Thread: 4bd1 n/a fan belt woes.

Manufactures of Vee belts use their own part numbers, even though they are interchangeable with belts from another manufacturer.

Usually the first part of the number can be decoded into the section size, such as 'A' or 'B' section, or width in mm. If you check the width of your existing belt, or pulley, it is easy to determine if it is an 'A' or 'B' section ('B' is larger than 'A'). There are many other section sizes, but I would wager 'A' or 'B' (my 4BD1T from an Isuzu truck uses a 'B' section fan belt.

Usually the second part of the number can be decoded into the circumferential length of the belt in either inches, cm, or mm. The adjustment for setting the belt tension will accommodate minor differences in length. If you measure the length of your existing belt you then have all of the information you need.

Someone gave an Isuzu part number, there may have also been a Land Rover part number given in one post, the other part numbers seem to be those of the belt manufacturer. The different number system doesn't necessarily mean they aren't interchangeable.

I would never buy from either Isuzu or Land Rover, given their mark up, but from someone who sells transmission equipment, such as many bearing sales places. Good brands are Gates and Diamond, but there are plenty of others.