overheating (Kinda long)

[Dingo509]

Is the new aftermarket water pump the correct (reverse) rotation?

Is the volume of water bypassing the radiator through the heater valve excessive (do you have a flow restrictor in the valve or heater core bypass hose)?

Is the air dam and shroud under the radiator support in place?

The water pump is correct rotation i verified with a buddy's 95 since he had his water pump out at the same time. the new is an airtex btw.

I don't know if there is a restrictor in the heater circuit or not. all four hoses and the valve are new mopar parts.

The air dam and shroud under the radiator where removed probably 6 yrs ago. about 3 years before the problem started.

dingo

 

[Ed A. Stevens]

I don't know if there is a restrictor in the heater circuit or not. all four hoses and the valve are new mopar parts.
dingo

The heater valve may be full port (5/8 unrestricted flow) on both the heater circuit and the bypass circuit. If the bypass is full port the coolant diverted around the radiator will impact the cooling (but usually not as much as you report).

Are you still running the dual electric fans?

 

[Dingo509]

The heater valve may be full port (5/8 unrestricted flow) on both the heater circuit and the bypass circuit. If the bypass is full port the coolant diverted around the radiator will impact the cooling (but usually not as much as you report).

Are you still running the dual electric fans?

At the moment yes i am running the dual electrics. I am planning on putting the mech fan back on as soon as i find a stock shroud, lost the original.

I thought about trying to run the heater hoses directly to the heater core and then put a block off style valve in instead of the bypass. I think dodge FS vans around late 80's early 90's used a valve like this that was vacuum operated. The main thing i was worried about was the posibility of cavitaion at the water pumpfrom the lack of collant flow.

I also thought about using a large trans cooler as sort of an aux. radiator on the heater return line before it went back to the water pump. Whenever i get my OB shower done the heat exchanger will fit into the right fender and will run after the heater so that might help cool that part of the system plus add more coolant. Outside of exchanger is 3"dia x 24" long copper pipe. But that's a whole 'nother story.

Dingo
Ancient XJtribe cooling dance failed too
Starting voodoo next week

 

[Ed A. Stevens]

At the moment yes i am running the dual electrics. I am planning on putting the mech fan back on as soon as i find a stock shroud, lost the original.

Dingo
Ancient XJtribe cooling dance failed too
Starting voodoo next week

I expect the return to a mechanical drive primary cooling fan and shroud will solve the problem. The increased pressure under the vehicle, and behind the radiator, at speed is reducing the air pressure difference across the radiator core that promotes airflow. This is (one reason) why it works at idle and slow speeds, but overheats at highway speed.

Few have proven a reliable electric fan conversion to be successful. The power draw of some of the new fans (Taurus and Benz fans) can overcome the increase in pressure that builds under the XJ at speed but they are not small enough to fit. Few aftermarket fan blades and motors are designed to pull the 40+ amps that are needed to power the significant airflow and pressure drop required. They flow great with low amp draw with minimal external static pressure on the exhaust side of the blades, but quickly lose airflow if they encounter any pressure resistance.

Good Luck.

 

[Gojeep]

This does not make sense to me at all. There should not even be a need for a fan of any type at speed. There is another problem here some where. I first thought cavitation but that would happen at slow speed too with high revs. What does bother me is how much of the frontal area is blocked with lights or winch? Is the problem that the air is backing up due to extra battery or other gear added under the hood? Have you tried just spacing up the back of the hood an inch to see if this improves the airflow?

 

[rsalemi]

One other thought - leaking head gasket - Get a radiator shop to pressure test the system - a compression leak into the coolant holes will cause overheating.
And I second Ed's thoughts on the mechanical fan - I solved an overheating problem on my 4.0 by replacing the fan clutch with a HD one from Summit Racing - sounds like an airplane but cools the motor!!!

 

[Bradlybob]

I'm currently running a flex-a-lite 110 fan set up too and have had no resolution to the o'heating problem. I have tried everything except going back to the stock fan and using a Modine rad. By the way mine acts the same as yours, o'heats on flat freeway even. I was kind of wondering about the A/C condenser restricting airflow through the rad. It's clean on the surface, no bugs/mud, but I can barely see through it. The fins on the surface are straight but deeper inside core they seem to be kind of twisted, not like a rad where you can see straight through when viewed at the correct angle. I replaced the air dam and that didn't help either. I'm about ready to buy a YJ!

 

[Dingo509]

This does not make sense to me at all. There should not even be a need for a fan of any type at speed. There is another problem here some where. I first thought cavitation but that would happen at slow speed too with high revs. What does bother me is how much of the frontal area is blocked with lights or winch? Is the problem that the air is backing up due to extra battery or other gear added under the hood? Have you tried just spacing up the back of the hood an inch to see if this improves the airflow?

on the front i have a custom 4x4 front bumper w/grill guard warn xd9000i with soft cover and 3 hella 500's (i'd post a pic but i don't know how) BUT all this was on before the problem started. inside the battery is gone and there's a york in it's place. The only thing about blocking airflow is that id doesn't overheat just on the hiway, it also does it at 15 and up pulling a steep hill.

I have holes cut in the hood now will spacing the hood help more if you think it will i'll try it.

Dingo

 

[Dingo509]

One other thought - leaking head gasket - Get a radiator shop to pressure test the system - a compression leak into the coolant holes will cause overheating.
And I second Ed's thoughts on the mechanical fan - I solved an overheating problem on my 4.0 by replacing the fan clutch with a HD one from Summit Racing - sounds like an airplane but cools the motor!!!

Im going to swap back to the clutch fan as soon as i find a shroud. would you guys recommend the clutch or just a spacer?

I tried the head gasket, checked the block .001 warp, within spec. the head was .007 max twist is .006, had the head machined .008. No change.

