HD cooling system

[02libby]

What is the purpose of 2 fans? It doesn’t seem like there are many Liberty’s that have this system. Can I delete the mechanical fan and keep the electric?

 

[Big Al]

I was kind of thinking of doing the same thing in the winter.
Just using the electric fan as my heating system in the cab is running a bit cool. I haven't seen my electric fan come on yet.
Only had my KJ for 5 months.

 

[02libby]

I just don’t want to delete it and it be detrimental to the cooling. I am currently installing a new radiator and water pump. I had an overheating issue. Started by replacing the thermostat. Pump was making noise and I found a leak in the radiator tearing things down.

 

[duderz7]

You were having an overheating issue and that's led you to consider remova fan? fan?

 

[LibertyTC]

Hopefully you purchased a Mopar rad & Mopar thermostat.
When you realize how hot the Jeep can get in summer....
Suddenly the heavy duty cooling package/ viscous fan becomes a complete advantage, over many that have to simply rely on the electric fan alone.
I wish I had the HD cooling...

 

[02libby]

Hopefully you purchased a Mopar rad & Mopar thermostat.
When you realize how hot the Jeep can get in summer....
Suddenly the heavy duty cooling package/ viscous fan becomes a complete advantage, over many that have to simply rely on the electric fan alone.
I wish I had the HD cooling...

Yes I purchased the Mopar thermostat after reading about issues of other brands. That obviously wasn’t the issue. Shortly after I started getting a screeching sound from the water pump on cold mornings so started looking at that when I noticed a crack on the plastic tank of the radiator. I just wasn’t sure if the HD cooling was beneficial.

 

[JeepJeepster]

I cant recall 100%, but did the HD cooling option come with a single speed electric fan? I recall reading that you couldnt just add a mechanical fan b/c that option came with a different electric fan. I did just add the mechanical fan to my 04 but it already had the bigger fan shroud that, for unknown reasons, the 2004's came with. Mine had a 2 speed electric fan from the factory. A member that doesnt seem to be around anymore always said the mechanical fan didnt kick in till (dont quote me on this) 230F, so I would think the electric fan that came with the HD cooling option would be able to handle 100% of the cooling.

Ive been thinking about removing the mechanical fan for the winter just to see if my mpg improves any. I unknowingly bought the HD fan clutch and that thing roars like mad anytime you stop and for the first ~mile of driving.

Just an FYI, you can overheat in the winter if the electric fan goes bad and the 3.7 is not known for handling overheating very well... This was the biggest reason I went with the mechanical fan. And the fact that the electric fan didnt kick on till 217F, I didnt like the temp constantly going from 195F to 217F then back to 195F.

Also an FYI, cooling fans have nothing to do with heat on the interior of the vehicle. Its always perplexed me when I see card board in front of radiators in the winter....

And to answer the purpose of having two fans, its for heavy duty cooling...

 

[duderz7]

The cardboard helps a vehicle warm up faster, and stay warmer when driving in cold. Matters more on older vehicles with big open frills and huge radiators.

 

[02libby]

I cant recall 100%, but did the HD cooling option come with a single speed electric fan? I recall reading that you couldnt just add a mechanical fan b/c that option came with a different electric fan. I did just add the mechanical fan to my 04 but it already had the bigger fan shroud that, for unknown reasons, the 2004's came with. Mine had a 2 speed electric fan from the factory. A member that doesnt seem to be around anymore always said the mechanical fan didnt kick in till (dont quote me on this) 230F, so I would think the electric fan that came with the HD cooling option would be able to handle 100% of the cooling.

Ive been thinking about removing the mechanical fan for the winter just to see if my mpg improves any. I unknowingly bought the HD fan clutch and that thing roars like mad anytime you stop and for the first ~mile of driving.

Just an FYI, you can overheat in the winter if the electric fan goes bad and the 3.7 is not known for handling overheating very well... This was the biggest reason I went with the mechanical fan. And the fact that the electric fan didnt kick on till 217F, I didnt like the temp constantly going from 195F to 217F then back to 195F.

Also an FYI, cooling fans have nothing to do with heat on the interior of the vehicle. Its always perplexed me when I see card board in front of radiators in the winter....

And to answer the purpose of having two fans, its for heavy duty cooling...

I believe you’re right about the mechanical fan coming on at 230. The electric is a single speed and I see this one on mostly during summer months. Can’t really say I have noticed the mechanical one on until the over heating issue happened. I was curious about a MPG gain too if I delete it. I have until this Wednesday to decide if I will delete the mechanical fan. That’s when the new radiator comes in. I tested the thermostat in boiling water to make sure it was opening and it was. And I flushed the block out. Hopefully this fixes the issue.

 

[JeepJeepster]

The cardboard helps a vehicle warm up faster, and stay warmer when driving in cold. Matters more on older vehicles with big open frills and huge radiators.

If the vehicle has a properly working thermostat then you shouldn't need to block the radiator.

