[WOLFHUNT]

My N20 is at 78000 miles and no timing chain issues. My mechanic says wait until the idiot light goes on. Supposedly you can look into the oil filler and see the chain and the plastic guide-and tell if it's wearing-if you know how to identify that-I don't. He also said if there is a start-up chatter that goes away once warm-that's a telltale sign of a loose timing chain. I read to do the change preemptively, but he warned me away from that due to the expense. My 428i sport line is a manual as well, so I'm just going to wait. Hope for no catastrophe!!!!

[space_2001]

What is the production date of your car?

If it’s before late 2015, I’d just replace the tensioner. The tensioner was updated on later models and is the main culprit for failures.

The N20 and N55 motors have the same design and components for timing with the exception of the tensioner. For whatever reason, BMW decided they wanted a tensioner that had a shorter cylinder.

When the N20 first came out BMW marketing advertised the engines could go 10k to 15k miles before an oil change. This was to appeal to consumers that owning the vehicle wouldn’t be so maintenance intensive. Unfortunately, this led to timing chains prematurely stretching as older and contaminated oil doesn’t lubricate the chain very well. In combination with the shorter tensioner and at some point the chain gets so loose that it eventually either fails or damages the plastic guides.

If the plastic guides break and fall into the oil pan, there is a chance that a piece could get sucked up by the oil pick up. Loosing all oil pressure and destroying it short after.

Fun fact: People often misunderstand that timing chains stretch at the links when in reality it’s at the roller bearings.