Should you get a heavy duty fan clutch?

[Zorba]

It's not keeping the engine cooler by running when it's not needed, such as when it's not even hot enough to open the thermostat.

That much is true - but its still running cooler. Remember, the coolant temperature is HOTTER than the T-stat rating. Instead of shooting right up to the usual "slightly over 210 mark", it takes a VERY long time to get from "somewhat under the 210 mark (where the T-stat opens) to slightly above - and it often never gets there. That tells me that the engine is running closer to the actual T-stat temp, and the radiator is losing more heat thanx to the fan clutch. It also tells me that the radiator could be a bit bigger as well.

 

[MikeE024]

That much is true - but its still running cooler. Remember, the coolant temperature is HOTTER than the T-stat rating. Instead of shooting right up to the usual "slightly over 210 mark", it takes a VERY long time to get from "somewhat under the 210 mark (where the T-stat opens) to slightly above - and it often never gets there. That tells me that the engine is running closer to the actual T-stat temp, and the radiator is losing more heat thanx to the fan clutch. It also tells me that the radiator could be a bit bigger as well.

Fwiw, I noticed that the lesser amount of airflow hitting the cold engine helped the engine get up to temp faster in the cold weather early this morning.

I’ve been paying attention to how long it takes to warm up all winter when idling before driving it to start my day (digital gauge is in my face on the A-Pilar).

That said the lighter fan and Mopar fan were closer in comparison than how long it took the engine to warm up with no fan...which was alarmingly quick with no fan, but the thermostat opened and ETCs cycled as normal for my brief drive going 15-35 mph so no overheat issues.

 

[MikeE024]

Also, I noticed that my IATs were more normal in easy driving a few minutes ago compared to the temps when easy driving after romping around this morning.

I’ll keep my eye on things during my trip this week. Will report back if I find anything worth noting. (As it could relate to coolers in the grill doing their jobs better or the AC working better….we’ll see what happens).

I’ll stick with the USMW model if it does the job…which would also need further testing when I’m daily driving and trailing/crawling in 110-118* ambient temps.

Thanks for all the input guys.

 

[MikeE024]

@freedom_in_4low

Here is a video of the clutch play that I captured around 3 am after my test drive.

As previously mentioned, the play was not there today after the vehicle had been sitting. My gut says to change it just to be safe...unless it's like this for other folks' clutches after being driven around.

 

[freedom_in_4low]

That much is true - but its still running cooler. Remember, the coolant temperature is HOTTER than the T-stat rating. Instead of shooting right up to the usual "slightly over 210 mark", it takes a VERY long time to get from "somewhat under the 210 mark (where the T-stat opens) to slightly above - and it often never gets there. That tells me that the engine is running closer to the actual T-stat temp, and the radiator is losing more heat thanx to the fan clutch. It also tells me that the radiator could be a bit bigger as well.

Refresh my memory...cooler than what? Was the previous clutch defective?

I've had Mopar (OE, not the current version), 2 different Hayden's and a USMW and none of them made any remotely discernible difference in max operating temps, only in fan noise. I can't rule out that midrange conditions might have related to slightly lower ECTs, but those aren't the conditions I'm concerned with. h The difference that will arise from the seemingly lower engagement temperature of the Haydens is only going to be in temperatures that aren't near the limits of the system... I don't really care whether I'm putting around town at 195 vs 205, I care that I'm not getting past 225 when I'm idling (and either fan clutch would be engaged) or cruising down the highway (when neither clutch would be engaged).

You run what you want to run, I'm not trying to talk anyone into throwing their newish fan clutch in the garbage to buy the one I use, I just want to make sure future readers have a good understanding and realistic expectations regarding what a fan clutch can do.

 

[freedom_in_4low]

@freedom_in_4low

Here is a video of the clutch play that I captured around 3 am after my test drive.

As previously mentioned, the play was not there today after the vehicle had been sitting. My gut says to change it just to be safe...unless it's like this for other folks' clutches after being driven around.

interesting...I can definitely see why that would be concerning. Mine definitely did nothing like that when cold but I'll give it a look next time I have it warmed up.

 

[Zorba]

Refresh my memory...cooler than what? Was the previous clutch defective?

Again - it didn't lower the max temperature, but it VASTLY slowed down getting there. Many times, it never hits the "slightly above the 210 mark" like it did before - but when it does, it takes a lot longer to get that hot.

Previous clutch was apparently defective as "suddenly" I was boiling coolant in the puke bottle at hot shutdown, which doesn't happen anymore, thank Goddess.

Now its entirely possible that the thing was defective when I bought the Jeep in 2020, and just kept getting worse. Another anecdote is that I haven't had a heat soak issue since I put the new one in either - the additional airflow is keeping things cooler perhaps?

 

[MikeE024]

Again - it didn't lower the max temperature, but it VASTLY slowed down getting there. Many times, it never hits the "slightly above the 210 mark" like it did before - but when it does, it takes a lot longer to get that hot.

I can only speak to how fast I’ve seen it take to reach 195*, and all has been good for me once it’s gotten to the point. No overheat issues.

But a clutch with a higher duty cycle or one that comes on earlier or is engaged more in lower RPMs “could” help cool other grill mounted heat exchanger items…or the AC condenser (all tbd). I don’t see a difference in the ECTs once the thermostat starts cycling.

I put a piece of paper over the setrab cooler and it sucked against the cooler with the USMW clutch installed…I’ll do a cfm check after my trip.

Previous clutch was apparently defective as "suddenly" I was boiling coolant in the puke bottle at hot shutdown, which doesn't happen anymore, thank Goddess.

