Broke Down - Bad Fan Clutch

[dale farley]

We left Pensacola after church yesterday afternoon, and everything was going good until about 4:15 this afternoon. Filled up with diesel at Love's Truck Stop in Booneville, Missouri, got back on I 70, and within 10 minutes the bus overheated. I was going up a steep grade and had a guard rail on the side of the road. The engine shutoff light came on, so I stepped on the over-ride and tried to make it to the top of the hill, but it died anyway. I was completely blocking the right lane, in the rain, with all kinds of traffic running upon me from behind.

Paulette called 911 while I prayed and worked with the bus until it restarted and was able to limp off the road, in the middle of nowhere. After determining that the fan blade wasn't turning although the bus was about 220, we parked the bus in a desolate lot and headed back to the Love's truck stop in the car. I called Prevost on the way and gave them the Love's address to overnight a new clutch. It was almost 5 p.m. by then.

A few minutes later, it dawned on me that there should be a way to lock the fan so it would turn all the time. I caught the Prevost mechanic before they closed, and he told me how to locate the four bolts and lock the fan. Fortunately, Paulette was able to use her Droid technology and locate a campground about 2 miles from the Love's Truck Stop. I installed the bolts and drove the bus the 15 miles to the campground. So the good news is that we have the bus running and full hook up for the night.

The mechanic told me I could drive without installing the new clutch, but it would result in horrible fuel mileage. We are about 1400 miles from our destination (Yellowstone).

I have a couple questions: How much trouble is it to replace the clutch? I have a full set of hand tools but no special tools?

Has anyone locked their fan and monitored their fuel mileage until a permanent fix was made? Thanks in advance, Dale

[garyde]

Hi Dale. I remember someone posting last year about changing out their clutch with photos. Any mechanic shop should be able to swap it out.

[ajducote]

Dale,

I changed my fan clutch. See this article.

http://forum.prevostownersgroup.com/content.php?20-Series-60-Fan-Clutch-by-Andre-Ducote

It is not a real hard job, just takes time and patience.

[Sid Tuls]

Dale, when you said step on the override what is that and where is it located? I sure would like to find out what that is. Thanks

[dale farley]

Sid,

The override switch is a black switch on the left side of the driver's floor area that allows you to mash it and get off the road when the bus starts shutting down for one of various reasons.

[dale farley]

Andre,

Great article. Thanks. I just realized that I did not verify my electrical connection to the fan. Does anyone know where this comes from and if it is 12 volt? Can I connect a voltmeter to the connector and turn on my dash air and expect 12 volts to be there? I may have ordered a clutch that I don't need. At the time, all I was thinking about was covering all my bases so I could have the part delivered tomorrow.

[Sid Tuls]

Dale sorry about bugging you since you got your own problems but does every prevost have this override? I'm in the bus and don't see any black switch on the left side. Could it be on the footrest on the left side? Thanks for your time and hope you get your problem fixed:)

[dale farley]

Sid, I thought all Prevosts had the switch. Mine is on the floor about 6 inches to the left of my steering column. Maybe they moved it or discontinued it at some point.

[ajducote]

Dale,

I am not sure of the best way to check the voltage. Maybe you could make up a pair of wires to extend the wires out past the rear of the engine, then run the engine and turn on the dash air. You should get 12 volts at the end of the wires.
Maybe someone else can tell us where the power comes from.

[ajducote]

Sid,

On my bus the over ride switch is on the left side switch panel. It is the last switch to the left of the steering column.

[dale farley]

I see that the Prevost manual says the fan is controlled by the engine coolant temperature and air inlet temperature, but there are no other details, so that doesn't help me very much.

[Sid Tuls]

Dale & Andre, Thanks I found it on the dash:) Well I learned something today! Thanks

[Larry W]

Dale
Do not know about poor fuel mileage with the fan locked. We just made a 2000 mile trip from Montrose, CO to Helena, MT and back with the dash air on for the entire trip. The fan runs all the time the dash air is on. The pro-driver showed 7.4 mpg for the trip.

