[Scottso699]

Recently I was asked about about some cooling modifications I added to my Grand Cherokee

- I have 5.9L that came with an electric fan - the fan burned out almost a month after I got it..... so I obviously had to replace it. Also when driving this beast I noticed that it drove normally at 210 degrees. I bit hot for my liking - when I put the AC on it jumped up to almost 240 sometimes! This had to go. I replaced the orginial fan first off with a cheaper 16 inch fan from Jegs - no name brand - don't do that. Buy a quality name brand. This fan burned out after only a couple of months! But I had attached it to my radiator like the directions said and found it really wasn't doing a hole lot. For those of you who are not familier with a 5.9L - they come with 2 speed electric fan that is supposed to go on and off different speeds too - at a secret temperature - that even the deal doesn't know! Figure that one out? But reguardless the tempurature it goes on and off at is way too high again for my liking. Along with these fans were two heavy duty relays located next to the battery. Now this fan must have been a monster to power because the wiring is at least 14 gauge wire and there is an 80! yes 80 amp fuse in the fuse pannel under the hood next to the battery. The fan, which is very heavy, is attached to a specially made fan shroud for the 5.9s. The dealer could order the parts to replace my fan but he said it would have been upwards of $500! - no thanks. I will get a better one and upgrade the cooling.

So what I did was remove the old cooling fan from the shroud and attached the new one to the radiator. This didn't do much as there was no suction around the shroud and the fan was only pulling air through one spot. - then it made the desicion for me to move it by buring out. Jegs reluctantly took back the fan with no box for a credit for a new one. This time I got Flex-a-lite Syclone Fan. Here are the specs below from Jegs' page.

Fan Diameter: 16''
Max. RPM: 2380
Airflow: 2500 CFM
AMP Draw: 17.0
Size: 16-5/8'' x 15-3/4'' x 4''
400-398 16'' Diameter Syclone-HP Electric Fan $119.99

It's a bit on the expensive side but suck it up and get the good one. - it will last longer! What did was cut out (using a hack saw and air cut off wheel) the webing on the fan shroud that was there so you don't put your fingers in the fan so I could attach the new fan to the shroud. I then put the new fan up the shroud and and messured where I needed to cut groves to attach the new fans mounting hardware. Once I cut the slots I put the fan there and marked where I needed to drill holes to attach the fan - I drilled the holes and attached the fan with MACHINE SCREWS, WASHERS AND NUTS not the plastic crap ties it came with. This will last longer - for those of you who go off road - if you use the plastic ties with the fan being as heavy it is (MUCH lighter than the original though!) it will break them after a couple of good bumps and bangs. Use screws. Take my word for it.

Now if you want you can add a fan to the front too - If you don't want to skip to wiring. I did this as over kill being that I have the 5.9L and I am obsessed with cooling. To do this you need some time. I got a Derale 12 inch fan from my neighbor for nothing... but for you it might cost about $70? Maybe more - Derale is a bit pricy. This will take a bit of Fabrication so you might want to go with a 10 inch for more wiggle room.

Start by removing your front grill and then the drivers side brace for the radiator that looks like a upside down V. You will need to remove the upper radiator support too so detatch the passenger side side upside down V from the support but leave it in place on the frame. I have an auxillary Tranny cooler on the passengers side so that will stay there. (I added this because Jeep decided not to add auxillary coolers in 98 model year - STUPID - anyone doing towing - offroading and you don't have an auxillary? Stop reading and go buy one and put it on, then come back and finish this. YOU NEED ONE or your tranny will fry up. But anyway - you can put this fan on either side depending on whether your cooler is on the left or right. Preferably to put the fan on the Drivers side as that is where the radiator is the hottest with a V8 and on the Passenger side for an I-6 because that is where that is the hottest. This fan will be attached to the AC core so you need to seperate the two after you have removed the cross support holding the radiator by removing the two bolts on the side. - At the same time remove all that rubber crap that runs from the top to bottom of the radator keeping the hot air in your engine compartment. - not to be confused with the rubber lining between the radiator and AC Core. leave that. you need it. You can mount this fan with the provided attaching hareware - its not going anywhere - anyone reading this knows that there is about 3 inches of room between the front grill and AC core. To get this fan in there you will have to move the radiator and AC core towards the engine and slip it in there - attach it to the AC Core. Now you need to cut the upper Radiator support to fit the fan in there. This is trial and error - keep doing this until the upper support fits and does not touch the fan. Once this is accomplished reattach the AC core to the radiator and but do not put the radiator support on yet. To get the main fan in you will need to pull the whole radiator towards you to fit it past the water pump pully (where your mechanically belt driven fan would be if you have a 5.9 or where it was if you have a 4.0 or 5.2) once you have it in there then reconnect the upper radiator support and reattach the fan shroud to the upper support. Now we have to wire. Fun Fun Fun.

