1997 E420 Timing Chain
 

When should you inspect the timing chain on a 1997 E420? I have 175,000 mi. How expensive is it to replace?

Is it making noise? If not, leave it and solve your tranny problem first...

blackmercedes gives good advice, but to add my $0.02, generally speaking M119 engines don't seem to suffer the same chain wear that M117 / M116's do. Maybe it's because the chain tensioner in 119's does a better job. In any event, you might look at replacing the plastic rail guides and tensioner rail first.

Thanks for the replies. I am not hearing any noise from the timing chain. Just thinking about preventive maintenance since I have 175,000 on the car and would like to add another 100,000 after installing my re-built trans. I am hearing the job to replace the timing chain is around $3,500. Ouch!

$3,500 for the timing chain on an M119? If that's a real quote, they're taking you for some kinda ride. For that price you could have the timing chain done and both heads freshened as well.

While the dealer does the tranny, have them check the chain for stretch.

What's the service history like? Frequent oil/filter changes really extend the life of the chain. Have them inspect the top guides and think about having them replaced before doing needless work like a top-end overhaul.

A friend, who is a mechanic, is putting the trans back in. Is it much of a job to inspect the top guides and chain for stretch. I use Amsoil in the motor and change every 12,000. I change it more than Amsoil recommends.

Not sure what an M119 is. I have the V8.

Your 4.2L V-8 engine is a DOHC design (last year in the E-Class) that carries the M119 designation. In your car, the actual engine is M119.985.

The M119 is one of the finest MB engines ever made. It's tough as nails and WAY over-engineered for it's power output. MB used it in racing applications at over 1000hp without modifications to the bottom-end. Many tuners would enlarge it (to 6.0 or more) and stress it to 500hp, sometimes MUCH more, and again without major modification, and no problems.

Checking the top guides and stretch is a fairly simple job that means popping off the valve covers. Your timing chain should be in good shape with Amsoil and frequent changes.

Is the 420 better than the 430?
 

:confused:

Maybe, maybe not. Steve Brotherton has had some problems in repairing M113 V-8's as they don't seem designed for being repaired, but replaced.

Perhaps it has better emissions, but I'm still not sure what was so wrong with the M119. "If it ain't broken, why fix it...?"

Doesn't it make sense to inspect the timing chain with 175,000 on the car even though it is not making noise?

Yes. Have it checked.