MINI N18 Engine: Timing Chain Guide Failure. Is this the return of Death Rattle?

When BMW Mini introduced the N18 engine in 2010, we all breathed a sigh of relief.

It’s forerunner, the N14 engine, was notoriously prone to timing chain tensioner failures. So much so that, at one point, our workshop had four Minis lined up for replacement timing chains – and we had four customers with costly repair bills.

So when the eagerly awaited, and much improved, next-generation engine was launched we all began to relax. At last, an end to the dreaded words "N14 death rattle". 

It seems, however, that we may have relaxed a little too soon...

Lately we've been seeing a noticeable increase in (yep, you guessed it) timing chain failures, this time on the N18 engine. The cars aren’t quite queuing up again just yet, but it’s certainly enough to invoke a mild sense of déjà vu.

What’s the cause?

The root of the problem is usually the top timing chain guide snapping at its mounting point. After bouncing around against the chain and the cam lobes for a while, it either jams in the chain or – worse – breaks apart, sending debris around the engine. Some of the fragments can lodge themselves in the oil pump.

What’s the fix?

Without the top timing chain guide in place, the loose timing chain quickly becomes stretched. This leads to the timing between the camshaft(s) and the crankshaft becoming out of sync.

When that happens best practice is to replace the timing chain, chain gears, side guides, tensioner and top guide - with the very latest versions available from BMW Mini.

Depending on the technician’s observations, a replacement oil pump might also be recommended as there may be bits of swarf from the snapped guide's support lodged in the oil pump.

What to look out for

There are a number of potential issues with timing chain failures, but some of the key symptoms can be: poor performance; misfiring or hesitation; a loud rattling noise; engine warning lights coming on; and the vehicle going into limp mode.

We’re keeping our fingers crossed the “death rattle” isn’t making a comeback, but if you’re concerned about your vehicle you can book a diagnostic appointment online or by getting in touch.