Mechanical fan upgrade options (not electric)

My XJ is running a bit hot - I'm in Arizona, and when it hits 117, it's not fun... And yes, I know everyone will say the stock cooling system is adequate if everything in the world aligns properly; but the fact of the matter is, the jeep was really neglected before I got it, and before I go with a massive overhauling of the engine, I'd like to add a bit more cooling capacity.

The head has been swapped with a TUPY head, so the top end is nice/new/clean. The bottom end for this thing is probably still filthy as all sin (jeep had massive amounts of sludge in it - thanks previous owner). I imagine the radiator and coolant passages in the block are not squeaky clean either... and despite flushing the whole thing, I don't think I can get them factory new clean without replacing components.

The temp will creep up past 210 in stop and go traffic. The fan clutch works as it should right now; so there's no reason to suspect that as the reason. I would still like to do the ZJ clutch swap and when I do, I would like to go with a bigger 3 core radiator. May do a higher flow water pump as well while I'm in there. The only piece that leaves to swap out is the derpy looking mechanical fan 5 blade setup.

I'm not a "fan" of the flex-a-lite stuff, but would like something with more than 5 blades/that moves more air. I don't care about the increased noise.

I've read on the grand cherokee forums about them using the GM 11 blade plastic fan. I have not found a single post of anyone attempting to put that on an XJ - do they fit?

If not, any other fans that fit in place of the 5 blade that move more air? From the looks of the 5 blade setup, it shouldn't be hard to improve on it...

Give the Grand Cherokee standard fan clutch a try first, it is partially engaged all the time and locks tighter than the XJ clutch, when hot, increasing the fan speed.
When it fully locks up, the power drain is noticeable .
It is noisy all the time but may be just what you need for the summer time.

The 1-1/2', 2-Core, HD Mopar radiator has worked fine for my Jeeps.
https://www.factorymoparparts.com/oem-parts/mopar-radiator-52080104ac

Mishimoto has recently release a HP aluminum radiator, a few here supposedly have tried them.
https://www.mishimoto.com/jeep-cher...ishimoto.com/search-simple-2000-Jeep-Cherokee

Hood vents work well for lowering temperatures when using an all stock cooling system.

http://www.jeepforum.com/forum/f13/explorer-fan-3364770/

When I did my radiator a few years ago I was looking into a high flow water pump. What I gathered is that it's us less for trying to run cooler since faster flowing liquid won't have the time to cool down in the radiator

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cody4359 said:

When I did my radiator a few years ago I was looking into a high flow water pump. What I gathered is that it's us less for trying to run cooler since faster flowing liquid won't have the time to cool down in the radiator

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That is wrong. If that was true we'd still be running around like old days with no water pump and hope the hot water rises to the top.

Tim_MN said:

Hood vents work well for lowering temperatures when using an all stock cooling system.

http://www.jeepforum.com/forum/f13/explorer-fan-3364770/

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Those are on the list down the road as well.

No plastic fans with more than 5 blades out there that fit the XJ - or no one tried the GM or explorer plastic fans?

Problem is there's not a lot of room for fan upgrades -- if you have bad motor mounts you might not even be able to fit the ZJ clutch

Does you electric fan work as it should? Are you sure?

You might be better served getting manual control of your E fan this way you can turn it on sooner and leave it on longer -- there is a thread around here on how to do it properly

Fosters said:

The head has been swapped with a TUPY head, so the top end is nice/new/clean.

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Might want to tell us what year, but by the "tupy" I'm assuming 2000-01!
Do you have "pre-cats"?

Since you are in AZ re route your trans cooler to bypass the radiator with an external cooler. That would be something to help across the board.


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Heavyopp said:

Problem is there's not a lot of room for fan upgrades -- if you have bad motor mounts you might not even be able to fit the ZJ clutch

Does you electric fan work as it should? Are you sure?

You might be better served getting manual control of your E fan this way you can turn it on sooner and leave it on longer -- there is a thread around here on how to do it properly

Click to expand...

Yep, e fan works ok, comes on with AC or by itself. Does suck with the room in there...

RCP Phx said:

Might want to tell us what year, but by the "tupy" I'm assuming 2000-01!
Do you have "pre-cats"?

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2001 and yes, i have pre-cats. The head that came on it wasn't a TUPY one and I thought the overheating and the oil pressure was the head, but after seeing how filthy and sludgy it was, I'm not sure it was cracked, probably just oil passages clogged... changed the head, oil pressure takes a lot longer to drop, and i wanna say it runs longer until it starts rising past 210 but it still does it.

themauler said:

Since you are in AZ re route your trans cooler to bypass the radiator with an external cooler. That would be something to help across the board.


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I thought about that - would like to get a trans cooler below the radiator - that part is about 5-7in tall and 18" long, and I know some superduties have trans coolers long and skinny like that... Gotta get a measuring tape to the junkyard I guess. Only problem that's kinda held me back from doing that is the lack of 5-6" automotive grade fans... I don't wanna rig computer fans in there :laugh:

Are there any other places where people mount trans coolers with maybe room for an 8"-12" fan? Those are a dime a dozen...

I just wanna have all of the parts lined up for when I tear into it - so all advice and input is greatly appreciated

Don't bother with tube/fin coolers. get a plate/fin cooler. Just went thru this, my 2000 was perfect for 15yrs when all hell broke loose. My fix cost about 8K$, but thing you can do for free are to make everything including the heart coil is working properly. You can also "port" the t-stat housing.

