Jeff H Posted July 17, 2023 Share Posted July 17, 2023 Last night, fortunately only about 2 miles from home the alternator light came on. I stopped to un hook the towed about 1/8 of a mile from home and could smell something hot and figured something was seized and the belt was next. As I just finished unhooking the belt broke. I idled the last bit home and by the time I backed in I was up over 200deg. When I checked the belt was gone. The alternator will turn then stop and turn again with a bit of force. So I know that it is better to rebuild then replace the alternator. My questions are: 1. What is the best way to get it off? There doesn't look to be much room to work and 2. What belt does it take? Finally I was lucky to be close to home when it happened otherwise I might have spent the night on the side of the road. Is there a way to bypass the alternator with a belt so you can keep the fan and water pump working? Link to comment Share on other sites More sharing options...
Dr4Film Posted July 17, 2023 Share Posted July 17, 2023 (edited) Unless you can find the exact size Serpentine belt that would fit without going around the alternator pulley, you are basically out of luck. It is easier to by pass the AC compressor as it generally has its own belt. If you can't seen to get to the two mounting bolts I would look for a mobile diesel mechanic plus find yourself a good rebuild shop to rebuild your alternator to factory specs. Did you keep what was left of the old belt as that may have had some numbers on it so you could purchase a new one? Edited July 17, 2023 by Dr4Film 1 Link to comment Share on other sites More sharing options...
klcdenver Posted July 17, 2023 Share Posted July 17, 2023 You can go to Cummins Quick Serve and get your belt part number. I have a 2007 Diplomat with a 400ISL and the P/N is 3972263. That is a cummins number and can be crossed to other brands. Link to comment Share on other sites More sharing options...
det944 Posted July 17, 2023 Share Posted July 17, 2023 My owners manual for my Dynasty lists belt part numbers. You may need to cross reference different manufacturers but would be a starting point. Link to comment Share on other sites More sharing options...
Jeff H Posted July 17, 2023 Author Share Posted July 17, 2023 2 hours ago, Dr4Film said: Unless you can find the exact size Serpentine belt that would fit without going around the alternator pulley, you are basically out of luck. It is easier to by pass the AC compressor as it generally has its own belt. If you can't seen to get to the two mounting bolts I would look for a mobile diesel mechanic plus find yourself a good rebuild shop to rebuild your alternator to factory specs. Did you keep what was left of the old belt as that may have had some numbers on it so you could purchase a new one? I didn't see it on the road so I thought it must have got thrown up into the engine bay but I dont see any parts there. I will go back and have a look where It broke Link to comment Share on other sites More sharing options...
Jeff H Posted July 18, 2023 Author Share Posted July 18, 2023 2 hours ago, klcdenver said: You can go to Cummins Quick Serve and get your belt part number. I have a 2007 Diplomat with a 400ISL and the P/N is 3972263. That is a cummins number and can be crossed to other brands. Thank you 2 hours ago, Jeff H said: I didn't see it on the road so I thought it must have got thrown up into the engine bay but I dont see any parts there. I will go back and have a look where It broke I looks like there are 4 bolts 2 top and 2 bottom. I can't get the top to budge. and there is not much room for a bigger ratchet/bar. it looks like the way to do it is to take the bottom bolts out and then one person remove the top bolts from inside and someone below support it and then lower it. Link to comment Share on other sites More sharing options...
MyronTruex Posted July 18, 2023 Share Posted July 18, 2023 Just a quick tip. You have a different model than mine which is an SKQ. There was a hidden floor piece under the edge and going into the closet on my engine hatch cover. This opening was well hidden with carpet that had not been cut around the edges inside the closet. It took some time to find and I had to remove the closet doors and bottom railing of course. I changed my belt by myself and it was a struggle for sure moving the tensioner. Using a ratchet strap to pull the breaker bar was a real hazard but got the job done. 1 Link to comment Share on other sites More sharing options...
klcdenver Posted July 18, 2023 Share Posted July 18, 2023 You can open your engine hatch and with a mirror look towards the rear and you can tell if you have the second hatch or not. Another tip get a piece of pipe that will fit over your ratchet or breaker bar to make an extension and leverage to get the bolts that are hard to reach from the weird position you will be in trying to reach them. If you are built like a snake it helps. Good luck. 1 Link to comment Share on other sites More sharing options...
