How Do I Know Which Belt To Use

I have a 97 Grand Prix SE and it seems there are two different size belts. One is 93" and the other is 93 1/2". How do I distinguish which one to use?

That is correct. There is a first and second design serpentine drive belt for the '97 model year. It depends on which alternator you have and its pulley size and whether you have a 3" tensioner pulley. Most '97 SE/GT/GTP with the Series II 3800 engine use the longer 93 1/2" belt but you may have to take your belt off and measure it to be safe.

Gatorback Gatorback Part # 4060935 93 1/2" BELT - Matches AC Delco 6K935
Gatorback Gatorback Part # 4060930 93" BELT - Matches AC Delco 6K930

That is correct. There is a first and second design serpentine drive belt for the '97 model year. It depends on which alternator you have and its pulley size and whether you have a 3" tensioner pulley. Most '97 SE/GT/GTP with the Series II 3800 engine use the longer 93 1/2" belt but you may have to take your belt off and measure it to be safe.

Gatorback Gatorback Part # 4060935 93 1/2" BELT - Matches AC Delco 6K935
Gatorback Gatorback Part # 4060930 93" BELT - Matches AC Delco 6K930
Just to add to Bob's usual comprehensive info, the last 3 numbers on the belt are the length, check your old belt this way and match it up.

Just to add to Bob's usual comprehensive info, the last 3 numbers on the belt are the length, check your old belt this way and match it up.

That depends Shep. If he has the original GM OEM serpentine drive belt or an aftermarket other than like the Goodyear Gatorback or AC Delco branded he probably won't be able to tell or go by that.

For example an original GM belt never replaced may be marked like this:

GM 24506524 SGR 6PK2327 EB


BTW - Here's the part number breakdown of a GoodYear Poly-V belt:

Functional Part Number Gives You The Size Of The Belt

EXAMPLE:

4 06 049 5

1st digit (4) represents a K section Poly V-belt.

2nd and 3rd digit gives the number of ribs.

4th, 5th, and 6th digit are the length in inches.

7th digit is tenth of an inch.

Part number 4060495 would be a K section Poly-V belt, six ribs wide, with a length of 49 and 5/10 inches.

Thanks, The old one was a 93 1/2 and for some reason it just slipped right off the tensioner and pulleys. Could it possibly have stretched somehow. I know the tensioner is good because I replaced it last year and everything else is tight.

That depends Shep. If he has the original GM OEM serpentine drive belt or an aftermarket other than like the Goodyear Gatorback or AC Delco branded he probably won't be able to tell or go by that.

For example an original GM belt never replaced may be marked like this:

GM 24506524 SGR 6PK2327 EB


BTW - Here's the part number breakdown of a GoodYear Poly-V belt:

Functional Part Number Gives You The Size Of The Belt

EXAMPLE:

4 06 049 5

1st digit (4) represents a K section Poly V-belt.

2nd and 3rd digit gives the number of ribs.

4th, 5th, and 6th digit are the length in inches.

7th digit is tenth of an inch.

Part number 4060495 would be a K section Poly-V belt, six ribs wide, with a length of 49 and 5/10 inches.
Bob a lot of the oe belts I see have the oe mfg part number then the actual mfg of the belt has their number which translates to the size, but I may be seeing other than GM belts here, memory is some what less than perfect these days. Shep

Thanks, The old one was a 93 1/2 and for some reason it just slipped right off the tensioner and pulleys. Could it possibly have stretched somehow. I know the tensioner is good because I replaced it last year and everything else is tight.

When you get the new one it should feel tighter. The belts stretches over time and also develops those cracks along the inside. You might consider just using a GoodYear Gatorback. Excellent drive belt. Good luck.

Bob a lot of the oe belts I see have the oe mfg part number then the actual mfg of the belt has their number which translates to the size, but I may be seeing other than GM belts here, memory is some what less than perfect these days. Shep

Alot of variables Shep but if you notice from the info posted on the GoodYear Gatorback belts it is hard to go wrong with that brand and that conforms to what we have been discussing.

Goodyear belts are great. They have a staggered ridge design that does two things. It prevents cracks from developing in a straight line across the belt causing a weak point, and it keeps the belt cooler by increasing surface area. A much improved design over smooth ribbed OEM belts. Nice write-up on the part number breakdown Bob, that should assist those modding their cars with undersize pulleys and such. I sell Goodyear belts where I work, and your breakdown is spot on (of course).