Need help on next steps for overheating prob.

Sorry to beat this dead horse into the ground. I've boiled over for the third time in the last two months and don't know what to try next.

Here's the info:
- outside temp is 90*+ AND
- towing 3,000 lb boat OR
- going up 5%+ grades OR
- slow movement (stop/go traffic or wheelin').

I've installed:
- new 3-row radiator
- flowkooler H2O pump
- 1250 cfm flex a lite electric fan + factory elec fan
- banks header
- poweraid TBS

My engine was scoped and is well sealed and clean (33K miles on it) and no head gasket or exhaust backpressure problems. My winch and off road lights cover about 30% of the radiator. I've considered relocating them, but radiator shop says it shouldn't matter. Tranny doesn't appear to ever get too hot. I have factory tranny cooler and A/C? cooler in front of the radiator (factory configuration). It runs at 210-220* if I'm going over 40 mph.

I'm thinking of (a) engine oil cooler, 2-row radiator w/bigger tubes, high flow catalytic converter (probably not needed), or aluminum radiator. Could it be timing, ignition, air/fuel mixture, ECU settings or some other problem within the engine setup? I'm tired of throwing money and time into this problem. Any help on where to fix next would be appreciated. Thanks.

Mr Planetcat, it's been my experience that anything that blocks the radiator will restrict the airflow and reduce cooling. I would remove the winch and lights temporarily to see if that makes a difference.

It shouldn't matter, but it could. That's why you always want to check something like that...

Also, what coolant mix are you running, and have you tried Water Wetter by Redline? I've used that stuff on problem cases, and it DOES make a difference - $7 well spent. Try keeping forklifts cool sometime, and you'll see what I mean by problem cases...

I'm going to go out on a limb and assume that the fans are both always on? Or what triggers them? Is at least one of them always on? Remember that this system is designed with at least one fan to be running constantly, and not having either fan come on until you start getting warm could be part of the problem as well. If everything else is in good working order and there are a couple inches between the winch and the grille, (and the lights and the grille,) then that should properly matter little.

I see you are registered as being in NorCal - where? I'm in San Jose if you are nearby and would like a second opinion...

5-90

How did you select the capacity of the Flex-a-Lite fan -- and why did you decide to go to that instead of the stock mechanical fan? MOST folks who have tried dual electric fans have been unhappy with the results.

The aftermarket electric fans will usually not draw as much air through the radiator as the OEM setup; however, there are a few folks that are satisfied with them. When I tried an aftermarket electric fan on my van that I use for towing, it was a total disappointment. In this same application I tried the Redline Water Wetter and saw no improvement but it doesn't cost much to give it a try. I agree with a previous poster about the lights being a potential problem. They will definitely hinder airflow to some degree, especially at highway speeds.

Answers to above questions.

Thanks for the input. Here are my answers to your questions:

1. I will try (reluctantly) reloctating the winch solenoid and off road lights to let more air directly hit radiator. This will bum me out, since I like the setup I have now, but will try it.

2. I talked to Redline directly. They are located in Nor Cal. and they didn't do a good job of selling their product based on the description of the problems I gave them. It's worthe the $7 to try it though.

3. I'm running about 70% water, 30% coolant right now.

4. Fans are on a manual toggle. I turn them on when I hit the t-stat setting at around 180*. I installed a 180* robert shaw t-stat, too.

5. I boiled over the first time with the clutch fan. I tested it and it was working correctly (as far as I can tell). It seemed like I could control the flow of air being sucked into the rad better w/electric and the CFM rating of 1250 was pretty impressive. I am considering putting the belt driven fan back in, but w/out a clutch, so it spins all the time. Not sure if that'll help or not.

If the fan clutch is over 3 years old, consider a replacement no matter how good you think it works. Over 5 - replace it anyhow. A quick test fix you can do is to drill it out near the centre and bolt it solid - it can be done with one, but I'd do two for balance. That effectively turns the fan clutch into a spacer.

Even given everything you see on the back of the label, I usually don't run anything other than 50/50 on the coolant. That always seems to help - going with anything else can be a little strange with cooling for some reason.

I think the Water Wetter will help you, as long as your coolant flow is otherwise good.

I also think that having the fans come on from a toggle might be part of the issue - try running about with them on for a while - or turned on once the temperature gage starts to register - and see what that does.

See also your PM.

5-90

I assume you've checked the basics, cap/shroud/t'stat? I've found here in the desert that running to low a t'stat can cause a motor to over heat to. Might try going back to a 195* thermostate. Is it boiling over or are you just judging by the factory gauge?

