My Turn, Probable TCG Failure 2000 540iT (Long Post)

[scubajim20]

From what I can surmise, I think it's very risky to wait for the symptoms. This should be a pro active repair.

[kouks]

I know this may go against the grain, but the timing guides are designed not to be a catastrophic failure. When the plastic bits fail, the chain will get loose and rattle like the car is a diesel. In some cases (like my own), the plastic bits may wedge themselves on the rail and still provide enough tension on the chain not to create noise. In either case, the chain will not jump timing until the metal parts of the guide are damaged. That will take some time.

The car is drive-able for many miles before that happens. How many...who knows. When they failed on my 740iL I was about 50 miles from home. Kept driving it to the driveway. When I took it apart there was some, but very little damage to the metal parts of the guides. I am NOT RECOMMENDING you continue to drive the car as a daily driver with chain guide failure, but just realize, the M62 is a tank of an engine and there is no immediate need to pull over and get stranded. If you're on a daily commute, just get it home or to your indy (who will most likely refuse to do the job), then park it and fix it. Just don't put much pressure on the engine and it will take you home just fine.

We are all nuts about our cars so preventative maintenance on an M62 with about 150k miles or more is warranted.

[JimLev]

However, the Boom can be significantly delayed by installing a longer spring and replacing the timing chain tensioner. You know, my 50 cents solution...!!
Also, there will be plenty of advance warnings before the actual Boom occurs: bits of broken guides plastic in the oil pan, more pronounced and longer clacking noise on cold startups,...Besides, I understand when the Boom occurs, you can just drive the car or have it towed back to your garage.

So yes I am definitely keeping the 540, but I am really not much concerned about an imminent Boom, yet

The tensioner isn't going to save your butt.
The spring may be a little longer but it isn't as thick as the old shorter one so the tension would probably be about the same, maybe less.
Even if it provided more tension that would equate to more guide wear.
Longer clacking at startup is also a symptom of bad vanos o-rings.
A few years back when I lived south of Boston a buddy that lived near me called me from Hoboken NJ, his engine just started making noise.
He drove it back to MA (~230 mi). I did his guides, the center U guide was completely worn down to the aluminum.
At your mileage Chedley your living on borrowed time, they could last another 5K or 25K. Are you feeling lucky?

I did replace the main chain only because I got a 40% discount on all the parts. I compared the new and old chain, they were the same length.

Tensioner2.JPG

[msvphoto]

I know this may go against the grain, but the timing guides are designed not to be a catastrophic failure. When the plastic bits fail, the chain will get loose and rattle like the car is a diesel. In some cases (like my own), the plastic bits may wedge themselves on the rail and still provide enough tension on the chain not to create noise. In either case, the chain will not jump timing until the metal parts of the guide are damaged. That will take some time.

The car is drive-able for many miles before that happens. How many...who knows. When they failed on my 740iL I was about 50 miles from home. Kept driving it to the driveway. When I took it apart there was some, but very little damage to the metal parts of the guides. I am NOT RECOMMENDING you continue to drive the car as a daily driver with chain guide failure, but just realize, the M62 is a tank of an engine and there is no immediate need to pull over and get stranded. If you're on a daily commute, just get it home or to your indy (who will most likely refuse to do the job), then park it and fix it. Just don't put much pressure on the engine and it will take you home just fine.

We are all nuts about our cars so preventative maintenance on an M62 with about 150k miles or more is warranted.

Good to know. Mine was good for 7 city miles and I feared it would not have gone much farther. I'm not sure what I would have done 50 miles from home when the guides went, probably call AAA for a tow home. Owning (sometimes lots of) old cars dictates a Premier membership with 200 mile tow range.

For those planning to do this job sooner or later anyway, best to do it on your terms rather than let the car dictate when it shall be done. For me the timing wasn't great, but I still got it done eventually. The car told me I had to do it!