M104 sudden lifter(?) noise
 

Literally overnight my 93 300E 2.8 started up with a slight stumble and louding tapping noise. Compression tests OK, stethoscope doesn't identify a real smoking gun, but 5 and 6 exhaust valves seem loud. Bottom end sounds OK. Is it normal for lifters to go out this suddenly or am I chasing the wrong thing?

The lifters or "Elements" usually don't go bad, could be alot of carbon built up or sticking valves.

Does the noise go away in a minute or two?

The first time I noticed it the sound went away after a minute or two. I've started it a few times since and it doesn't go away. I've let it run for as long as 10 minutes while troubleshooting, but probably not to the fully warmed up state.

Bump, my M104 just started doing this after an oil change. I did change oil types but did not expect this to happen. I normally run generic oil, whatever is on sale. Nothing thinner than 10W40 but all the way on up to 20W50. This time I put in DELO 400 which is 15W40 (right in the middle). Car was "normal" for about 10 miles, then it sat about 2 hours. Upon restarting, there is 1 loud lifter; it's pretty pronounced. Drove about 10 miles home and it ticked all the way. Any ideas? I hate to drain the DELO and put generic 10W40 back in there, but I'd rather do that than damage something. That's a lot of $$$ down the drain.

By the way, the M104 has about 185K on it. Ran silky smooth until this oil change. Last oil change had about 5K miles on it. And yes, I already checked the level. It is fine. For reference, I put 7.5 quarts in it during the oil change.

gmercoleza, original factory fill in the 104 engines was 15W40 mineral oil so the Delo 400 should be fine, although I thought Delo was for diesel engines.

FWIW, I run Mobil 1 15W50 in our 104 engines year-round with no problem, and have for the last 10 years. Change oil & filter every 7,500 miles per the Maintenance Booklet.

I have run DELO in all my other Mercedes for the past 12 years. I just hadn't made the switch in the E320 yet. I prefer DELO for its superior detergent qualities and zinc additive lacking in conventional motor oil. I wonder if the detergent broke something loose which is now obstructing an oil passage? I think I will leave it in there for now and see where the ticking goes. One of my 380s ticked like that for 3 years and never got worse. It was just a little annoying.

Well the ticking will go away for quite a while, then come back for a little bit, albeit faintly. It's irregular now, but mostly it doesn't occur and the engine is quiet. I think I'm experiencing the effects of a gentle cleaning. Well if I wasn't sure there was a significant difference between oils before, I sure am now!

I think I will try a run of Delo 400 for my next oil change, right now I am running Mobil 1 0W-40 Euro Formula, but fear the lack of a large zinc additive could be causing extra wear on my M103.

....have a '91 300E that does that all the time near the back towards the firewall. I have no idea why. It's a "tick, tick" sound that comes and goes. I have 186K on the engine.

Steve

Well I drained all the DELO after just a few miles and filled with standard 10W40. You guessed it, no change. I then pulled the oil filter and found it was the culprit. It had come unseated from the housing and went in crooked. There was a dent in it from where it was crammed up against the check valve. I reseated it properly and now the engine is silent again.

I am really upset that I dumped $40 of perfectly good DELO for nothing, but a lesson was learned. NEVER go with cheap STP oil filters from AutoZoo. I normally order my filters from this site, or get them from the dealer, and keep a spare in the trunk, but I ran out and needed one NOW. Next time I'll just wait or drive to the dealer.

guy today same problem

Filled and "prescribed" for all pre-ASSYST gasoline and diesel engines here in Europe is fully synthetic 0W-40, 5W-40 or 5W-40 with the correct MB approval. Practically "nobody" uses mineral oil on any engine anymore.

I think work man pay is higher over there.I've run 15w40 for years when temps are mild.And only syntheic during winter. It a market gimic to covince people to spend more money on these new oils.No one with any brains would let oil stay in a engine 10,000 miles.