Freightliner 6.7 Cummins ISB Belt Diagram (Routing)
It may seem like a unique part to use to make engines go but without a belt, your RV is not going very far. Just like a person who is wearing oversized pants. They are not going very far either without a belt. Belts may be small but they are vital to all vehicles.
While the belt is one of the most important parts of a Cummins 6.7 engine, it is named after snakes. The word serpentine is placed on the belt because of the way it snakes around the components on the front of the engine. You can see a diagram at this link.
To learn more about this belt and how it is supposed to look just continue to read our article. It has the information you want to know about so you can handle any belt repairs yourself. Take a few minutes to see how this information can help you make this repair.
Cummins ISB 6.7 Belt Routing
The routing goes like this:
1. Idler pulley
2. Accessory belt drive
3. Power steering pulley
4. Radiator fan pulley
5. crankshaft pulley
6. Air conditioning compressor pump pulley
7. Accessory drive tensioner
8. Generator
To replace the belt, you need to follow the diagram closely. One misstep and you will have to do it all over again. Once you have the belt in position double-check your work to make sure you got it right. Then tighten the belt up so it does not go anywhere or have too much slack in it.
Once you are satisfied with the routing, tighten it up but do not over-tighten it. Too much tension and you could snap the belt again and repeat your work.
Repairing The Belt
It won’t be hard to know when it is time to tighten or change the belt. There are signs the belt gives off letting you know what is going on under the hood. You will hear either a chirping sound or a squealing noise when the belt starts to wear out.
The first few times you hear these noises, you can tighten the belt and stop the noise. But you can only tighten so far and when you come to the end of that extension, you will need to find a new belt and replace the old one.
Sometimes, the belt won’t make any noise but will still be wearing out on you. A visual inspection will help find cracks, uneven wear, damaged ribs, and more. Also, test the tension by pressing your finger on the belt. Just make sure the engine is turned off when you do this step.
Belts are not usually that expensive, but this may be an exception to the rule as it is longer than many other belts and made for an engine meant to power heavier and larger vehicles.
Also, belts should not be that hard to find. There are many auto parts and other RV outlets that carry quite a few in stock. You just have to find the one closest to you with the right sales price.
Cummins ISB 6.7 Belt Tensioner
This is supposed to be an automatic functioning engine part. Its job is to keep the belt at the right tension all the time. very few bolts are needed to hold it in place and its location is roughly the middle of the outside front of the engine.
If you need a part number it is 3104029 or there may be another part number or two. We have seen at least four so far. Take that number with you when you go to the auto or RV parts outlets to find a replacement.
Usually, you should get 6 months to a year warranty but that will be up to the dealer you buy from. Unfortunately, Cummins has moved its manufacturing of this part overseas to China but the part is built to Cummins’ specs.
The good news is that this part is widely available and you can find a parts supplier near you with a quick tensioner search.
Belt Issues
Do not be quick to conclude that the component that is not working has failed you. Many failed parts do so because the source of the problem is the belt. The two most common parts that this situation occurs are the power steering pulley and the air conditioner system.
When you lose either, most likely it is the belt that has gone bad and not the more expensive parts. If the belt breaks then you are not going anywhere and all components will stop functioning.
A check engine light may light up to alert you of a belt problem. Or you may see some error codes alerting you to a possible problem. To avoid these situations, you should replace the belt before it is worn out.
Freightliner Cummins 6.7 Belt Diagram
This diagram is very simple and the reason for that is that the belt routing is very simple. Just follow the picture and you should be able to put a new belt on in no time. Just make sure you know which bolt to loosen to loosen the belt tension.
The top picture comes without #8 but you can find what part that is above in a previous section. The lower image is just to give you a different view.
Some Final Words
When it comes right down to it, the belt is one of the easier parts of the engine to replace. It just takes one bolt to be loosened and then you just pull it off. When that is done, you place the new belt in its place making sure to follow the correct routing.
After that is done, you tighten the bolt back up and go on your way. If you do not have a bolt handy, sometimes a pair of nylons will work temporarily, if they are long enough.