Keith

I will give you the same advice other on here have.

1) Change out that coolant and get the mix to a coolant/water ratio of 50/50 or 60/40. Coolant transports the heat to the radiator so it can be removed from the system by using the 70% water ratio your coolant can not carry as much heat.

2) You do not say if you have an Aux transmission cooler. If you don't have one that can be the lion share of your problem. The ATF is heating back up the coolant just before it goes into the engine. My owner's manual says if you tow over 2000 lbs you have to have an aux trans cooler.

3) Go to your Jeep dealer and buy a New radiator cap and a new 195 thermostat and install them when you are changing the coolant. My raditor shop told me if you heat the thermostat to 225F one time you can damage it, then it will open late and close late. I went in there to buy a radiator and he told me to get a dealer thermostat and see if that fixed my problem. I did and he loss a radiator sale but solved my problem

4) Remove the aftermarket cooling fan, go buy a new fan clutch, and install the belt driven fan. I have NO confidence in the "tests" to determine if the fan clutch is bad. I am going to change my next year. The hoses and the clutch will be 4 years old at that time, cheap insurance. Also when you need cooling that engine fan may take more power to run but you will get air movement.

You said you did over heat with the mechanical fan installed BUT before that day did the cooling system work fine?

I think the solution is at hand is part of the problem is self inflicted in part but fully recoverable. Get a good fan clutch installed, I got mine at carquest but the replacement will be a AC Delco since it was the OEM part I removed in 2000 after 12 years of service. So new clutch, thermostat, radiator cap and 50/50 coolant and you should be as good as new. Please do not blow off changing the thermostat and radiator cap.

More answers.

Thanks again, all. Here are some more answers:

1. I reduced the coolant mixture from 50/50 to 70/30 water/coolant because I "heard" that water dissipates heat better than coolant. I was on a long road trip and basically started refilling the overflow bottle w/water as the jeep boiled over. I will add more coolant and water wetter.

2. The t-stat is a brand new Robert Shaw 180* installed last week. I boiled over (not just overheated) before it was installed and after.

3. I have the factory aux tranny cooler/towing package. It is sandwiched in front of the engine radiator and the A/C radiator. It seems like the way this is setup that over 50% of my radiator surface area is covered with other radiator-like devices (tranny and A/C). It's the factory setup, but seems like the air is hot by the time it actually hits the radiator.

4. I will try the bolting method of locking the clutch on the clutch fan to get the fan to spin all the time or buy a new clutch fan.

I feel like since it's only overheating under loads or up hills, that maybe the tranny is actually sending heat back into the internal tranny cooler that's inside the radiator (not the aux tranny cooler). Essentially, taking all of the cooling power from the engine coolant part of the radiator? The tranny never gets hot either. Just a thought. Thanks again.

If it was me my first move would be to buy/borrow a known-good clutch fan and put it in like stock (i.e., not always on). Next would be a stock dealer 195 thermostat (does your thermostat have a weep hole - I assume it does, but I had an aftermarket stat without the weep hole once and it did make a difference when I swapped it for stock). Based on what you describe, it seems to me you really shouldn't be having overheating problems with that setup. 33k on the engine and clean passages, new radiator and waterpump, on a 96. The stock cooling setup should work.

Water does cool better than 50/50 mix. I had a bad overheating summer a few years ago and went to straight water and it made a 5-10 degree difference. Straight water is bad for the radiator though.

The winch and lights don't completely block air flow, they merely divert it. So if they're covering 30% of the area in front but have a few inches clearance, the effect on air flow is going to be less than 30%. Still, you need every % right now, so I'd move the lights at least. I've got that same winch, and back in that same bad summer I just left the cover off, winch still on, and that made a difference.

With the new radiator I assume the fins are clean, but you might want to check the condensor and oil cooler to be sure there's not crap stuck in between the fins blocking air flow.

Good luck, this has to be driving you crazy. Again, I don't hear anything that would make me think as tock setup shouldn't work for you, so I'd suggest going all the way back to stock (good conditon, know-working stock parts I mean) and then start over making one change at a time and testing for better/worse. My bet is the problem lies in the fans and maybe thermostat.

I thought of a couple more things. When you changed your radiator did you also install new ratiator hoses or did you notice a spring inside the lower raditor hose which you left installed. You could be having the lower hose suck shut with your new pump.

There have been a lot of experience gained by the people on this board and the group concensus is to use the Mopar 195F thermostat. It the only one out there with the air vent holes pre drilled. Also been lots of discussion about thermostats. Also the engine is designed for operation with a 195 thermostat, you know clearances etc and the engine computer looks for 180F to go into closed loop operation. by running a 180F themostat you may be running rich and decreasing your MPG. It not that I am brand loyal, just passing on painful lessions learned by the rest of us who post. A dealer thermostat around $10, and if it does not change anything you are not out much.

