BMW engines are not famous for reliability and timing chain problems are one of the most common problems facing non M BMWs.

Why do BMWs need the timing chain replacing?

The plastic guides in the timing chain break down and deteriorate over time. This is excentuated with city ‘on and off’ throttle driving. These pieces of plastic in the sump break down and make their way into the oil pickup, causing oil starvation and eventually complete engine failure. This is common to see and needless to say this full rebuild costs a lot more than doing a timing chain preventatively.

How do I know if my timing chain needs replacing?

Have a look over your service history: Even if the chain has been recently done, in the last 70,000 miles or so, it is worth bearing a couple of things in mind.

The quality and brand of the chain used. It is common to see garages charging a flat rate for services such as timing chains… ourselves included! But what you need to bear in mind is that some garages will using the cheapest aftermarket brands available to keep their profits up. We will NEVER do this! We offer full 3 years warranty on timing chain related failure for a reason because we use only the OE supplier.

If your chain has been previously replaced but with an unbranded chain, then it may be worth considering a replacement for peace of mind. Something we commonly see is where garages have merely replaced the timing chains, that had missing pieces of guide, but haven’t dropped the sump to remove these pieces before they block the oil pickup pipe. This is why if we see missing pieces of guide, our technicians will always strongly recommend dropping the sump to remove those remaining pieces. This can cause sudden engine failure when you least expect it and may come as a surprise if the chain has already been replaced.

Something worth noting is that city cars with often lower mileage than motorway cruisers will experience worse wear and often fail at a lower mileage as mentioned above with the on and off throttle driving causing excessive strain on the chain.

Warning lights: Often the first sign that something may be wrong here. Common codes are camshaft and crankshaft codes accompanied under the orange check engine light. If you’re really unlucky you might find an oil pressure code from guide pieces in the oil pickup, or hopefully it’s just a sensor!

Rattling and Rough Running: Chain related or not, it’s always worth attending to your engine when it’s not running well to avoid undue wear and potential damage. Rattling is often a tell tale sign of timing chain looseness.

Visible Looseness: On some petrol engine it’s possible to take off the oil filler cap and whilst the engine is turned off, using a small pick try and wiggle or lift the timing chain. Ideally there should be no movement at all there, if you can move your chain then it’s worth booking in to your garage. For diesel owners, your timing chain is located on the back of the engine by the gearbox. This is why prices for these replacements are more expensive, due to increased labour costs. Unfortunately this visible check method isn’t possible for these N47, N57, B37, B47, B57 engines.

n43 sump pan timing chain guide pieces blockage

timing chain guide slop and looseness movement rattle

Left: Vanos Solenoids covered in swarf from the engine. Not a good sign and should be cleaned off but when this excessive is a sign that there is bad wear in the engine to cause mental shavings like this.

Left Centre: Timing guide pieces caught preventatively in the sump.

Right Centre: Timing chain looseness and excessive play

Right: Missing timing chain guide piece, the sump should be removed if pieces like this are missing

What happens if you ignore timing chain rattle or missing guide pieces?

It will cost you more in the long run! Below is a BMW N20 that suffered oil starvation from guide pieces. This happened as sudden engine failure when driving, car had no warning lights or rattles but has nearly 100,000 miles on the clock. We always recommend replacing chains between 70,000 - 100,000 miles or possibly sooner if you experience any symptoms above or do a lot of city stop start driving.

The pieces you can see here around the oil pump and in the oil strainer are bearing material! This will cost thousands to rebuild, another reason why timing chains should be done early rather than later. The picture on the right shows spun bearings, also known as ‘rod knock’.

n20 engine bearing material engine failure

Here at Element Performance, we know navigating your BMW with all it’s quirks and requirements can be confusing and frustrating so don’t hesitate to give our technicians a call or drop us an email. We are happy to talk you through this and see what your car may need help with. We can be reached on 01845 600105 or info@elementperformance.co.uk or visit our Contact page linked.

Petrol timing chains from: £650 N20 N45 N46 N43

Diesel timing chains from: £950 N47 N57 B37 B47 B57 and many more!

Prices include, OE supplier timing chain and guides with new bolts.

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