at the end of my rope with overheating issues.

[RedHeep]

I ran the same efans for three years on a griffin rad (and they worked fantastic (until the rad sprung a leak)-- kept the truck at 190 in the dead of summer, up hill, offroad .... so.....never say never

And you put the same fans on another radiator and now it sucks. It probably wasn't the awesome fans you had.

I played the "it's not the radiator" game for 2 years. Jeep got hot at 60 mph on the highway, when everyone knows that it shouldn't because of airflow. I went through water pumps, thermostats, hoses, fan clutches (zj and xj) until I finally bit the bullet and replaced the CSF radiator that I was convinced wasn't the problem.

Now it works just fine.

 

[jmg222]

I played the "it's not the radiator" game for 2 years. Jeep got hot at 60 mph on the highway, when everyone knows that it shouldn't because of airflow. I went through water pumps, thermostats, hoses, fan clutches (zj and xj) until I finally bit the bullet and replaced the CSF radiator that I was convinced wasn't the problem.

Now it works just fine.

we're talking the same language. see my posts a few posts up. I'm convinced at this point it's the rad. hoping novack stands behind it's product. Can't blame me for trying every other possible thing though -- this rad + shroud + fans cost me almost $800.

 

[Mach2nh]

You dont want to just remove the thermostat and not install a re-stricter. To much flow is a bad thing. The thermostat opens and closes keeping the temp with in a range. Allowing the coolant to pull the heat from the motor and when its up to temp the Thermo will open so it can shed that heat out the rad. But even if the temps are high and the thermo never shuts, its still acting as a re-stricter slowing the flow of coolant so it can pull more heat from the motor.

 

[jmg222]

You dont want to just remove the thermostat and not install a re-stricter. To much flow is a bad thing. The thermostat opens and closes keeping the temp with in a range. Allowing the coolant to pull the heat from the motor and when its up to temp the Thermo will open so it can shed that heat out the rad. But even if the temps are high and the thermo never shuts, its still acting as a re-stricter slowing the flow of coolant so it can pull more heat from the motor.

I pulled it just to see if the thermo was sticking. Makes zero difference with it in or out (just takes longer to overheat, no surprise).

 

[rockclimber]

You dont want to just remove the thermostat and not install a re-stricter. To much flow is a bad thing. The thermostat opens and closes keeping the temp with in a range. Allowing the coolant to pull the heat from the motor and when its up to temp the Thermo will open so it can shed that heat out the rad. But even if the temps are high and the thermo never shuts, its still acting as a re-stricter slowing the flow of coolant so it can pull more heat from the motor.

false.

basic fluid dynamics. there is no such thing as too much flow in a closed loop system. in fact, the more flow, the better it will cool. you could theoretically overcool, but if he is overheating already there is little chance of that.

 

[blondejoncherokee]

Did you check your timing ? Is it running lean at all? I e heard bad things about all Efans . Maybe try a mech fan and or higher output e fans

 

[Rod Knee]

This.

Ditching my triple elec fans and going back to a mech and aux fan setup was the best thing ever for my cooling system.

Installing electric fans always seemed to me like something that people with too much time on their hands did.

 

[jmg222]

Installing electric fans always seemed to me like something that people with too much time on their hands did.

except when there's no room for a mechanical fan... which there isn't, in my engine bay. Which is why I'm using e-fans. But appreciate the thought.

 

[Rod Knee]

The thermostat opens and closes keeping the temp with in a range.

Actually, the thermostat's function is simply to keep the coolant in the engine block above a certain temp by staying closed until the engine, upon startup, reaches that specific temp. When it reaches the specific temp it shuts in order to keep the coolant warm. It is the cooling system as a whole that keeps the coolant in the engine within a range.

In Yuma, Arizona you can get by without a thermostat. In Yankton, South Dakota you need it.

 

[RedHeep]

Actually, the thermostat's function is simply to keep the coolant in the engine block above a certain temp by staying closed until the engine, upon startup, reaches that specific temp. When it reaches the specific temp it shuts in order to keep the coolant warm. It is the cooling system as a whole that keeps the coolant in the engine within a range.

