[Wood Gnome]

Hi everyone, apologies if this subject already has existing threads but I would welcome some advice........... my son has a 2007 320i SE petrol convertible with approx 81k on the clock, the engine has up until recently been very quiet on idle but has been progressively getting noisier and noisier and now sounds like a diesel, there is also the occasional momentary blip on idle when it appears not to fire but then picks up and runs normally but noisy.
Being from a generation when engines could be worked on without a degree in electronics and when things such as push rods, rocker arms and tappets existed, before the heady days of overhead cams !!!! ..........I have learnt to accept I cannot keep pace with the everchanging technology of todays engines.

I have been advised by a local garage that there is little that can be done to restore the engine back to its silent running mode without commiting to significant expenditure. Am I being told the truth or a string of porkies to entice me into spending money ???? opinions and advice please, thanks

[Aragorn30d]

Despite all the modern guff, an engine is still an engine!

Without hearing it its hard to say. Much of the clatter from a diesel is the high pressure fuel injectors, and DI petrols have similar injectors to a diesel engine, so it might follow that its an injector issue?

[Phil325i]

OP it might be your son's engine is covered by a recall on rattling timing chains. Worth asking at your local BMW dealer - hand them the key and they can plug it onto a device which shows which recalls and service updates apply and which have been done.

[bishbosh]

It might also be worth finding an independent garage to get any fault codes read. A BMW dealer can do this but would cost more. This may help narrow down what could be causing the poor idle.

[Wood Gnome]

Thanks for all responses so far, will run the key into our BMW dealer up the road.

Sadly there are no fault codes showing so its all a guessing game... even the local garage I took it to for their ideas thought it was a diesel when I first pulled into their forecourt ????

[old grey steve]

Fault code or lack of doesn't mean to say that there isn't a issue, Judging by your comments tensioners a good place to start inexpensive plus don't take that long to fix, but if the issues gone a little too far then other things on these can take place.

Guides can start to seperate or fracture as you can see below



worse of all these engine can if oil services go say 2 years 18k or so between services get noisy

Here's one we saw earlier this year and this had just over 34k from memory as you can see when we removed the rocker cover to prove a theory we were met with this heavily contaminated head assembly and I do mean heavily contaminated as you can see.




Tensioners on these cars can start to fail and its fairly regular, in fact for around £37+VAT and a bit of labour its a worthwhile service item IMO, loads of places don't bother we listen check and often recommend these are replaced for peace of mind if nothing else again below another 320i cover off look at the chain, hopefully you can see its a little wavey



and when you get cam/crank corrolation issue most think you replace a cam sensor on these. Trust me go searching for this too