Fun with engine belt (Caterpillar)

Fun with engine belt (Caterpillar) - Printable Version

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Fun with engine belt (Caterpillar) - bikestuff - 04-17-2013

Gang,

When I bought my 03 with a C-12 Cat engine two years ago from Newell, it slung its serpentine belt off while I was on my out of Miami. Back to Newell. They advised to go to Fabick Caterpillar in Joplin. That is the start of a very long story that involves many trips to Miami and a couple to Joplin.

The good news is that the problem has now been found and fixed!

My symptoms were: 1) Belt wanted to "ride up" on some of the pulleys. 2) Belt would sometimes just break. 3) My AC compressor would kick on and off and when On the belt would really flop around. (like the compressor was pulling too hard). 4) The belt (or pulleys) squeaked when the engine was running.

Newell / Fabick replaced (over time) replaced all of the pulleys and the tensioner. Problem would seem better and then would return.

Yesterday at Thompson Caterpillar in Birmingham, I believe the problem was solved once and for all.

It turns out that there were many problems all combining to create this issue. Here are the problems in (my ranking) in descending order of severity.

1) The wrong tensioner was installed when the engine was installed in the Newell (10 years ago). The old tensioner which was a custom application (would hit its limit before taking all the tension out of belt. The new one (correct one for C12) has much more turn radius to take more tension out.
2) There was a subtle nick in the Alternator pulley that was grinding one of the grooves from the belt. (nick was filed off).
3) All of the problems with belts had filled the "teeth" of pulleys with old rubber making for less friction and more slipping.
4) The replaced pulleys were not installed with bearing "centerers". The front bearings on the two large pulleys were free to wobble around the bolt that holds them on.
5) One of the large pulleys had a completely bad bearing.

The long and short of this episode is that its actually pretty simple to diagnose belt problems. (at least for a Cat with serpentine belt).

1) take belt off and hand turn the pulleys by hand. They should turn easily and you should not feel any "grinding". If you spin them they should gradually slow down and not stop suddenly. If not suspect a bearing problem.

2). Closely inspect the teeth on the pulleys. (any nick or rough spot will gradually sand down your belt).

3). Check the operation of your tensioner by ensuring that it is not hitting the stop on the tight side.

4) Check the operation of the belt with the engine AC compressor on and off. In my case, the belt was fine if the compressor was off. If the belt flops around a lot during operation, you have a problem to find. Do not accept advice from anyone that says this is "Normal" for this engine. I still can't believe that I bought that one. Smile

5) Using a long metal ruler ensure that all the pulleys are parallel and in the same plane.

Going forward...I have learned a few lessons:

1. Draw a belt routing map and keep it near the engine. My engine has lots of pulleys and such and a map will help you put a belt back on if it breaks.

2. Keep a spare belt with you at all times.

3. Inspect your belt and pulleys carefully. I was once running with a 7 groove belt instead of the normal 8 groove belt. (The other one had been ground off).

4. I dont believe that belt replacement is on the Newell maintenance checklist...but it IS on mine. My belt will now be replaced once / year.

Hope this helps someone.

Cheers,
bill
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RE: Fun with engine belt (Caterpillar) - rheavn - 04-17-2013

Bill,
Outstanding post. The concepts you describe can be applied to any of our engines. Glad to hear you found the right guy to fix it. Good reminder that getting a second opinion many times helps. Also did the Cat tech talk about a maintenance schedule for the belt tensioner?

RE: Fun with engine belt (Caterpillar) - bikestuff - 04-17-2013

Nope. I think that is on an as needed basis. I wish I could post the video that I have. It shows the belt with virtually no movement. I think all the other problems would have shortened the life of the tensioner....but again....the tensioner was near the limit so did not get exercised through its normal allowed movement. (hard to say, but easy to understand once you get it).

RE: Fun with engine belt (Caterpillar) - rheavn - 04-17-2013

Bill,
Your post is very clear & I understand the tensioner movement issue. I asked about tensioner replacement because on my Country Coach with the Cummins there was a mileage checking and replacement recommendation. I don't have the auto belt tensioner on my DD.

RE: Fun with engine belt (Caterpillar) - Johnc - 05-06-2013

(04-17-2013, 08:03 AM)rheavn Wrote: Bill,
Your post is very clear & I understand the tensioner movement issue. I asked about tensioner replacement because on my Country Coach with the Cummins there was a mileage checking and replacement recommendation. I don't have the auto belt tensioner on my DD.

From Newell's generic PM sheet:

Every 12 months-
Check belts, hoses, engine, generator and blower motor".
Inspect fan idler pulley, hub and belt tension

Every 2 years- Change engine belts

Cat C-12 engines are very rare in Newell coaches. I can recall Ward Burton driving a Caterpillar supported race car in 2003, and Cat supplying us with a special C-12 engine for his coach (653). Fabick Cat would have provided all the engine accessories, as we were using Detroit Diesel as standard in 2003.

I have not seen any mileage recommendations for idler pulley replacement.

RE: Fun with engine belt (Caterpillar) - bikestuff - 05-06-2013

John,

Thanks for the post. What is not clear to me is what does Newell mean by every two years. Is that something that Newell monitors or is it up to the coach owner to request? My coach has been maintained by Newell for several years. (Two and half years with me as owner). As far as I know, no one ever asked me about the belt.

That makes me think about the generator as well. Do I need to create a log to monitor belts and such.

I think I have been confused by the "annual maintenance". I believed that if I said its time to do "annual maintenance" Newell would do what was needed. I am now thinking that I need to take a little more responsibility.
Smile

Any one else want to chime in? How do you track all the stuff that needs to be done to your coach?
Engine, generator, Aquahot, water filters and dump valves...there is a lot that needs periodic maintenance and it is far more than I can keep in my head.

Cheers,
bill

RE: Fun with engine belt (Caterpillar) - Trainer - 05-06-2013

Bill,

With regards to tracking your Aqua Hot maintenance, I can offer two suggestions.

If you wish to have annual service per the calendar, then mark the month and year of the fuel filter change on the filter where you can see it when you open the compartment door.

Or, you can visually check the exhaust when the burner is running to see if it is showing any vapor (white smoke) or if it is smelly (really hard on a Newell with roof exhaust). Annual service will result in a clear exhaust with very little smell. If that is your situation, you might wish to continue using the burner till it starts to smoke a little bit.

Hope this helps you.

Rudy

RE: Fun with engine belt (Caterpillar) - bikestuff - 05-06-2013

Thanks for the the thoughts Rudy! I like the idea of doing things on a schedule....and performing a little more maintenance than actually required. The problem that I ran into with the aquahot was that annual "maintenance" did not fix the problem that was there. I had constant problems with that thing and was seriously considering replacing the whole she-bang until I found the overflow tube leaking. Now all is well.

A year from now I know that I need to do maintenance again. (even if not smoking I will probably get it looked at anyway).

But how in the world do you remember things that need to be done every 2 years (or three years or 10 years)???

I think that I need to invent a logging app for my iPhone! Smile

RE: Fun with engine belt (Caterpillar) - rheavn - 05-06-2013

Bill,
I have a maintenance spreadsheet that covers the entire coach. I also have one that covers the AquaHot and genset. Mine is a combination of manufacturer recommendations and my own experience. Email me if you want a copy.

RE: Fun with engine belt (Caterpillar) - Johnc - 06-04-2013

Attached is the current Newell service and preventative maintenance checklist. It's fairly generic in nature, but being in MS Word format, you could easily customize it to your coach