Radiator replacenent

OK all you XJ guru's! Gf's XJ is in need of a new radiator. Is there any that are beter than stock that I should be looking for? I have read that 3 core is not a great improvement. How about Aluminum? Its a 94 4.0 w/ ac. It runs approx. 200 / 215 on the average in hot weather or pulling the Mtns up here.
Is a high flow H2o pump worth the work? I have also seen a modified water inlet housing anyone tried this? The rig Will be getting hood vents soon! Thanks to all who help!

200-210 is what they are designed to run at. If its only getting that high on hot days or when driving in the mountains, I'd say the cooling system is doing its job.

Yes I do realize that , however its gonna really be a pain soldering all those missing fins back into tha radiator. :roll:

Oh, well that makes more sense. I'm running a Modine 2 row in my 95 and it really seems to cool a lot better than my OEM did. Its brass and all metal construction. It was a pretty straight forward installation and it bolted right in. I hope that helps more.

I installed a new radiator in my 88 XJ in the past couple of months. If the GFs XJ is gettng to 215 I'd think you may have a thermostat that been damaged by running warm.

I would replace the radiator with a new one. I installed a Modine this time, had a GDI last time but it came down with a leak between the tank and the fins. The modine is 2 cores which totaled 1.5 inches, the GDI is 3 cores which totaled 1.5 inches.

I heard a mechanic on the radio say a radiators life is 7 years, anything more is just gravy so you are due for a new radiator.

I'd replace these parts also:
* Fan clutch, there not good test for these and the word is they only last 5 years. This could explain why it runs warm, the fan not sucking enought air.
* Thermostat - buy a new 195F thermostat at the dealer, it comes with the vent hole and a very nice gasket with RTV pre applied. No need to have a tube on hand. Expect to pay $8-10 for the thermostat.
* Radiator cap - The spring could be heat damaged so put a new cap on that new radiator.
* Radiator hoses - I got mine at the dealer very nice. Expect to pay $40 for both hoses. The both comes with the antichafe on the outside and the lower comes with a full length spring.
* Fan belt - the radiator will be out and it will never be easier to change the belt and tension it. Also pick up a Kriket II bension gauge at NAPA. Belt tension on my 88 XJ is 180-200 lbs for a new belt. I currently use a goodyear gator back, has the ridges cut to reduce belt noise.
* Idle pulley - this may be rough and I picked up a new one at advance autoparts for $10, cheap insurance.
* coolant - use distilled water instead of tap water to mix with your anti-freeze. A guy who was a Army Nuclear reactor tech told me to use distilled water for radiators. Avoids introducing any minerals that can attach to the block or radiator and reduce how well the engine cools.

When you have the belt off spin all the accesories and replace anything with a rough bearing. Depending on the mileage you may want to change the water pump as preventive maintenance. I changed mine at 135,000 miles because I was not sure how long it would last. I installed a Hesco water pump since they siad their impeller pumped more coolant and free'd up HP and torque. You can read about them at www.hescosc.com. I recommend you install a new water pump, not a rebuild. Also do not over look the dealer as your source for a new pump. Do get the water pump gasket at the dealer, it like the themostat gasket with RTV pre applied. No need to apply any, I installed mine dry and no leaks 2 years laters. The Fel pro looked second class compared to the mopar gasket.

IF you change the water pump make sure to loosen the water pump pulley bolts before you loosen the belt. It makes life MUCH easier to do it then than after you remove the belt.

Disconnecting the trans cooler lines will require a speical tool. It called an AC line tool, you can get a set of 6 at sears for 6 bucks, you will need the 3/8 tool to remove the coupling if it all metal. If the coupling has plastic ears then you just press the ears against the line and pull.

I hope I have covered it all.

Thats super thanks ! Another question , has anyone eliminated the clutch fan for a permanant fan with any sucess?

If you are referring to an electric fan, a common upgrade is the flexalite 110. Its about the only electric fan that will fit it. This will probably stir up some debate since its a controversial subject. Many argue that the clutch fan is more effective in cooling than the electric fans. I tend to agree with them, but have never tried it personally.

Good luck.

over the years alot have done the mech to elec conversion to eliminate the mech fan, most have come back, some won't admit it does not work as well. The mech fan moves far more air than any of the electrics do, moves it better and moves it even after a fan motor has burned out. In a pinch you can get home with just the mech fan, not so if the electrics fail.
Martin has it down right [though that hesco water pump is not for me], the modine radiator line is a good product and after a certain milage when you need to replace some parts it's a good idea to just do all of them at once while you have it all apart instead of trying to 'sneak up' on the problem a piece at a time.
I have that to look forward to this summer, with 194,000mi on my 98 and now that I have a full gauge cluster I imagine I will probably see some cooling problems this summer, it's about that time. I figure one weekend will consist of flushing/cleaning, new rad. WP, hoses, tstat, cap and coolant. Belt is new as are the idlers and I will probably do a fan clutch as well while its all apart anyway.... Might even start ordering the stuff over the next few weeks and get ready for it.

My bad , I was refferring to replacing the mech. clutch fan with a non-clutch mech. fan. That bolts to the water pump in place of the clutchfan.
Yes I agree that all parts in the cooling family will be replaced. I have my list with me today to get them ordered. I am lucky that I have about 5 Jeep dealers that are sub-dealers of the company I work for. So I have a bit of an "in". Thanks To all!

