OVERKILL
$100 Site Donor 2021
One thing I've noticed is that on almost any engine that has had some sort of failure, there is always varnish present. Many will and have argued on this board that varnish is harmless. I'm not so sure about that.
A recent thread on Maxbimmer, where a gentleman's M62 had its timing chain guide shatter had me thinking about this. His engine had some rather significant varnish build-up inside (I'm not posting his pics until he gets back to me and says it is OK) and my theory here is that the varnish causes the hydraulic part of the tensioner to stick, allowing the chain to slap the guide, subsequently breaking it.
There was a thread on M5board last year where somebody had a tensioner fail. Again, significant varnish present.
And of course this brings up many questions with respect to BMW's oil choice, end-user oil choice and the like. There are FAR too many cases of varnished BMW engines to assume that they all were using some sub-par lubricant. This is especially true with M5 owners, most of which use the coveted "TWS".
A quick search of S62 guide replacement yielded these pictures:
That's a Toronto car from what I could tell.
An M62:
This supercharged car is an exception (it is clean) but he is doing the guides because he had the dealership do them (and he paid 6K) and one of the bolts backed out.... No mention as to why they were replaced initially.
Another S62:
Thoughts?
A recent thread on Maxbimmer, where a gentleman's M62 had its timing chain guide shatter had me thinking about this. His engine had some rather significant varnish build-up inside (I'm not posting his pics until he gets back to me and says it is OK) and my theory here is that the varnish causes the hydraulic part of the tensioner to stick, allowing the chain to slap the guide, subsequently breaking it.
There was a thread on M5board last year where somebody had a tensioner fail. Again, significant varnish present.
And of course this brings up many questions with respect to BMW's oil choice, end-user oil choice and the like. There are FAR too many cases of varnished BMW engines to assume that they all were using some sub-par lubricant. This is especially true with M5 owners, most of which use the coveted "TWS".
A quick search of S62 guide replacement yielded these pictures:
That's a Toronto car from what I could tell.
An M62:
This supercharged car is an exception (it is clean) but he is doing the guides because he had the dealership do them (and he paid 6K) and one of the bolts backed out.... No mention as to why they were replaced initially.
Another S62:
Thoughts?