For this you need to know your way around the block when it comes to electrical work. You need a electric fan switch with a temperature probe. Preferably an adjustable one you can set. you want to put this right at the intake hose for the radiator so you get the best reading. there are directions that come with the switch on how to install it in the radiator. Follow them. You will need to connect one wire to a Keyed power source and one to the AC compressor if yours has an AC relay like mine. Mine came with two wires to run dual fans. This is ok.... but for heavy duty over kill like I am - I used the relay that came with the Jeep - I connected the wire that would ordinarily go to the fan to the + side of the stock relay. This will be the wire that will turn on the fan relay. For those of you who have a 5.9 - attach the wiring of the primary electric fan to the wire that originally was connected to the original fan. NOW - there are two relays. If you are planning on using one of the tow relays you must match the power wire from the relay with the one that you are connecting the fan to. The Wires are Black, Red or Green - use a volt meter to pick the right one and splice the wire in. For those of you who don't have the relays in your car - you can buy one at Radio Shack to use. These are 30 amp relays. I have toasted 3 before I figured out to use the stock ones - so you may want to look into a bigger higher amp relay. To wire the second fan - connect ground to a ground source and if you have one like mine - I got it at Pep Boys - $40 - connect it to the other fan lead directly - this fan has less of a power draw and there is a 25 amp fuse inline with this. As for your 80 Amp Fuse under the fuse box cover for those of you with 5.9s - replace it with a 30 - by the time 80 amps happens with this fan your car will be on fire. If you have a 4.0 or 5.2 put in an inline fuse of 30 amps. All of your Power + wires can be connected at the fuse pannel under the hood on the end of it.

Now you have two fans. There is one more step to get your jeep cooler. Thermostat. If you cant get coolant flowing though the radiator what the hell good are two fans???? I installed a 160 degree thermostat. The stock on is a 195 degree. Most common are 180 replacements so you might have to dig for a 160 - Turbo City sells a high flow for about $10 - for all you V8 guys you will need to modify your intake a bit to make the thermostat fit correctly 4.0 guys it i will be fine - you can modify it easily with a file as your intake is made of soft aluminum - DON'T GET THE SHAVINGS IN THE COOLANT! Stick a paper towel or rag in there if you plan to do this modification. But anyway - the difference you will notice is amazing. Your temp gauge will go from 210 to about 155 in the winter and inbetween 155 and 182.5 in the summer - only with the AC on does my Jeep get to 210. In the future I have plans for a 3 row metal radiator for ultimate cooling.

Also as a side note I have a remote oil filter system with a perma-cool heavy duty oil cooler inline with it. The oil filter is where the air box used to be - I also removed all rubber insulation around the hood to allow air to freely flow throughout the engine compartment - I also changed the water pump to a HI FLOW water pump from Flowkooler

- check it all out at www.cardomain.com/ride/771987

If I left anything out or there is confussion let me know

Scott

98 5.9L
4.5 Rubicon Express Super Flex
265/75/R16 Firestone Destination M/Ts
Mopar Performance PCM
Turbo City Dual Air Intake
Turbo City 52mm Throttle Body
Turbo City 160 Degree Thermostat
MSD Blaster SS Coil
MSD 8.5mm Wires
Drilled Brake Rotors
Hi-Flow Flowkooler Water Pump
16" Flexalite and 12" Derale electric Fans
Magna Flow 3" Cat
40 Series Flowmaster Muffler
Stock 3" tail Piping
Stainless Steel Brake Lines
NP242 Selec-trac Transfer Case

www.cardomain.com/ride/771987

[gregmondro]

very informative post!

[kemicalburns]

i think i will start with the 180* stat, and look into a fan maybe for the front first. just because my stock fan is working good right now

[HighLonesome]

Its cool that you want overkill on your cooling. And some nice ideas too.

