Alternator Replacement

[Cj D]

Hey all. I have a 2008 Monaco Cayman since new. The alternator finally died. The Alt Chrg light is illuminated and the battery voltage remains at 12v without rising after the engine is started. So, a couple questions....

First, I can drive the RV, using the Genset to maintain the chassis batteries until I order a replacement alternator. So I hate to remove the old until I have the replacement in hand. But, I cannot find the part number. So, is this a standard 160 amp alt for Monaco’s , or do I have to remove the old alternator to get the part number? Monaco does not answer their phone and has not responded to emails.

Second...last year I had to pull the cooling unit to do some work on the engine. I am not real keen on removing the unit again if I don’t have to. I can easily reach the alternator from the cabin hatch, but not sure if I can reach the belt tensioner. Does anyone have first hand experience? Just for planning do I need to remove the cooling unit again, or can I do this from the hatch?

[gmc70]

I do not have the same MH as you but if can reach the alt. to change as I can then you shouldn't have to remove much else. As far as the tensioner it maybe a two person job as on ours. One under and one in the hatch.

[jacwjames]

Do you have a copy of the build or data sheet on your rig. On mine it lists the alternator.



You might be able to take a picture of the data plate on the alternator.

[klcdenver]

I suggest you contact Superior Quality Starters and Alternators | AJ-Elec.com. Phone 828-369-0118. He is very knowledgeable and has great service and price. Where ever you get one make sure it has the correct pulley on it because they can be a bear to get off the old one. Good luck.

[RonaldNC]

Originally Posted by Cj D

Hey all. I have a 2008 Monaco Cayman since new. The alternator finally died. The Alt Chrg light is illuminated and the battery voltage remains at 12v without rising after the engine is started. So, a couple questions....

First, I can drive the RV, using the Genset to maintain the chassis batteries until I order a replacement alternator. So I hate to remove the old until I have the replacement in hand. But, I cannot find the part number. So, is this a standard 160 amp alt for Monaco’s , or do I have to remove the old alternator to get the part number? Monaco does not answer their phone and has not responded to emails.

Second...last year I had to pull the cooling unit to do some work on the engine. I am not real keen on removing the unit again if I don’t have to. I can easily reach the alternator from the cabin hatch, but not sure if I can reach the belt tensioner. Does anyone have first hand experience? Just for planning do I need to remove the cooling unit again, or can I do this from the hatch?

I replaced my alternator a couple of months ago. Since my Cayman is a year newer, the part may not be the same. The original alternator was a Leece-Neville 110-566P. Leece-Neville is now owned by Prestolite. They don't make that model anymore, but the replacement is a Prestolite AVI143P. I bought mine at NAPA. It looks pretty much the same, but the terminals are a bit different. I called the company and they were very helpful. The main difference is that the Alt Fail Relay connection should be attached to Terminal W.

The most difficult part of the replacement is physically getting to the alternator. My buddy and me ended up removing the air filter assembly on the left side (3 bolts) and crawling into the space to reach the alternator. Much easier than removing the radiator and CAC! However, it's still not easy. We ended up needing to extend one of the wires to reach the alternator. Very doable project, but you will be sore the next morning!

I should also mention that once completed, I'm not sure it was the alternator after all. When replacement the alternator, I discovered that the power cable connection to the starter was loose. After examining the schematics, I realize that Monaco routes power from the alternator to the main bus in the battery compartment, back to the starter post, back to the batter compartment... weird. I was so far along with the replacement that I finished the job. Later, I took the alternator in to get it tested... and it was fine! Oh well.

Moral of the story... check all your connections from the alternator, battery compartment and starter first.

Let me know if you need more information.

Ron

[jacwjames]

Mine was easier to get to since I have a side radiator but still a little bit of a chore to get to the wiring. Make sure you mark the wires. When I was removing mine I turned all both battery disconnects but found I still had power going to the alternator, turned out it was the solar backfeeding, pulled the solar fuse and got the alternator totally isolated.
I did not buy a new alternator but took it in to be rebuild, cost was ~$180 and they had it done in a day, I probably could have waited on it.

There are people who have been successful in swapping with another brand that is not a DUVAC system but it takes time/knowledge that I did not have, easier to just stick with what worked.