My rig’s PO sold me the rig with the e-fan intermittently not working and it boiled over at 260* the first time I drove it (happened when it was in the stall at the AZ emissions station). PO also had a 205* or 210* thermostat installed

Glad u are good again!

Now it’s entirely possible that the thing was defective when I bought the Jeep in 2020, and just kept getting worse. Another anecdote is that I haven't had a heat soak issue since I put the new one in either - the additional airflow is keeping things cooler perhaps?

Very possible that the rest of the system couldn’t handle it being defective and/or it became more apparent when in warmer ambient temps. I had so many issues that I just gutted the whole thing and went mopar. Lucky me with the locked mopar clutch lol.

Our engines are so quiet without the fan turning it’s like riding around in a different vehicle.

 

[MikeE024]

Didn’t like how hot the rig was on the drive to phx. ETCs hit 230 and that didn’t happen when I drove to Vegas, then to and from Moab, or when pulling a uhaul for 7 hours back from Vegas. My IATs and transmission temps were about 10-20* higher than I’m used to seeing as well. Tran’s was still in a safe range, but 205* on the highway in this weather is not normal (likely bc the coolant was hotter).

Oddly enough, after I stopped for gas, the engine temps didn’t go above 210 going the same speed with higher ambient temps. I may have a bad unit.

I bought a 2791 bc I’m in a time crunch and at a hotel. Sorry @freedom_in_4low for not getting it from u, Amazon has one near me and I don’t want to chance not having it in two days for highway driving or for off-roading this weekend.

This USMW was fine for stop and go, but I need more engagement when on the highway. Not sure if this was a one-off problem, or if the USMW simply doesn’t engage enough for my needs (with two coolers in the grill).

 

[freedom_in_4low]

Didn’t like how hot the rig was on the drive to phx. ETCs hit 230 and that didn’t happen when I drove to Vegas, then to and from Moab, or when pulling a uhaul for 7 hours back from Vegas. My IATs and transmission temps were about 10-20* higher than I’m used to seeing as well. Tran’s was still in a safe range, but 205* on the highway in this weather is not normal (likely bc the coolant was hotter).

Oddly enough, after I stopped for gas, the engine temps didn’t go above 210 going the same speed with higher ambient temps. I may have a bad unit.

I bought a 2791 bc I’m in a time crunch and at a hotel. Sorry @freedom_in_4low for not getting it from u, Amazon has one near me and I don’t want to chance not having it in two days for highway driving or for off-roading this weekend.

This USMW was fine for stop and go, but I need more engagement when on the highway. Not sure if this was a one-off problem, or if the USMW simply doesn’t engage enough for my needs (with two coolers in the grill).

interesting.

I was mostly thinking in terms of the engagement temperature before, but I suppose I can't rule out that the USMW may also not lock up as hard when it is engaged. The only way to check would be to do the FSM test with a tachometer, which I don't have. Amazon has one for $19, maybe I'll get one and try it when it gets warmer.

I definitely do hear it engage and when it's engaged it seems just as loud as the Hayden's did, but my ear is poorly calibrated.

 

[MikeE024]

interesting.

I was mostly thinking in terms of the engagement temperature before, but I suppose I can't rule out that the USMW may also not lock up as hard when it is engaged. The only way to check would be to do the FSM test with a tachometer, which I don't have. Amazon has one for $19, maybe I'll get one and try it when it gets warmer.

I definitely do hear it engage and when it's engaged it seems just as loud as the Hayden's did, but my ear is poorly calibrated.

Sounds good man. I have a feeling it doesn’t engage as much, but that might not matter to folks depending on their needs and location. And it’s possible that I have a bad unit so it doesn’t work like yours does.

I’ll report back after I drive to Tucson with the 2791 installed.

 

[freedom_in_4low]

Sounds good man. I have a feeling it doesn’t engage as much, but that might not matter to folks depending on their needs and location. And it’s possible that I have a bad unit so it doesn’t work like yours does.

I’ll report back after I drive to Tucson with the 2791 installed.

I checked mine today while it was hot and I could not reproduce the play you seem to have in yours.

 

[MikeE024]

I checked mine today while it was hot and I could not reproduce the play you seem to have in yours.

Do the Hayden fan clutches come with fasteners? My stock fasteners are back at home (and had I brought them I wouldn’t have needed them…).

Hopefully I can use the USMW if the Hayden unit doesn’t come with fasteners.

 

[freedom_in_4low]

Do the Hayden fan clutches come with fasteners? My stock fasteners are back at home (and had I brought them I wouldn’t have needed them…).

Hopefully I can use the USMW if the Hayden unit doesn’t come with fasteners.

I don't remember any, and if they did I believe I used my original fasteners anyway.

 

[dbbd1]

Do the Hayden fan clutches come with fasteners? My stock fasteners are back at home (and had I brought them I wouldn’t have needed them…).

No but you can use the old ones. Unless they are part of the problem.

 

[MountaineerTom]

Do the Hayden fan clutches come with fasteners? My stock fasteners are back at home (and had I brought them I wouldn’t have needed them…).

Hopefully I can use the USMW if the Hayden unit doesn’t come with fasteners.

Mine didn’t. I can’t remember the size though. I thought I had it written down somewhere.

 

[MikeE024]

I don't remember any, and if they did I believe I used my original fasteners anyway.

No but you can use the old ones. Unless they are part of the problem.

Mine didn’t. I can’t remember the size though. I thought I had it written down somewhere.

Thanks guys. Hopefully the USMW fasteners will work until I get back to town. That’s what I get for not bringing the original fasteners me.

 

[MikeE024]

Installed the 2791 yesterday and things are all good. Didn’t rev it out on the ride home bc I sheared off the upper CA bracket from the axle