Fan Clutch

[Admorrow]

So I just replaced my Fan Clutch still isn’t working at idle. My old clutch was the OEM AA clutch truck is a 2011 I’ve put 70k miles on this truck since I’ve owned it and only heard the clutch engage once pulling a a grade a WOT it hit 217 engaged and dropped down.

I’ve always had lackluster AC at idle and was planning to add a pusher fan. Anyways a week or so before I replaced the fan clutch the AA oem one started working with the AC out of no where running full tilt when head pressures were high. I decided to replace is and the fan bracket bearing at the same time. I replaced it with a Hayden. I have around 50 miles on it so far I’m monitoring fan speed on my MM3 max speed I’ve seen has been 900 at idle it stays a 180-230 rpm while the AC head pressure is insanely high and cycling. I checked PWM% and it’s at 95 while rpm is 180-230 at idle.

There is a tad bit of corrosion in the plug on my engine harness. I cleaned it and checked voltages two pins had 5v two had nothing and one had 3.67v

This is driving me absolutely insane does anyone have any ideas?

 

[BigPapa]

So, your fan clutch was working but you replaced it?

 

[Admorrow]

So, your fan clutch was working but you replaced it?

Yes it was a AA clutch with almost 300k miles

 

[Topzide]

Lack luster A/C sounds more like an A/C problem and not a fan clutch problem. Also sounds like the clutch was doing it's job. 217 on grade towing, then dropping sounds about right. I just had to check A/C with gauges due to not acting right. Found a bit low. Topped off and am monitoring for any more problems. Truck has 160K and as far as I know, hasn't had A/C repairs. Could be wrong, But would check the A/C also. Hope you didn't get a bad clutch and have to redo the job!

 

[Admorrow]

I replaced my whole AC system after I lost a compressor last year during summer because of high head pressures. Works perfectly with airflow over the condenser. I'm hoping it's not a bad clutch also luckily it is pretty easy to change on these trucks.

 

[Topzide]

Like the idea of a pusher fan to help with the cooling, but since diesels like to be warm, kinda a hard decision on that idea. Fingers crossed that you'll get it figured out soon.

 

[Admorrow]

I know alot of people seem to do it, but Id rather try to fix the issue with the fan clutch and see how it performs first.

 

[AH64ID]

Have you checked for fan speed codes? They will often set and not light the MIL.

Also, have you checked with the tuner to see if any of the fan settings were messed with?

Lastly, lots of the aftermarket fans get horrible reviews for underperforming. The recommendation is to stick with OEM cooling fans for the best performance, especially with the AC.

 

[Admorrow]

I would have done one already if there was a good way

Like the idea of a pusher fan to help with the cooling, but since diesels like to be warm, kinda a hard decision on that idea. Fingers crossed that you'll get it figured out soon.

to g

Have you checked for fan speed codes? They will often set and not light the MIL.

Also, have you checked with the tuner to see if any of the fan settings were messed with?

Lastly, lots of the aftermarket fans get horrible reviews for underperforming. The recommendation is to stick with OEM cooling fans for the best performance, especially with the AC.

No codes is has CTT tunes so I’m SOL there. I just towed GCW of 24k in 70* water got temp to 223 and fan didn’t ever fully engage. Thinking I’m going to send this guy back and order a oem one.

 

[Tuesdak]

Fan clutches have a known life of 5 years. Replacements of clutches this old and older are not "throwing parts at it." The A/C is the first to suffer from: lack of airflow = overheating condenser = high head pressures = exceeding the design pressures of the compressor = system vents refrigerant and/or compressor fails. "Old" fan clutches are slow to lock up when the ECM asks it too and this slow delay allows the head pressure on the A/C to rise quickly from no condenser airflow. The engine heats up slower thus a old slow to lockup fan is not as noticeable via ECT.

You don't need any fan for A/C when going over ~45 MPH.

If you can monitor Fan commanded % and Fan RPM. Offhand ~600 RPM at idle is unlocked. Slower RPM at idle (450 RPM or less) is a weak fan clutch. A/C wants ~1200+ Fan RPM at idle. Fan is overdriven so engine RPM is not the faster fan RPM.

 

[Admorrow]

Fan clutches have a known life of 5 years. Replacements of clutches this old and older are not "throwing parts at it." The A/C is the first to suffer from: lack of airflow = overheating condenser = high head pressures = exceeding the design pressures of the compressor = system vents refrigerant and/or compressor fails. "Old" fan clutches are slow to lock up when the ECM asks it too and this slow delay allows the head pressure on the A/C to rise quickly from no condenser airflow. The engine heats up slower thus a old slow to lockup fan is not as noticeable via ECT.

You don't need any fan for A/C when going over ~45 MPH.

If you can monitor Fan commanded % and Fan RPM. Offhand ~600 RPM at idle is unlocked. Slower RPM at idle (450 RPM or less) is a weak fan clutch. A/C wants ~1200+ Fan RPM at idle. Fan is overdriven so engine RPM is not the faster fan RPM.

Through my stocker back on to get it home the AA clutch and it’s working now. Brand new Hayden was spinning 180 rpm at idle. No dealer had a new one in stock near me so I’ll have to order it.

 

[lpennock]

Aftermarket fan clutches have a pretty bad reputation on these trucks.

 

[Admorrow]

Aftermarket fan clutches have a pretty bad reputation on these trucks.

I read just about the same bad for oem compared to Hayden and know a local shop that uses Hayden if they can’t get oems so I was hoping I’d get away with it. Lesson learned.