timing chain service interval - when should i change it?

[james watson]

does any one know how long the cambelt chain inside the engine lasts on a 91 260e? some people say you should change them every 100,000 miles,and others say they last forever.whats the definitive answer as there is nothing mentioned in the owners manual.
thanks

 

[Will]

timing chain service interval

James,
I don't know that there is a definitive answer to your question, but there are at least three or four ways to decide if its time for a new timing chain.
1. Mileage. 100,000 is reasonable as you said.
2. Chain stretch. See if timing marks on cam and head line-up.
3. Visual inspection. Wear in teeth, tensioner, and chain.
4. Sleep test. If you can sleep at night!!
Take it to your local garage and get them to check it over if you are worried about it.

Regards,
Dave