Dingo

 

[Dingo509]

I'm currently running a flex-a-lite 110 fan set up too and have had no resolution to the o'heating problem. I have tried everything except going back to the stock fan and using a Modine rad. By the way mine acts the same as yours, o'heats on flat freeway even. I was kind of wondering about the A/C condenser restricting airflow through the rad. It's clean on the surface, no bugs/mud, but I can barely see through it. The fins on the surface are straight but deeper inside core they seem to be kind of twisted, not like a rad where you can see straight through when viewed at the correct angle. I replaced the air dam and that didn't help either. I'm about ready to buy a YJ!

What else have you tried? maybe between us we can t
fix theses things once and for all.

Dingo

 

[wsuxjer]

Brian, do you still have the stock block in there? Stock cam, etc?

 

[Dingo509]

Brian, do you still have the stock block in there? Stock cam, etc?

Yeah the internals are all stock, the intake and exhaust are all upgraded.

Did you ever work at Camp Fife?

Dingo

 

[CRASH]

This does not make sense to me at all. There should not even be a need for a fan of any type at speed. There is another problem here some where. I first thought cavitation but that would happen at slow speed too with high revs. What does bother me is how much of the frontal area is blocked with lights or winch? Is the problem that the air is backing up due to extra battery or other gear added under the hood? Have you tried just spacing up the back of the hood an inch to see if this improves the airflow?

To the contrary, if I unplug my electric aux. fan, I run 15 degrees warmer on the freeway. Fans perform a service at highway speeds as well as slow speed situations.

Dingo, get that mech. fan in there and report back.

CRASH

 

[FUNKYTEE5]

One other thought - leaking head gasket - Get a radiator shop to pressure test the system - a compression leak into the coolant holes will cause overheating.
And I second Ed's thoughts on the mechanical fan - I solved an overheating problem on my 4.0 by replacing the fan clutch with a HD one from Summit Racing - sounds like an airplane but cools the motor!!!

Ditto on the leaking head gasket. It sounds like the motor has gotten hot quite a few times? I just dealt with the notorious 2.5 liter Subaru head gasket problem. Only had symptoms after 20 miles or so, or pulling up a grade, then it'd boil over. You can have a shop do a hydrocarbon test in the coolant to rule out a leaking head gasket. I suspected everything but the head gasket on that one! It'd be best to get it done while symptoms are present. Many times these leaks will only open up after being warmed or under load. Also, have you tried running with the t-stat out? Does it still boil over? Good Luck

FUNKYTEE5

 

[wsuxjer]

Yeah the internals are all stock, the intake and exhaust are all upgraded.

Did you ever work at Camp Fife?

Dingo

Yup.

I would think the problem lies somewhere else other than your cooling system. Try putting the mechanical fan back in like Crash said, and check the head gasket and pressure test the cooling system like others said.

 

[Gojeep]

I will say it again, dont run the flexy-lite 110. They are shocking at cooling and will even lose fins later on!
Running three lights across the front it is not helping at all either. I have two electric fans and they have never come on at highway speeds no matter how hot it is including over 100 degrees while towing in the Outback. If your fans come on you have an inadequate radiator or water pump. Thats why there is more than a fan problem here as well.

 

[Dingo509]

I will say it again, dont run the flexy-lite 110. They are shocking at cooling and will even lose fins later on!
Running three lights across the front it is not helping at all either. I have two electric fans and they have never come on at highway speeds no matter how hot it is including over 100 degrees while towing in the Outback. If your fans come on you have an inadequate radiator or water pump. Thats why there is more than a fan problem here as well.

you're right about the damn fans losing blades i just lost blades on one again today so now i'm down to only one fan. As far as the lights i've taken the whole grill guard off and it didn't change anything. the fans are always on because i've rewired them to a switch in the overhead console.

So this is my next plan of attack
1. leave one fex-a-lite 110 in place of the stock electric (i will replace this later with a stock 95-up fan) and reinstall the original fan with a spacer.
2. Replace the temp sensor for the computer and the Air temp sensor
3.Replace the GDI radiator with an aluminum from alumrad.com this has 1 3/8 single tube.

If that doesn't work then i will put of the coilover project and by the $1000
Be Cool kit that includeds the radiator and fans.

Then If that doesn't work Buy a 97+ and spend the next year swapping parts.

If THAT doesn't work burn down everthing and buy a honda Or shoot myself in the head (same result in the end)

What do you think?
Dingo

 

[Bob Langford]

How about the thermal viscous fan drive ? I didn't see it mentioned as one of the things replaced in the first post on this thread. I could spin mine easily with the engine cut off, but there was some thick fluid oozing out of the clockspring-like mechanism on the front. So, I swapped it out. Made all the difference. My 96 XJ behaved exactly as you described above: ok when idling, but when under load, temp would climb. For a long time, I ran the aux fan anytime I saw the temp creep up (I wired to a switch inside the cab where I could apply 12v to it).

 

[hotrod76car]

I was woundering if you fixed your overheating prob yet. I had the same one and put the aluminum rad in and fixed mine

 

[Dingo509]

I was woundering if you fixed your overheating prob yet. I had the same one and put the aluminum rad in and fixed mine

as of right now, the XJ sits apart in the driveway for more upgrades/repairs. 4 link longarm setup, new trackbar, onboard shower, and fix the rear ARB.

I just ordered the Visteon aluminum core radiator from radiatorworld.com for $116. this is the same (by spec) radiator as the have listed on Alumrad.com
i have also ordered the 14" Zirgo electric fan, as the mechanical fan does not fit well with the york compressor. I have also relocated the transcooler lines so they don't go thru the radiator anymore. I will post an update when i get this thing back on the road.

Dingo