[dale farley]

Larry,

I was thinking that same thing, since I am running my dash air all the time. I may just wait until later to change the clutch. Thanks

[Jon Wehrenberg]

The fan has been reported as requiring up to 30 HP so running with it locked up is going to impact mileage. The use of the small bolts to lock it should be considered a temporary fix. For those unaware I think there was an article I posted once that shows the details of locking the fan blade.

The quickest way to destroy an engine is to overheat it. For this reason all owners should make absolutely certain they scan the engine gauges regularly. In very hot weather we can see the engagement and disengagement of our fan blades by watching the engine temp cycle up and down. There are two stages, one at 204 and one at 208 (going by memory so these are guesses) and they should be detectible. The use of the over ride should be considered an emergency procedure only and continued use may damage the engine.

[george frudakis]

Jon
Could you please give me the article that you posted on detail of locking the fan blade. I am new and would like to see this just in case i need to do this procedure.

[Jon Wehrenberg]

George,

Go here and scroll down to the article.

http://forum.prevostownersgroup.com/content.php?21

[truk4u]

Dale,

Here is Andre's post for the fan change out.

http://forum.prevostownersgroup.com/content.php?20-Series-60-Fan-Clutch-by-Andre-Ducote

[dale farley]

The Prevost Maintenance Manual also shows the location of the bolts on page 5-13. I continuallly monitor my gages while driving and had seen nothing unusual all day. When I left the truck stop, within 10 miles, I was hot and the light came on. I verified there were no leaks and that the fan was barely turning. Because of time constraints, I somewhat panicked and ordered the clutch before Prevost closed for the day. In retrospect, I should have verified my 12V connection to the fan clutch before ordering a new one. I find it difficult to believe that the clutch would just fail all at once unless electrical problems are involved, either internal to the clutch or external.

[Jon Wehrenberg]

The clutch is controlled by DDEC and all I know is it is a two stage, with the first lower speed stage kicking in around 204 and the second and higher speed fan stage at around 208 (going solely based on memory). The signal to the fan clutch is via DDEC. I don't know anything about how it works or if there is a test to determine if the DDEC output is functioning, but that is where I would start checking. My guess is if the connection has been good, it is not likely it would suddenly go bad. I can envision a bad or broken ground wire though.

[dale farley]

Thanks to the Good Lord, some excellent advice from the forum,and some assistance from Paulette, we are back on the road. Received the clutch at 10:30 this morning, and by 2 P.M. we had finished the install and adjusted the fan a couple times to make sure it was centered. Got a shower and we're now 260 miles down the road. Everything worked as it should once I finished the install, so maybe it was just a freak failure. Nothing that $1542 and 3 1/2 hours labor couldn't fix!!! Thanks to everyone for their input.

[ajducote]

Dale,

Great news! I happy to hear it all worked out. You got it done faster then I did!
Safe travels...

[dale farley]

Even after a very slow start yesterday, we were still able to cover 494 miles before stopping about 50 miles North of Sioux City, Iowa. Pulled in a rest area and ran the generator and two ACs all night. Hope to be in Wyoming this evening.

[Kenj]

Dale sorry about bugging you since you got your own problems but does every prevost have this override? I'm in the bus and don't see any black switch on the left side. Could it be on the footrest on the left side? Thanks for your time and hope you get your problem fixed:)

Mine is on the lower left hand dash panel, bottom row, 3rd toggle switch from the left

[Sid Tuls]

Thanks, thats where mine is also. Just keep learning more stuff as we roll along:cool:

[dale farley]

70597060 A couple pictures of the old man that helped Paulette replace fan clutch. Not an ideal situation, but we got the job done anyway.

[dreamchasers]

I'm impressed!

Hector

[GDeen]

Good work Dale.....the part about being broken down in the rain blocking traffic had me cringing.....glad you guys are underway.