M113 Lifter Noise?
 

I have a 2004 E500 4-matic wagon with roughly 120,000 on the odometer. It runs incredibly smooth and starts easy like it should. However, it produces a noise that is certainly not typical or characteristic; it has a tapping sound, almost like a quiet diesel. I took a video: https://www.youtube.com/watch?v=h1QA3LKQaL8

I read that the M113 'E50' 5.0L V8's have a recurring problem with lifter clatter. I suspect one of the lifters has gone bad, reuslting in this sound... any thoughts?

-As a sidenote, I did take the accessory belt off and ran the engine briefly and the noise is still there-

jcoop, sounds like hydraulic lifter(s) tapping. What is the service history of oil changes and brand, oil viscosity. Check the Owner's Manual, but that engine should probably be running Mobil 1 0W40 oil with changes at least every 10,000 miles. I use Mobil 1 religiously and perform oil changes every 7,500 miles on our MB vehicles.

Thank you for the info. Unfortunately, I don't have much when it comes to service records... I bought the car wrecked at an auction. However, it's extremely clean inside and out and someone had just put brand new tires, rotors and pads on it before the accident. The engine bay is also fairly clean so I have reason to believe it was maintained well. There is an unopened quart of Mobil 1 5W-30 full syn. in the storage compartment behind the back seat, so that's possibly what this car has in it? I have read that these V8's require 0W-40 or 5W-40. I did take the oil filter out of the car and cut it open to look for any metallic bits and it was clean as a whistle -- upon doing so, I noticed that it was a genuine M-B filter and that the oil in the car didn't look that old... ah I love the mystery of a car I know nothing about, haha!

thats a lash adjuster and this problem is a plague on the M112 and M113 engines. They are available separately as spare parts but take some time and a pulling jig to repair as most of the times the upper tube that carries the arms gets plugged with RTV worms which then causes a lifter to suffer from no oil.

Thank you so much for the information. A couple of questions; is there a write-up that you know of that outlines the procedure to change the bad lifter and is there a good way to clear out any RTV that may be starving said lifter(s)? I could probably do the job without any aid from a tutorial, but I just want to make sure it's done right.