What size serpentine belt?

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Bunch of P30 info Here

One of the things you can do to really help yourself is, do whatever is possible to look 360 degrees all the way around that serpentine belt, to acquire a part number off of it. It may, or may not be on the back side. It all depends how strong the printing was when the belt was originally made. But, if you can get that number, then you're home free as far as a measurement is concerned.

And, many times, a serpentine belt is held in place with a spring loaded tensioner. If you're lucky to have that, you'll more than likely need a 1/2" drive ratchet handle that will fit into the opening for that tensioner. Then, simply pull or push, whichever allows the belt to release tension and, it will slip off of all the pulleys, idlers, etc. Then, you have to work it around the fan blade tips to get it out so you can measure it or, find whatever numbers are on it.

If, as you say, it's been quite a while since it's been changed, I'd definitely get a new one, install it, and keep the old one for emergency service, if and when needed, 'till you can get a new one.
Scott

Get a new belt, install it and keep the old one for a spare.

I wish you well with your mother's situation.

The belt looks perfect but, I know that it's at least 7 years old. I probably need to pull it and have it measured.

If you are concerned about the condition of the belt put your mind at ease and change it before the trip. That way you know you have the right one.

Thanks a lot. My mother is in the UT Medical Center with hours or days left. I have been driving the ten hours round trip twice a week in my car. We are going to take the motorhome and leave it there so that at least we will have a regular place to stay when we get there. When this is all over I will drive it back home. The last thing I can deal with right now is being broken down some place.

Check rockauto.com. They have a listing for several different belts for the Chevrolet P30, including the motor home chassis.