Here's my latest cooling mod thread! https://naxja.org/forum/showthread.php?t=1148286

My 2001 (4.6, AW4) has the two mini-cats and the associated under hood temps.
The cooling system consist of the HD Mopar radiator, a Hesco water pump, stock fan clutch, ported thermostat housing, hood vents, two coolers (transmission and steering) mounted in front of the radiator plus the A/C condenser . The electric fan can be switched on manually.
The transmission fluid does not pass through the radiator in the summer but is reconnected in the winter, to keep the fluid warm.
The cowl intake helps some by providing cooler intake air.

It runs in the 200-205 range, or lower, most of time. We just got back from ten days on the Eastern Sierra, where it was hot, seeing 225 only on long, low-speed ascents.
The temps are monitored with a ScanGauge and a separate oil temperature gauge that has two selectible sensors, one in the pan, the other measuring the fluid exiting the trans, before it heads to the cooler.
It's good to keep accurate track of the temps.

Here in Florida do not get as hot as Arizona but we do get our fair share of high temperatures. A properly maintained cooling system coupled to a good quality radiator goes a long way toward keeping the 4.0L temps to reasonable levels. The radiator in my XJ have 2 rows by 1.5" tubes and is of copper brass construction. It is now 14 years and is on its last mile,...some of the fins are beginning to let go from the tubes.

My XJ have dual electric cooling fans since 2004 and I am satisfied with them. Together they are listed at 4,000 CFM. I think the OEM fan clutch produces more but reliable data is difficult to come by.

The AW4 oil do not pass through the radiator. I have added plate type cooler and temperature controlled fan switch for that duty.

Fosters,....
small electric fans are available from Derale.I got them from Summit racing.

What gears and tire size?

I use stock rad and such. I live in palm springs CA, right now are temps are around 120. My jeep pulling a 2 mile slow grade it hit 205 and this is with the AC on. I have mine flushed every 3 to 4 years. They have better stuff for cleaning a rad.The rad shop that is.

HTH

RCP Phx said:

What gears and tire size?

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First, 3.55 with 225 70 15 then 3.55 with 30 X 9.5 x 15 then 4.10 with 31 X 10.5 x 15 now 4.10 with JK take off's 255 X 75 X 17. Engine temps about the same, fuel mileage varies.
The XJ have not been out of Florida with 17's but traveled extensively from Key West to Jacksonville and all points between. That is all flat road with the highest point being about or maybe less than 100 ft above sea level.

RCP Phx said:

What gears and tire size?

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I meant this for the OP!

RCP Phx said:

What gears and tire size?

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3.73s and 30" tires. :sad1: Soon to go all crazy to 31s

So to recap, I'll be doing a thicker/nicer/aluminum end caps radiator; put the ZJ clutch on with the stock derp-a-derp 2+3 blade fan, and look for a long and thin plate style oil cooler for the tranny to move that out of there.

The thermostat housing seems to be made out of cheese - i cracked the stock one when I looked at it the wrong way during the head swap... Don't think I'll try to port that

scottmcneal said:

I use stock rad and such. I live in palm springs CA, right now are temps are around 120. My jeep pulling a 2 mile slow grade it hit 205 and this is with the AC on. I have mine flushed every 3 to 4 years. They have better stuff for cleaning a rad.The rad shop that is.

HTH

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I don't think it's worth it for me to pay them to clean out a 17 year old stock radiator... If someone could clean the block coolant passages though, I'd be all over it

Anyone use any separate oil coolers to try and get more temp out of the engine through the oil?

And where do you guys install the tranny coolers? I'd rather not install it in front of the radiator/ac condenser. So far the best spot looks to be under the radiator.

You can't pull enough heat anywhere but in front of the radiator.

techno1154 said:

Here in Florida do not get as hot as Arizona but we do get our fair share of high temperatures. A properly maintained cooling system coupled to a good quality radiator goes a long way toward keeping the 4.0L temps to reasonable levels. The radiator in my XJ have 2 rows by 1.5" tubes and is of copper brass construction. It is now 14 years and is on its last mile,...some of the fins are beginning to let go from the tubes.

My XJ have dual electric cooling fans since 2004 and I am satisfied with them. Together they are listed at 4,000 CFM. I think the OEM fan clutch produces more but reliable data is difficult to come by.

The AW4 oil do not pass through the radiator. I have added plate type cooler and temperature controlled fan switch for that duty.

Fosters,....
small electric fans are available from Derale.I got them from Summit racing.

Click to expand...

I tried using a similar fan in the stock mechanical fan shroud. My results in the SoCal deserts and mountains were decidedly sub par. Unless you can get a fan that moves a LOT of air (Taurus fan, for example), you're going to have problems with temperatures.

Fosters said:

Anyone use any separate oil coolers to try and get more temp out of the engine through the oil?

And where do you guys install the tranny coolers? I'd rather not install it in front of the radiator/ac condenser. So far the best spot looks to be under the radiator.

Click to expand...

Oil coolers are extremely effective for reducing overall engine temperatures.

My transmission cooler is in front of the radiator. Putting it on the passenger side reduces the impact on the radiator as the difference in temperature is still high. Air leaving the trans cooler is going to be 30*-ish above ambient, and when running hot, the radiator is 200*+.


ZJ fan and hood vents have kept my XJ cool even in the local deserts when it was 100*+ and at 3-4000 feet and the AC cranking.