In Yuma, Arizona you can get by without a thermostat. In Yankton, South Dakota you need it.

It's also designed to ensure that the engine operating temperature meets the viscosity specification of the oil that is in the engine. Too cold and it doesn't lubricate properly, too hot and it doesn't lubricate properly either. That's why there are multiple viscosity oils and their intended use based on the manufacturer's specification for operating temperature.

You need one in Yuma just as much as you need one in Yankton.

The issue here probably isn't the fans. He said it's running hot on the highway, where no fan will pull the air that the jeep provides by going 60 mph. It's a not enough radiator issue. When that's fixed, the fans will do the job they did before the radiator change.

 

[Rod Knee]

It's also designed to ensure that the engine operating temperature meets the viscosity specification of the oil that is in the engine. Too cold and it doesn't lubricate properly, too hot and it doesn't lubricate properly either. That's why there are multiple viscosity oils and their intended use based on the manufacturer's specification for operating temperature.

You need one in Yuma just as much as you need one in Yankton.

The issue here probably isn't the fans. He said it's running hot on the highway, where no fan will pull the air that the jeep provides by going 60 mph. It's a not enough radiator issue. When that's fixed, the fans will do the job they did before the radiator change.

Thanks.

 

[jmg222]

let me throw one thing out-- could the fans possibly be interfering with airflow at highway speeds?
The way this rad is constructed, the three fans are mounted on the face of the rad--- the shroud is a metal covering the areas between the fans, with flaps on rubber grommets that open up at speed.

The fans turn on at 190 degrees. In my old application, without the metal shroud, this wasn't an issue, becuase other than the fans mounted very close to the rad, there was a ton of airflow. With this new rad, if I'm going at highway speeds, and the fans kick on, won't the fans interfere with airflow? in other words, if the air speed coming in at highway speeds is 55 mph, and the fans are only capable of drawing air in at (whatever) 20 mph, I'm thinking this may interfere with airflow at high speeds-- the only flow through the rad at highway speed when the fans are on would be through the little flaps.
I'm debating putting a relay and a switch on the fans and try turning the fans off on the highway, see if that does anything... but before I bother,m would love to get input.

By the way, this is the rad I'm using -- 2 row aluminum novak-- specifically designed for a 350 conversion in the xj:

http://www.novak-adapt.com/catalog/cooling/radiators/xj/k-xj31h.htm

this is the shroud (listed near the bottom, fx3400):

http://www.novak-adapt.com/catalog/cooling/radiators/xj/k-xj31h.htm


Novack installed the fans and shroud and shipped as a unit, this is it installed:

 

[techno1154]

I have been following this thread faithfully. I love the debate as to the usefulness of electric fans verses mechanical fans. I will not take part in that debate since I ditched the OEM mechanical fan for dual electric fans which have worked well for me but also exposed some things which would not have been so had I kept the OEM setup.

I just looked at the Novak web site at the fans you listed as those you are using. The one thing I look for when sizing the fans I have been using since 2004 is the static CFM. Fan depth front to back is also important in the XJ's. That one important information seem to be missing from the web site. It is nice to have multiple fans but how much air do they actually move?

The other thing that is perplexing in the fact that your XJ over heat at highway speed. On my XJ, the fans do not come on at highway speed unless I am using the air con' or maintaining speeds in the excess of 80 MPH at which point they cycle on and off.

 

[Digger87xj]

Do you still have the Griffin? I'm curious how many fins per inch (FPI) it has.

The first one Novack built for me had 12 FPI. It would run 235-240 in simple traffic, fans on high w/ ambient temp at 80*F.
After I called them they said they were having problems with the 'new' design and were in the process of finding someone else to source the cores from. 6 months later they sent me my current one, no charge.
This one I have now is 16 FPI. Now the engine stays between 196-206 as the fans cycle on and off using only low speed.

I'm convinced if I can find an 18 or even better, a 20 FPI radiator my cooling issues would be non-existent.

 

[jmg222]

I have been following this thread faithfully. I love the debate as to the usefulness of electric fans verses mechanical fans. I will not take part in that debate since I ditched the OEM mechanical fan for dual electric fans which have worked well for me but also exposed some things which would not have been so had I kept the OEM setup.