[Cj D]

Thank you all for the excellent responses! Ron, I will definitely check the connections. I went through the battery compartment, but have not worked my way to the starter connections yet. I wish I had spent more time taking pictures when I had the cooling unit out. I cannot visualize the tensioner since it was so long ago. As long as I can get to that, the alternator replacement should go smoothly.

I’ll update how it goes...and thank you all again!

[jacwjames]

Also check in your electrical compartment. I have a small fuse holder labeled DUVAC which I assume is for the alternator.

I have an 8.3 ISC, different engine, but the tensioner has a hole for 1/2 drive so if you have a ratchet or breaker bar you can use that to gain leverage.

Heres a link to an ISB, yours may be slightly different but you can see the tensioner pulley in the first post.
https://www.irv2.com/forums/f123/isb...ey-430171.html
It is the one below and to the right of where the arrow is pointing.

[Cj D]

Thanks, Jim. That pic refreshes my memory. I remember now when my drive pulled out and I rapped a pretty good cut on my knuckle from hitting the sharp edge of the fan. Guess I had repressed the memory.

I used Ron’s part numbers and ordered a new 200 amp alternator. Soon as it gets here I’ll dive in.

Thanks again for the help

[Cj D]

Well, the good news is the alternator can be changed from the hell hole in the cabin. The bad news is I ordered the 110-566P alternator, and that is a totally different mounting system. Apparently it did change from 2008 to '09. JTI trucking doesn't want to take the return, so I may be out $281. Bummer.

The worst part, though is i cannot find the actual alternator. It is a Leece Neville 110-923, which crosses to a 10-923...and then goes dead. NLA. It is a standard pivot bolt mount, so I will have to find a similar replacement that will fit and work.

I do have a question about the "DUVAC". Is DUVAC standard on all RV's? The reason I ask, is in all the references to DUVAC alternators I have seen there are 2 small wires to the alternator. One ignition and 1 duvac. My alternator only has a single small wire. Is it possible my alternator is not DUVAC??

This is the typical project. I thought the hard part would be removing the alternator. It turns out that was easy, the hard part is finding a replacement.

[Timaz]

Why not just have it rebuilt like Jim did. Then everything will be the same.

Tim

[RonaldNC]

Originally Posted by Cj D

Well, the good news is the alternator can be changed from the hell hole in the cabin. The bad news is I ordered the 110-566P alternator, and that is a totally different mounting system. Apparently it did change from 2008 to '09. JTI trucking doesn't want to take the return, so I may be out $281. Bummer.

The worst part, though is i cannot find the actual alternator. It is a Leece Neville 110-923, which crosses to a 10-923...and then goes dead. NLA. It is a standard pivot bolt mount, so I will have to find a similar replacement that will fit and work.

I do have a question about the "DUVAC". Is DUVAC standard on all RV's? The reason I ask, is in all the references to DUVAC alternators I have seen there are 2 small wires to the alternator. One ignition and 1 duvac. My alternator only has a single small wire. Is it possible my alternator is not DUVAC??

This is the typical project. I thought the hard part would be removing the alternator. It turns out that was easy, the hard part is finding a replacement.

Wow, Sorry to hear this. You should probably find a place to rewind your alternator... simplest solution.

However, I looked up your Neville 110-023 up on Prestolite's site (current owner of Leece Neville). The 110-023 crosses to LBA2195, which crosses to A001090875. I found one for sale at:

https://store.aj-elec.com/catalog/pr...6bb15524e6a0bf

You might also give Prestolite a call... they were very helpful with my replacement.

Good luck!

Ron

[CountryB]

Originally Posted by Cj D

I do have a question about the "DUVAC". Is DUVAC standard on all RV's? The reason I ask, is in all the references to DUVAC alternators I have seen there are 2 small wires to the alternator. One ignition and 1 duvac. My alternator only has a single small wire. Is it possible my alternator is not DUVAC??

The DUVAC was used on the older Coaches (pre-2003 I think. Someone can correct me if I'm wrong on the end date).
After the Duvac system, most coaches went to a "Battery Isolator" setup like the IntelliTec BIRD/Big Boy.

If you have a DUVAC you should see something that looks like this (the blue box) in your battery-electrical compartment:

[twinboat]

A Dulvac alternator will work fine, just don't connect a wire to it.

The Dulvac system was a workaround for diode battery isolators. The alt couldn't sense battery voltage thru the isolator so a sense wire was added directly from the battery to the internal voltage regulator.