Now that I've changed the tranny cooler from the stock inside the rad version to an outside version the XJ runs about 5-10 degrees cooler.

Sarge

Well thanks Guys for all the great advice! I just ordered all new parts from a dealer , should be here tomorrow! I ordered, both rad. hoses , t-stat & gasket , idler and radiator , all oem factory parts , and will be in for less than $250.00!


Woooooooooooooooooooooooooo hoooooooooooooooooooooooooo

I just did the rad on my 89 over the weekend. I used a 2 row Modine for a 91+ XJ, new waterpump (lifetime from Napa), new thermostat housing from a 91+, 180 deg thermostat from Napa and drilled a vent hole in it, new heater control valve for a 91+ XJ, new overflow tank again from a 91+ and then all new hoses. My temps on the freeway in traffic are sitting around 180 to 195 at the highest and I have seen around 170 cruising at 75. I am very happy with the results so far.

gr8lite,

You will find the mechanical fan does not attach to the water pump on the 4.0, it attaches to another bearing which is part of the AC mount bracket. There no cooling fan attached to the water pump.

I hope you replace the fan cluch like you hinted at in the prevous post. I would avoid the fixed mechanic fan. It will rob you of power when you need to pull on the highway.

I had a buddy who installed a fixed fan on his 90 mustang with the 5.0 because it was cheaper than a fan & fan clutch. After a week he paid the money for the new fan and fan clutch. It was bothering him how much slower the car accelerated with the fixed fan instaled.

It no more work to change the fan clutch since you will be removing it to change the radiator anyway.

Sounds like you are on the right path, I also noticed you did not list a radiator cap, hope you just left that out of the list.

OK I replaced everything , now what ? I put in radiator both rad hoses , t-stat , fan clutch , belt, idler , new A-freeze. Still showing on gauge 210! Are these gauges commonly bad? I am pretty p/o'd $250 bucks and no change! Any thought? Thanks to all!

Did you burp it ?? You need to get all the air out of the system. Easy way with the nose slightly uphill is to allow it to run, warm up and the tstat to open with the radiator cap off, keep the filler neck full of coolant. You will see what looks like fizzy green soda. That is the air coming out. As the air leaves the fluid will go down, just keep that neck filled. Takes about 40 minutes. Doing what you did you have ALOT of air in the cooling system.
Also, did you put on a new pressure cap, if the cap is weak at all it will not build up pressure and will run hotter.
At the end while the engine is running use your thumb on the throttle body to increase engine rpm's, the fluid in the rad neck will go down, top it off and get the cap on as quick as you can, this will force more air out when the engine shuts off and force more air out thru the overflow tank. Oh, make sure that overflow tank is filled to between the cold and hot marks. You did take that overflow tank out and clean it right ??? No sense in doing all that work and then putting old dirty coolant back in from a 3 or so year old overflow tank...

If air is the problem another thing that helps is to disconnect the top rad. hose at the thermostat. Hold the hose end as high as you can and fill it. Now stick it back on. Have a water hose handy to flush things as it is a little messy. When you do this, have the cap off the coolant bottle if this is the old style closed system. You'll know its full when the level starts rising in the coolant bottle.

gr8lite said:

Thats super thanks ! Another question , has anyone eliminated the clutch fan for a permanant fan with any sucess?

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Kind of late on the information, but I swapped my clutch fan for a flex fan. There aren’t any parts listed for this application and I couldn’t find anybody that had done it before, so I just took a stab at it and ordered the parts I thought I would need. I’m using a Perma Cool 15” reverse rotation flex fan and 2 ¼” spacer (Summit part # PRM-86150 & PRM-24225). Coming up with a small reverse rotation fan is a pain; the Perma Cool is the only one I could find that would fit the bill. The 2 ¼” spacer is a little bit too long and I’m getting some rubbing on the fan shroud. A 2” spacer would probably be better. I wound up modifying the fan shroud to make it work, but this wouldn’t be necessary if you used a shorter spacer. My Jeep likes to over heat crawling at slow speeds down trails or sitting in traffic. The flex fan excels in those situations. It pulls noticeably more air at idle than the clutch fan did and low speed cooling is no longer an issue. I can’t tell any difference at high speeds, but I never had cooling problems doing 65 mph down the highway anyways. I haven’t noticed any difference in gas mileage either good or bad. It does feel like it has very slightly more power, but I have no way of proving that. For $40 in parts and an hours worth of work I was impressed with the results.

gr8lite said:

OK I replaced everything , now what ? I put in radiator both rad hoses , t-stat , fan clutch , belt, idler , new A-freeze. Still showing on gauge 210! Are these gauges commonly bad? I am pretty p/o'd $250 bucks and no change! Any thought? Thanks to all!

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210 is normal. Remember, the temp sender is in the back of the head, the thermostat is in the front of the engine. They don't correspond to an accuracy of 0.001 degree.

Don't start worrying unless/until you find it going over 225 when stopped at traffic lights or hauling loads upgrade on the interstate.

My 98XJ with 194,xxx miles on it runs rock solid at 210 no matter what I do [knock on wood] but I plan on new hoses, tstat, and maybe a modine 2 row HD, it's getting about that time... will probably do the fan clutch too while I have all the stuff out of the way..