I've read that 160 stats are no good...they don't let the motor warm up enough for the computer to be happy. You can trash your cylinder walls and rings from excess gasoline washing the lubricating oil away.

Not entirely familiar with the 5.9, but I know the 5.2, and your charging current likely flows through that 80 amp fuse. If it does, I would NOT replace it with a 30.

Your are toasting 30 amp relays? Not good. I wonder about the reliability of your electrical work, but I am anal about that kind of stuff.

Don't do the 3core radiator, they are junk.

Good luck to you.


Edit:

You can get the entire 5.9 fan/shroud from www.buymopar.com for around $200. $500 is highway larceny.

[Scottso699]

Originally Posted by five.two

Its cool that you want overkill on your cooling. And some nice ideas too.

I've read that 160 stats are no good...they don't let the motor warm up enough for the computer to be happy. You can trash your cylinder walls and rings from excess gasoline washing the lubricating oil away.

Not entirely familiar with the 5.9, but I know the 5.2, and your charging current likely flows through that 80 amp fuse. If it does, I would NOT replace it with a 30.

Your are toasting 30 amp relays? Not good. I wonder about the reliability of your electrical work, but I am anal about that kind of stuff.

Don't do the 3core radiator, they are junk.

Good luck to you.


Edit:

You can get the entire 5.9 fan/shroud from www.buymopar.com for around $200. $500 is highway larceny.

I have never had a problem using the 160 degree Thermostat - I used it on my previous 4.0L too - because it gets so hot in the summer time - warming up is never a problem with this thing. The 5.9 in the 98 model is a sourced R/T Engine with an advanced timing so it needs 92 or better gas which will burn hotter anyway making it run at a bit higher pace than a 5.2 using regular gas.

As for the 80 amp fuse it says right in the fuse box cover "aux cooling fan" and for the relays I was running 2 fans on one relay - to many amps for one to handle - and as for my wiring it was all done with 14 gauge or larger wire. And I am very anal as well about my wiring as everyone should be when modifying stock configurations.

I'd like to know why you think a 3 row radiator is junk though - I'd like to get more info on that.

[Scottso699]

Just a reminder too - the charging system on a 5.9L came stock with a 180 amp alternator used with an Optima Deep cycle Yellow Top Battery - standard Grand Cherokee V8s come with a 100 - 130 amp alternators depending on years so adding high amp drawing accessories can put a serious draw on you system.

[HighLonesome]

Originally Posted by Scottso699

I'd like to know why you think a 3 row radiator is junk though - I'd like to get more info on that.

I had a CSF 3core that blew a seam, and the e-stories abound about them leaking sooner or later. I know they have a lifetime warranty, but who enjoys radiator swaps? And they don't cool as good as the OEM rad IMO.

As for the 160 stat, you should verify that the computer is switching to closed-loop operation, especially in the winter. And if you are not running at 160, then the 160 stat is doing nothing.

BTW, I like your site and your Jeep is nice.

[HighLonesome]

Originally Posted by Scottso699

Just a reminder too - the charging system on a 5.9L came stock with a 180 amp alternator used with an Optima Deep cycle Yellow Top Battery - standard Grand Cherokee V8s come with a 100 - 130 amp alternators depending on years so adding high amp drawing accessories can put a serious draw on you system.

The stock 5.9 alt is 150 amps.

I believe the early 5.2s came with a 90 amp and the later ones with a 120 amp. Yes, the 5.9 efan has a serious draw, but that's why it moves so much air.

[josephmartins]

But I had attached it to my radiator like the directions said and found it really wasn't doing a hole lot. For those of you who are not familier with a 5.9L - they come with 2 speed electric fan that is supposed to go on and off different speeds too - at a secret temperature - that even the deal doesn't know!

I believe several months ago Frank? sent me a printout of the 5.9 temp settings straight from the factory service manual. At the time I was considering doing a full-blown 5.9 e-fan swap into my 97 ZJ. Turns out there's a much easier way. Buy a used 5.9 e-fan and shroud and install it along with a Flex-a-lite thermostatic controller (thanks to Nick over at Kolak Performance for the tip).

Though I never got to do the swap, Nick says it works beautifully. I still have the fan and shroud and controller sitting in a box in the basement if anyone wants to do this conversion on their ZJ. I just don't have any time to do it myself.