Cummins ISB 340 Engine Overheating Overheat Fan Clutch Thermostat Cooling etc.

[rodrickc]

That's what another friend said.. he wanted to know if the fan was good?

[AcftEngr]

Originally Posted by rodrickc

2011 - It just ran 500 miles for 48 hours before end on sunday... monday went to fuel 1 mile and thats when it bad.

Let me try to add my recent experience. I owe the forum much update but have been waiting for more time in my life.

I found that my issue was not the clutch but the clutch strap (anti-rotation strap). The strap has a small diode in the circuit and once it fails, the fuse pull does nothing. IF you have fluid leaking from the clutch - you will also not get any relief by pulling the fuse!

I have pictures of the strap and clutch....also pics of the strap autopsy that i accomplished to potentially repair the diode. The strap was approx $150 to replace alone and the clutch/strap together was approx $650. After all my efforts - i ended up replacing the clutch/strap assembly.

In the early stages for diagnosis - i tied a pink ribbon (approx 24-36 inches) onto the grill at the rear of the coach. Once the coach is started it will usually blow the ribbon horizontal. I was able to watch the ribbon while driving in the rear camera. As the heat began to rise - in most cases the ribbon was limp.

All in all - i was helping someone fix the coach to sell. Its now with its new owner and not additional issues.

I'll try to include some pics...diode is the black item in the last pic soldered between the two input wires.

[AcftEngr]

Additional Pic of my ribbon....

[RichKimball]

Wow...that's great info. I had a new anti-rotation strap included when I changed my clutch...so this is really good to know.
I did see a diode across the terminals of the fan clutch in the wiring diagram (posted above) but had no idea where it was.
Thank you for your follow-up!

[AcftEngr]

Originally Posted by mevman

Wow...that's great info. I had a new anti-rotation strap included when I changed my clutch...so this is really good to know.
I did see a diode across the terminals of the fan clutch in the wiring diagram (posted above) but had no idea where it was.
Thank you for your follow-up!

I was originally told the diode was on the plug side and it could be replaced. I disassembled the plug and found nothing. That is when I cut into the gray area near the clutch.

As I tried - fuse or no fuse the fan would not work properly.

[rodrickc]

Originally Posted by mevman

The fuse removal is only used to verify the fan clutch is indeed bad. While possible that relays etc can go bad...I don't think in reality they have anything to do with with the Horton fan clutch.
Sad to say you're going to replace the fan clutch. You can do it yourself if you are in fact handy enough where you removed radiator/CAC for the water pump!

I replaced my fan clutch through the bedroom floor access after cutting an 8x10 hole in my fan shroud (initially cut this for easy cleaning of the inside of the CAC/radiator). Sheet metal cover with weatherstripping and self tapping screws holds the air in afterward. The whole clutch fan replacement took me about 1 1/2 hours.....and I was pleased I didn't pay FL $2K to do it. The price of the clutch was the only bad part...but my parts counter clerk gave me a 'good guy discount' of $50 making it $600.

Good luck.

Originally Posted by AcftEngr

I was originally told the diode was on the plug side and it could be replaced. I disassembled the plug and found nothing. That is when I cut into the gray area near the clutch.

As I tried - fuse or no fuse the fan would not work properly.

That is what I am finding out... very frustrating.

[kinein]

Originally Posted by DegoRed

Wanted to add some additional info.

My parts were $300, but I had to buy stuff that broke. If you were just eliminating the fan clutch, the Cummins spacers to do so are probably under $50. Am happy to pass along Cummins pdf installation diagrams to anyone who wants them, also has part numbers, etc.

My fan clutch blew up @ 18K miles +/-

Have noticed no real change in fuel mileage with fan running all the time, seems to be no better or no worse.

Replaced my fan that blew up with original Spartan fan that came with motorhome, did not know that someone made a performance fan.

Will it be possible for me to get a copy of the information you have regarding install and parts list?

[rodrickc]

Originally Posted by rodrickc

2011 - It just ran 500 miles for 48 hours before end on sunday... monday went to fuel 1 mile and thats when it bad.

So... RV novice really didn't take it upon himself to look up under the engine, otherwise he would have seen a broken fan belt hanging down. This could have been done before he took the 5 amp fuse out and realized that didn't work. Or if had taken the right fuse out, the fuse box was mounted upside down. I woke up in my sleep and said of course I took the right one out?? So fan belt and seized up AC compressor seems to be the culprit. I see a bolt is backed out of the AC comp. So hopefully Cummins will get the correct part numbers and I will track parts down and have an experience mechanic do the install. Thanks everyone.

[basketball]

Get rid of the Horton Fan Clutch. Your problems will never go away.
Go to a direct drive multi-wing fan.
These are sold by Superior Turbo for $275. 30" 9 blade.
Larry 517-486-0001, tell him you saw it on IRV2
For spec e-mail Basketball and I will send.
Basketball lbrudzynski@superiorturbo.com[/URL]

[Mlynds]

Originally Posted by basketball

Thanks for info Bob. Did you get a price just for the fan? Will they have to remove rad and CAC? I am in Canada and they want $925.00 cad ($685.00 USD) just for the clutch fan.

Might have to buy one when I am down in your warm country.
Please respond ASAP
Thanks

I am having the same problem the part number i was quoted was hor/9904088 is this the same part because i was quoted over 1900 just for the part. i have a 6.7 cummins on a freightliner chassis.

[RichKimball]

Originally Posted by Mlynds

I am having the same problem the part number i was quoted was hor/9904088 is this the same part because i was quoted over 1900 just for the part. i have a 6.7 cummins on a freightliner chassis.

Call Gaffney with your VIN and ask them. They are often cheaper anyway.
Parts line is* (855) 253-0421‬
Service line is *(800) 385-4357‬

[basketball]

Check post by Basketball. E-mail for specs

[mickey53usa]

This thread very informative - except -
Mine: 2009 Winnebago Destination - Cummins 340 6.7.

Problem: while pulling grades, towing a 2012 Jeep Grand Cherokee, temperature will go to 220 and the Overheat warning comes on. Silverleaf system confirms these temperatures -

If I try and keep the RPMs high, it gets hotter.

If I keep RPMs low (less than 2000) the engine temperature can be controlled.

This has been going on for the last three years and I suspect the fan clutch. Low outside air temperatures do not make a difference. This problem will occur only on pulling grades and these can be 2% grades.

Frustrated enough now that it is going to Freightliner shop when I get home. Yes it is rear radiator and I clean with pressurized water stream, while the engine is still warm, after every trip. Problem persists.

[basketball]

Do you have a Horton Fan clutch on your coach??? Yes continue reading.

I feel your concern. I have a ISBXT 2008 6.7. Same problem, climbing grades coach would overheat. Rad and Cac are clean.
First look
Look at your fan blade and see if there is any dirt in the center blades. The Viscus fluid will leak out of the fan clutch and accumulate on the fan blade. At this point the clutch will not spin at full speed when you need it most, climbing.

In 2008 the fan clutch did not come with a minimum fan speed protection control module new coaches come with this module (Guard Dog) This module uses the signal from the sensor to ensure a minimum of 500 rpm.Without the minimum speed the fan will not be able to engage fully when needed.

If your fan clutch is leaking fluid, this guard dog will not improve your cooling needs. The clutch fan is bad.

Two choices
1.Replace clutch fan and install speed sensor.
2.Install direct drive fan. (Performance fan)