Dr4Film Posted July 18, 2023 Share Posted July 18, 2023 Sorry for not considering that your coach has a rear radiator which makes the task of working on the engine 1000 times more difficult. All the more reason to hire someone to do the task. My two diesel coaches have been side radiators. I have not and will not own a rear radiator coach. 1 Link to comment Share on other sites More sharing options...
Jeff H Posted July 19, 2023 Author Share Posted July 19, 2023 10 hours ago, Dr4Film said: Sorry for not considering that your coach has a rear radiator which makes the task of working on the engine 1000 times more difficult. All the more reason to hire someone to do the task. My two diesel coaches have been side radiators. I have not and will not own a rear radiator coach. I wont disagree with that. I got it out Getting the wires off was as much work as getting the bolts out. Not that hard once you get twisted around so you can get some leverage. Had to remove the tail pipe from the muffler to make room for me. 11 hours ago, myrontruex said: Just a quick tip. You have a different model than mine which is an SKQ. There was a hidden floor piece under the edge and going into the closet on my engine hatch cover. This opening was well hidden with carpet that had not been cut around the edges inside the closet. It took some time to find and I had to remove the closet doors and bottom railing of course. I changed my belt by myself and it was a struggle for sure moving the tensioner. Using a ratchet strap to pull the breaker bar was a real hazard but got the job done. Hmm. I will have to look for the second hatch. I am not looking forward to the belt 1 Link to comment Share on other sites More sharing options...
Solution Scotty Hutto Posted July 19, 2023 Solution Share Posted July 19, 2023 Jeff, There’s another recent thread with info on alternators (but not belts) for 2006 Diplomats. Since your coach does not have a DUVAC alternator, you might rethink rebuilding your old L-N. You may be able to use a Delco 28si or similar, or purchase a new L-N for close to the cost of a rebuild. I searched for a reputable rebuild shop for quite a while, and when I found one the cost of the L-N brand parts plus the rebuild was a major portion of the cost of a new alternator. Also, I would rely on Cummins QuikServ before the owners manual for this specific part. My owners manual for my 2006 Dip had the incorrect part number for the belt. (And I only have one belt for the AC compressor and alternator, not two separate ones as indicated in the Owners Manual.) This is from the Dealer Parts list for my 2006 Dip: …and this is from the Owners Manual: Both came from Monaco 🤦🏻♂️ Link to comment Share on other sites More sharing options...
Jeff H Posted July 19, 2023 Author Share Posted July 19, 2023 Is there any advantage to a higher amperage altenator? Link to comment Share on other sites More sharing options...
Jeff H Posted July 22, 2023 Author Share Posted July 22, 2023 New alternator and belt on their way. Thank you all Now to figure the tensioner Link to comment Share on other sites More sharing options...
jacwjames Posted July 22, 2023 Share Posted July 22, 2023 Go to the Cummins Quickserve site for tensioner part number. Then shop around, lots of aftermarket options I actually found a New Old Stock NOS on ebay Cummins part for a real good price, ~$55. Change mine at ~110K miles and kept the old as a spare. Quote Link to comment Share on other sites More sharing options...
Jeff H Posted July 25, 2023 Author Share Posted July 25, 2023 Thank you all for the help Wasn't as bad as I thought. A second person makes a big difference. Hopefully it runs for another 78000 1 Link to comment Share on other sites More sharing options...
Agpopp Posted July 25, 2023 Share Posted July 25, 2023 26 minutes ago, Jeff H said: Thank you all for the help Wasn't as bad as I thought. A second person makes a big difference. Hopefully it runs for another 78000 Glad you got it fixed. I have a rear rad also, so i know what you were working with! What alternator did you go with for future reference? Link to comment Share on other sites More sharing options...
Jeff H Posted July 26, 2023 Author Share Posted July 26, 2023 On 7/24/2023 at 11:22 PM, Agpopp said: Glad you got it fixed. I have a rear rad also, so i know what you were working with! What alternator did you go with for future reference? i got a Dixie 109-16128 Alt.LBP 12V/160A. Thank you to Scotty for pointing out it is not a DUVAC alternator and rebuilding was not necessary. The guy on the said you can not rebuild for what it costs to buy new. By the time you pay for parts and shipping you will have spent more than a new one. Physically it is an exact match. Link to comment Share on other sites More sharing options...
Agpopp Posted July 26, 2023 Share Posted July 26, 2023 Awesome, love to see part numbers we can cross in case of road breakdowns. Thanks! Link to comment Share on other sites More sharing options...
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