You did not mention the raditor cap, If you have not changed that in the past week then change it also. With a bad cap you will see temperatures rise because the coolant takes less BTUs/lb to raise 1 degree F at atmospheric pressure, but at 13 or 15 psig that BTU/lb value is higher.

I seem to recall a method of detaching the spring on the front of the fan clutch and turning it 90 degrees to "lock it up". I don't know my book right now but that would work as an experiment to prove out if the fan clutch it the problem. I think I'd buy a new clutch, don't barrow a used one since there no good way to test them, and install it. If that fixes the problem then you don't have to pull that fan back off. I just hate working with those 4 nuts that hold it on.

One more thing when you filled the engine did you get all the air out. It a cronic problem with the 4.0. I am not sure if they deleted the coolant temp sensor in the head of your engine but read this like, by pulling the sensor I got all the air out and only had to add a pint after a day or two of driving. http://www.olypen.com/craigh/cooling.htm

I know it driving you nuts but IT WILL get fixed, don't throw any tools at it and mess up the vehicle.

You said you put in a new water pump. Is there a chance you got one that rotates the wrong direction? My 88 XJ uses what they call a "reverse" water pump. If you use the right hand rule and point your fingers in the direction of rotation then your thumb will point toward the engine or toward the radiator. If your thumb points to the engine is a "forward or normal" water pump. If the thumb points to the radiator then it is a reverses. It been a problem people getting the wrong water pump, the impeller designed to turn the other direction. I'd only investigate this AFTER you do the other things we talked about.

Thanks again. Here's what I'll do. . .

Thanks again everyone. Here's what I'm going to try:

- New factory rad cap
- add Watter wetter and get coolant to 50/50 mix
- remove flex a lite electric fan, sell on eBay
- install new clutch fan ($109 from stealership, gulp!)
- remove off road light from front bumper in front of grill
- relocate solenoid from Warn M8000 away from front of grill
- make sure no air in system (use temp sensor method)
- check water pump for reverse rotation (I'm pretty sure it is)
- check lower rad hose to make sure spring is installed to prevent collapsing.
- Replace 180* t-stat w/factory 195*

Addendum: Will consider going to a 2-row bigger tube rad, but not sure if this is overkill.

FYI, the first time my XJ overheated was in May. The cooling system was bone stock and I boiled over going up to the Sierras in 96* weather with just me, one passenger, and fishing gear. If it was my original clutch fan the whole time, then I've chased my tail for 10's of hours on this.

Alright, first of all, I didn't read the whole thread, so I may be repeating people here. I've had one hell've a battle with overheating, been going on (off and on) for about two/three years. I've conqured it, I am no longer afraid of my AC!

Here's my suggestions.

Thermostat: Throw away that 180* one and get a genuine Mopar 195. The Mopar ones are worth the extra money (about twice the cost of an aftermarket I believe). Running a cooler thermostat will not help at all for your overheating on an XJ. All it will do is give you less power and worse gas miliage, noticibly so!

Fans: As has been said, I've seen a few reports of people trying aftermarket fans and ending up going back to the stock configuration. I'd say put a new clutch fan on, if you're worried about the fan get a later model OEM fan (the turbine style).

Radiator!: You say you have a three row. Is it a GDI? My main problem was a clogged GDI radiator. A factory clogged GDI radiator, was clogged with solder from the factory! I'd take it to a radiator shop and ask them to rod it out, if they find it's clogged with solder you'll have to buy a new one, I would suggest a large tube two row, they do work very well (that's what I have).

Coolant Mixture: I always run 50/50 myself, in fact, I prefer to run 50% coolant, 50% distilled water.

Water Wetter: Get it, it works very well. For a testomonial take my old '78 Ford Courier. I ran this with a 2.3l 4 without a thermostat. I dumped one bottle of water wetter in it and it made it run 40* cooler! (Those results aren't typical, it's not gernerally that drastic, but still good)

Anyway, there you go...

Have fun!
Sequoia

check your heater control unit, there is a small hole in the check valve that can get plug, i learned the hard way and changed out all the same stuff you did.......

fan clutch

I took my fan clutch off and rebent the end of the spring so it was about 3/16 in longer, it went from not locking at all to staying locked up in town when ever it is above 60 degrees out. It's a little more noise ,but i have'nt seen the gauge above 210 for a long time. Richard