Noisy Engine 7 series - BMW Forum

slurat1958@aol.com · 03-23-2010, 10:27 PM

I have a 1999 740i with 135k miles. When I start up it sometimes has a rattle that gets worse as the engine gets hotter you hear it when it is idling. The sound seems to come from the front at the timing cover. I have read about the vanos unit needing to be replaced on other series but, I have heard mine doesn't have that. If that is the case could it be the timing chain components? Has anyone had this problem with a 7 series? I appreciate any info. Steve:

witeshark · 03-23-2010, 10:34 PM

You may wanna have the timing chain tensioner checked/replaced - and no driving before doing it. If the chain skips time, very bad things!

beamers4life · 03-23-2010, 10:57 PM

yes very bad things is correct talk about possibly bending/ breaking every valve in your motor trust me it take 1/20 of the time to replace a damn timing chain and gears and costs so much less than having to replace your valves and maybe your whole head

slurat1958@aol.com · 03-23-2010, 11:33 PM

Thanks for the advice. I have been thinking that was the problem.

marti5 · 03-25-2010, 06:49 AM

A 1999 740i definitely has Vanos I think yours probably has single Vanos rather than double depends on the date of birth....

kenjh · 03-29-2010, 10:51 PM

what is a vanos??

witeshark · 03-29-2010, 11:10 PM

Vanos is BMW's variable valve timing system.

brettski · 03-30-2010, 04:53 AM

I am pretty sure that the dual Vanos appeared in the 1999 build 740, and is called the M62TU, Marti5 will correct me if I am off the mark.

bricha2 · 04-04-2010, 01:21 PM

I have a 2001 740il and have the same rattling noise when the engine fire up from a cold start. Are there any technical document for a DIY job on replacing the chain and tensioner?

darkhorse737 · 04-04-2010, 06:41 PM

ummm... if i were the car owner:

I would instead take out the serpentine belt and start the engine and check if the sound persists.

at 135,000 miles. it is hardly likely that VANOS or timing chain & auxilliary components are at fault...

the rattle i.e. rapid succession of tick-tick-tick* that increases with RPM's just might be a faulty belt tensioner only

although if & when you listen, it sound like it is coming from the timing cover.

I suggest you eliminate that first, before you suspect more complicated things

basumarra1510 · 04-14-2010, 01:23 PM

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thanks for your information ...........