🙉 Martynn's Tips: How to Silence Noisy Tappets

From: Haynes - Tuesday Jan 24,2023 12:30 pm

An easy fix for noisy tappets?

My BMW’s engine has always suffered from noisy hydraulic tappets. Not all the time, I grant you, but leave it unused for a few days and on start-up the 3.0-litre straight-six motor sounds like a tractor.

As soon as the engine reaches normal operating temperature and the revs stay above 2000rpm for a few minutes, the noise disappears. If I use the car every day, the noise doesn’t occur at all but, having looked through various BMW forums online, it seems to be a common complaint both here and across the pond.

Initially, BMW issued a TSB (Technical Service Bulletin) on the subject, advising their technicians of a ‘bleeding’ procedure. This involved running the engine at above 2000rpm for 10 minutes or so. Basically, the same thing I’d already done. Which meant the noise returned if the car was left unused for a couple of days.

BMW assured everyone that the noise wouldn’t cause any damage, but still the complaints came. BMW even replaced cylinder heads under warranty in an attempt to cure the problem – successful, but what a cost!

Later TSBs advised changing the exhaust side hydraulic tappets, but the forums are full of various remedies/causes, including using a specific brand/specification of oil. It’s really difficult to know what to do for the best.

The costly option

Changing the exhaust tappets sounds sensible, but each of those is approximately £15. I’ll need 12 of them, plus a new cam cover gasket, and because the engine is equipped with the Valvetronic system, removing the cam cover and exhaust camshaft is not the work of a few minutes.

If I have to change the tappets I will, but first I wanted to try something that would require significantly less work and money…

Tap here to see what cheaper fix worked for Martynn

Technical Editor, Martynn Randall has been with Haynes for 27 years and has written more than 60 Haynes Manuals.

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