Definitely get a shroud on there first. That will help the fan pull air through the radiator more efficiently. If your issues aren't resolved after then look into doing a fan clutch.

nickfancher1

Also, buy a fanshroud online like on Amazon or RockAuto, I think they're only $16 or so. What happens is over the years the plastic gets brittle and people just don't put them back in when they break.

They have 2 little feet that slide down into the bottom retainer things on the radiator, and each use 2 screws to hold the tops in.

Tbone289

I would just go ahead and put a new fan clutch in when you put in the new shroud. There's pretty much no way that an original fan clutch is still working well.

mannydantyla

Fan shroud is like $16 online + s&h, I just bought and installed one because the last one broke. The electric fan is like $50 iirc. By the way, I tested the stock electric cooling fan (1997 xj) against a 10" aftermarket one from Jegs and the stock one blew more air. Just measured with my hand so not scientific or anything, but I returned the aftermarket fan.

But to answer the question, the cooling system can be improved three ways that I know of:

1. A bottle of Redline Water Wetter added to the coolant, and run more water than antifreeze.
2. Bigger radiator. Some say the radiator is too small, others swear that it's more than enough. All I know is that a bigger radiator will take more heat out of the coolant than a smaller one.
3. Hood vents. Extracting the hot air from under the hood can only help. Can it help enough to lower the coolant temperature? I don't know

I'm not saying that the xj NEEDS those three things to run cool enough, those are just general improvements for any vehicle

What about swapping the mechanic fan for electric fan(s)? Electric cooling fans can help when idling, because the mechanical fan is not spinning as hard, but at any other time the mechanical fan will always pull more air than electric fan replacement. As far as HP and MPG gains, you might see an increase but that's debatable I think as the alternator would now be pulling harder.

What about a high flow water pump? That's debatable. In general, I believe that the faster the water flows through the cooling system, the better it does at cooling the engine. Coolant does not need more time to sit in the engine to absorb heat or more time in the radiator to release heat. That's according to this source: https://www.flowkoolerwaterpumps.com/cooling_faq.html But that information is conflicting with this - http://www.felpro.com/technical/tecb...ant-holes.html - which says "the coolant can pass through the engine too quickly and fail to absorb enough heat [...] resulting in overheating." Which to believe? When replacing my head gasket, I noticed that all the vertical coolant passages (coolant flowing up from the block into the head) where blocked by the gasket or only had small holes in in the gasket, except for the two in the very back. So the engineers agree that the coolant can flow too fast, it seems.

I guess I've become sort of an XJ cooling system expert over the past year

outersketcher

Having lived most of my life in the deserts of Southern California. Where heavy traffic on the 91, or the 10 freeways would put you in a nasty heat situation. Essentially, you and your xj, baking on an overheated blacktop that has become so hot, the tar has become sticky again. Your temp sensor.. (you know.. the one that sits inside your front bumper.) Screams 116 F at you.

Yah.. those kinda days. I can tell you that if your stock cooling system is running properly. You don't NEED anything else. I commuted everyday, in heavy traffic, in heat like that.

I had problems at first.. till I made sure my fan shroud was bolted back on properly. I made sure my electric fan was working again. (had a bad connection) And I replaced my thermostat.

I also did some research on keeping a cool engine. One of the easiest ways to keep your engine running cool is to simply keep your engine clean. For an engine.. a thick layer of grease and sludge is like having to wear an overcoat in summer. That sludge is a WONDERFUL insulator. Keeping LOTS of unwanted heat trapped in your engine.


So, IMHO.. before you buy any extras and add-ons. First, flush your coolant and change your thermostat. Change your oil. Reinstall the fan shroud. And the electric fan along with IT'S fan shroud. Then clean your engine. Spray it down. whatever..

If you still have heating issues.. replace the mechanical fan clutch.

You shouldnt need anything else to run cool.

BlueRidgeMark

Outersketcher said it all.

EEVEE

funny thing about the grease and that. My jeep got toasty (and still kinda does) when it had alot of crud around the engine after i cleaned it off it cool off so much quicker and stayed cooler on 90 degree days with no humidity with alot it still gets toasty but not as much and a fan shroud that isnt broken does wonders along with a good fan clutch and imho dont but the very curved electric fan pay the little bit more for the different styled fan on rock auto it blows slightly more air than the one i bought and it suffers a little on baking hot days no overheat but can be improved if you dont mind a little louder fan as this one is very quiet but i prefer more air circulation. after i swapped them i noticed a difference in temp changes and it got hotter quickly so for giggles i stuck my old one in and jump started it and left it running with no bolts and such on a hot day and never budged past 210 so stuck my old one in and it got to the line after 210.

mikecorrell

investinwaffles

On the 97-99 XJ, the electric fan comes on when coolant hits like 220*F, or anytime the AC compressor is running. On the 00-01 XJ, it comes on at the same temp or when the AC refrigerant pressure is high enough on the hot side.
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I would flush the radiator (possibly replace with a Spectra factory replacement) and backflush the heater core too. Make sure the AC condenser and radiator are clear of any mud or bugs and stuff (ac coil cleaner works great if they are super dirty).

Make sure hoses are in good condition. Change out the stock fan clutch too if it's original. It's all just cheap insurance vs overheating on the side of the road.

If you live in a hot climate, run Shell Rotella T6 (5w40) or even Rotella T (15w40) and a Wix/Napa Gold 51515 oil filter for additional protection.

Tbone289

It's not quite the same temperature. 97-99 is 218 degrees, 00-01 is 223 degrees.


From the 2000 FSM:

Bugout4x4

Wow... My 97 has always came on like clockwork right when it hits 112 and shuts off at 110. My gauge must be off a few degrees.

Tbone289

Did you mean 212 and 210?


Monitoring OBD-II on my '00, it does exactly as the FSM says.

Bugout4x4

Lol... Thank you... YES... Not enough coffee yet...

mannydantyla

Man you guys are talking about cooling systems way too early in the morning...

EEVEE

very nice..... to test my fan i did a few donuts and sure enough it popped on... might work for ya