If you have replaced you serpentine belt, your experinced advice is requested and would be appreciated!

I have an 03 MCS.....So I replaced my OEM belt this weekend. But, here is the issue. The new belt, Which is oem and the same part number as the old belt was actually a bit longer than the original worn out belt with 6yrs/60k miles.

Before removing the old belt I noted that the tensioner position was half way between the first and the second hole. After installation of the new belt, The tensioner position is covering about 1/3rd of the first hole now. From what I have read, this is usually the position of a worn belt that is ready to be replaced, but this is a brand new OEM belt. I have double checked routing and drove the car just fine.

Should I get new belt? Is this okay? When this belt wears will the tensioner run out of travel?

 

How do you know the belts are the same part number? Comparing numbers on the belts themselves?

 

yes, I could barely read the number on the old belt, but was able to make out the same part number.

 

Quite odd... personally, if I didn't have a full hole showing, I'd want a shorter belt to ensure there was no slippage. But you may be fine with what you have.

You may want to replace the tensioner assembly as well.. they are failure prone, and quite a few folks replace them preventatively every 50,000 miles or so because failures can leave you stranded... I don't expect that this would impact what you're seeing with belt length, though.

 

that tensioner assy is not something I am want to replace. From what I have read it seems the tensioner itself is something that is not really supposed to be a wear item. Meaning it fails prematurely or doesn't fail at all.

The tensioner is working fine right now, but im wondering if I got a bad belt or something.

 

Are the belts from the same manufacturer? I've found some variance in size going from one brand to another.

 

Both belts are oem mfg. New belt was purchased from MINI dealer. Ironicaly the reason I like to stick with oem parts is to avoid this sort of inconsistency. As an engineer, I prefer to fit parts that function just as the original engineer intended. It makes me a bit nervous that this new belt seemed so different in size. But this is the only belt I have replaced on a MINI. I don't know whether this much variation is to be expected or is unusual. I am hoping some one who has replaced a few can shed some light.