I believe you’re right about the mechanical fan coming on at 230. The electric is a single speed and I see this one on mostly during summer months. Can’t really say I have noticed the mechanical one on until the over heating issue happened. I was curious about a MPG gain too if I delete it. I have until this Wednesday to decide if I will delete the mechanical fan. That’s when the new radiator comes in. I tested the thermostat in boiling water to make sure it was opening and it was. And I flushed the block out. Hopefully this fixes the issue.

With the original fan clutch not engaging till 230F, I imagine you wont really see any mpg gains by removing it. And I wouldnt trust the single speed fan either. I would need to see the CFM ratings for the two speed fan and single speed fan before removing the mechanical fan.

 

[tommudd]

You are not going to gain much at all or anything removing the HD cooling fan
Makes as much sense as some removing skid plates when going on a trip to get better mileage
While you may gain a 1/10 or so MPG, your time spend removing and replacing is worth a whole lot more

 

[02libby]

You are not going to gain much at all or anything removing the HD cooling fan
Makes as much sense as some removing skid plates when going on a trip to get better mileage
While you may gain a 1/10 or so MPG, your time spend removing and replacing is worth a whole lot more

You guys are right and I agree. With the mechanical fan not turning on until 230 I wouldn’t see or notice any gains MPG. I will keep the 2 fan set up. New radiator arrives tomorrow. I will post back if it fixed the heating issue. Thanks for everyone’s input

 

[02libby]

You guys are right and I agree. With the mechanical fan not turning on until 230 I wouldn’t see or notice any gains MPG. I will keep the 2 fan set up. New radiator arrives tomorrow. I will post back if it fixed the heating issue. Thanks for everyone’s input

Hey guys. Got the new radiator installed with new water pump, belt tensioner, belt and thermostat. Running cool again. But I wanted to clarify from previous. In the HD setup, the mechanical fan comes on at operating temp and stays on. The electric fan only comes on when the ac pump comes on. So possibly could gain a couple of MPG’s if switched out the mechanical. Maybe a project for later.

 

[JeepJeepster]

Electric should also come one around 217F, well before the mechanical fan kicks in. My electric fan also kicks on and stays on till I shut the Jeep off when the transmission gets hot, although I've never been able to find this in writing anywhere....

 

[65Corvair]

Hopefully you purchased a Mopar rad & Mopar thermostat.
When you realize how hot the Jeep can get in summer....
Suddenly the heavy duty cooling package/ viscous fan becomes a complete advantage, over many that have to simply rely on the electric fan alone.
I wish I had the HD cooling...

If you want to upgrade to the HD cooling, you just would need to swap the electric fan and add a mechanical fan.
If I remember correctly 02-04 have the single speed fan, 2 wires at the electric connector. 05-07 have a multi speed fan with 3 wires at the connector.

 

[LibertyTC]

It may have been 02 & 03's that had the single speed. My 2004 has a 2 speed fan, I guess I got lucky !
It does the job ok until you are in 90+F & off road, going slow. Then had had to stop lift the hood in neutral, to let it cool back down.
Hood louvers /ventilation would definitely help!

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The H/D cooling pack did require viscous mechanical fan, new shroud & new electrical fan.

 

[02libby]

Electric should also come one around 217F, well before the mechanical fan kicks in. My electric fan also kicks on and stays on till I shut the Jeep off when the transmission gets hot, although I've never been able to find this in writing anywhere....

I have been watching it all day and I keep getting the same thing. Mechanical fan and electric fan are off, temp goes 1/4 way up the gage, mechanical comes on. Electric stays off, even at 1/2 way up. When I turn the ac on the electric fan turns on, turn off the ac the electric fan goes for about another minute then shuts off but the mechanical fan goes the entire time. My electric fan only has 2 wires so single speed.

 

[JeepJeepster]

Hmm, I didnt know 02-03 had a single speed fan, my 04 is 2 speed. Liberty TC, you can buy the clutch and fan blades since your 04 had the bigger shroud. Fairly easy to install. Did your engine overheat? My transmission has seen 250F but my engine has never went over 217F.

02libby, what do you mean the mechanical fan 'goes the entire time?' It will always spin, it does not stop. The clutch cannot 100% disengage, only partially. Once the viscous fluid heats up, it will then engage the mechanical fan and it will start roaring... It also never 100% engages, it will always slip.

You would need to hook something up to watch the actual engine temp. The temp gauge is sortve an idiot gauge, it will be in certain locations given a wide temp window for the engine. Since its winter, I would say the mechanical fan is moving enough air to keep the engine under the set point to kick the electric fan on. Its also possible someone has replaced your fan clutch at some point so its a little more aggressive.

 

[Big Al]

Also, you can adjust your clutch engagement on your mechanical fan.
There is a bimetallic spring and you can set it so it reaches its full operation sooner or you can dial it back so it take longer to reach full operation.
What you doing is opening the control valve sooner allowing the viscous oil to drive the fan blades or retarding it so it takes longer and hotter temperatures to open the valve.
It operates similar to you torque converter on you automatic transmission.
Each mark on the adjustment will change the valve setting by 10 F.

 

[02libby]

Thanks for all of the input every one. For now it is running great and not over heating anymore. I will keep my eye on everything and let you know how it goes.