I am getting some slight valve ticking - '90 420SEL. There is a tappet that sometimes does not pump up at start up but after a second or so is fine. The noise is not horrible or related to the start up noise. It is on the passenger side of the engine. There appears to be minimum cam wear on the lobes.
My question is what type of oil can I use to minimize the ticking (weight, not brand)? I am currently using Mobil 1 10W-30 (yes, I know it is not MB approved but didn't at the time I changed my oil about 3,000 miles ago). I have 5 qts. of Mobile 1 15W-50 to use with my next oil change.
Should I go ahead and replace the tappets (hydraulic compensators)? I have not been able to determine which one(s) are making the noise.

If the noise is only on start up and then the lifter fills and pumps up then I would not bother to do anything about it, if it was my car and I did have a lifter that was making noise on my 300E that would tap tap tap after an hour of driving or so. I changed to REDLINE synthetic 20/50 oil a few months ago and the noise disappeared and has not returned ! for your vehicle I would recommend doing the same, I prefer REDLINE over the Mobil 1 brand as that is what was in the car and the lifters were noisy. Consider adding Marvel Mystery Oil to the crankcase for a few hundred miles prior to changing out oil.

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Jerry

2004 SL500 Black 55K Miles
2002 s500 Black 90K Miles
1986 300E Gold 233K Miles
1966 Twin Cessna 320D
1989 Jeep Cherokee 233K Miles
1994 Ford Van E150 399K Miles

I agree it is nothing to obsess about, but it is not 'korrect.'

Did the tick start after you filled with Mobil 1? If it was there before, due to varnish in the compensator, the Mobil 1 itself might help clean out the compensator.

If it started with the Mobil 1, it might go away when you go back to your usual oil.

If it gets worse, as in it does not stop after a few seconds, you will then need to consider replacing it.

Oh, if I recall, your 420SEL is an 8 quart change, so you'll need 3 more quarts of your Mobil 1 15W-50.

Best Regards,
Jim

When I first got the car it was a lot worse. The first oil change I did I used an engine flush and then Mobil 1. It was quieter immediately but was about as it is now. Do you think the heavier weight oil will lessen the noise?
As before, it is not getting any worse - just somewhat annoying. I do not think it is a dirty compensator - just typical valvetrain noise.

I like what I read about REDLINE and the formula and chemistry,

http://www.redlineoil.com/products_motoroil.asp?productID=45&synthFlash=1&subcatID=14

seems to have larger molecules that do not breakdown, I believe that is what got rid of my noise, I don't like engine flushes, you never know what they remove that was holding something together and then where it lodges, Change to REDLINE is a cheap try. Let us know results

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Jerry

2004 SL500 Black 55K Miles
2002 s500 Black 90K Miles
1986 300E Gold 233K Miles
1966 Twin Cessna 320D
1989 Jeep Cherokee 233K Miles
1994 Ford Van E150 399K Miles

I Would Like To Try The Red Line Products, But In Houston, The Oil Is $10.00 A Quart. Thats 2 1/2 Mobil One Changes.

Yes the heavier oil will eliminate the noise, I had the same tick sound in the morning, I switched from 10-40W to 20-50W Dino oil and it is quiter in the first start ups in the mornings.

HTH

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87 420 SEL
Looking for a nice mid 80's MB diesel.
87 BMW 528e (Sold)
99 TOYOTA 4Runner
1989 Honda Accord (Sold)
1988 Honda Accord (Total)

Just a theoretical thought: if the noise is caused by the lifter not pumping up fully, one would think that thinner oil would be better, since it has a better chance of flowing into the tiny oil passageway that 'fills' the lifter. However, since any oil will be pumped under pressure into the lifter when the engine oil pump spins, the thicker oil would 'drain down' more slowly on shut-down, and hence it would take much less to fill it/pressure it up on start-up. The lifter problem is thus often fixed by an initial flushing of the passageway (engine flush, Marvel, thinner oil or whatever), then maintained by using a heavier weight oil. Of course, sometimes the lifter is defective (lost it's ability to seal and hold pressure, or bore is permanently plugged) and needs to be replaced.

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1986 560SL
2002 Toyota Camry
1993 Lexus