I just looked at the Novak web site at the fans you listed as those you are using. The one thing I look for when sizing the fans I have been using since 2004 is the static CFM. Fan depth front to back is also important in the XJ's. That one important information seem to be missing from the web site. It is nice to have multiple fans but how much air do they actually move?

The other thing that is perplexing in the fact that your XJ over heat at highway speed. On my XJ, the fans do not come on at highway speed unless I am using the air con' or maintaining speeds in the excess of 80 MPH at which point they cycle on and off.

I had the same question, and looked the fans up online. Here they are :
http://www.spalautomotive.com/eng/products/view_axial.aspx?id=VA07-AP12_C-58A

As for the fan's coming on at highway speed, scroll up a few posts (the one with the pictures). I'm slowly convincing myself that the shroud just isn't designed properly, and that it should be a more open design. I hit highway speeds, the temp just hits 190, the fans click on, then because they're on at highway speed, they impede airflow... and the temps continue to rise.

another solution I'm thinking is putting in a hotter temp sensor on the fans.. maybe 200? I mean, if I'm on the highway at 55, my coolant temp should be in the 190s with the fans completely off. My gut is telling me that the combination of the fans coming on at highway speeds combined with the closed shroud is just killing airflow.

as for the mechnical vs. e-fan, it's really just an old-timer vs. current gen thing I think. There's absolutely nothing inherent in a *well-designed* e-fan that would prevent it from being just as good and in some applications better than mechanical. I also think that since they're so much easier to make, there's a ton of ebay crap out there that give people bad experiences. Like anything else, you get what you pay for.

 

[jmg222]

spoke to novak-- gotta say, even though this is a pain in my rear, they're great to deal with. They want me to try higher capacity fans first (which they're sending me). I highly doubt those will work, but I'll try anything -- if that doesn't work, they'll either send me a new rad and space the shroud back a bit, or I'll send mine in for them to rework.

 

[techno1154]

spoke to novak-- gotta say, even though this is a pain in my rear, they're great to deal with. They want me to try higher capacity fans first (which they're sending me). I highly doubt those will work, but I'll try anything -- if that doesn't work, they'll either send me a new rad and space the shroud back a bit, or I'll send mine in for them to rework.

It is good the vendor is working with you. I hope problem is resolved soon so you could enjoy the XJ.

This is the fan setup on my XJ. It is not a drop in unit. They had to be custom fitted but it get the job done. They are also power hunger requiring a higher out put alternator. I installed a copper/brass radiator at the same time.
http://http://www.summitracing.com/parts/der-16928

 

[Digger87xj]

Just wanted to throw out my experience....

I too called Novak this past Monday and talked with them. He listened to what I had to say, took my number and told me he'd call back.

He called me back today (Friday) and told me that they were going to build me a new radiator. No charge, and pay return shipping for my now 2 year old one.

They have had another redesign since shipping mine.

I am ecstatic!

 

[iluv83vettes]

You get what you pay for?

 

[jmg222]

well, to close the loop on this-- I spent an hour or so trouble shooting the issue w/ novak over the phone. They agreed that the rad was the culprit, and that the shroud was sitting too close to the cooling fins. I gave them measurements for clearance between the front of the motor and the fans on the rad, and they redesigned the rad so that the shroud was sitting about 1/4 inch or so off the cooling fins. they sent me the newly-redesigned rad, along with three all new spal fans -- 2 are double the cfms as the old ones, the third is a few hundred better (the third sits in the center of the rad, and due to clearance issues had to be shallower than the other two). AND, to boot, they second-day aired the rad at no charge because I told them I wanted to get it installed last weekend.


Anyway, I installed everything last weekend, and it stays ice cold-- in the driveway in the sun at 90degrees outside idling with the a/c on, the motor actually cools down enough that the temp drops below the 180 trigger temp for the fans. No more issues on the highway -- even with the winch and license plate reinstalled, coolant never goes above 190.
Anyway, kudos to novak. Really stand-up vendor. The rad/shroud/fan setup I bought from them was worth every cent I paid for it -- if you're doing a 350 conversion, I can't recommend these guys enough.