Valve adjustment on 617, how often?
 

I just did my valve adjust this weekend. its been about 10K since the last time. there were only 6 out of spec a couple by .002 and a couple by .004. I let the .001 out of spec go since I cant usaully get them perfect anyway. this was about the same as last time. is .002/.004 out on a few valves commen for most people?

10k is a bit soon. I do it every couple years...or every 20k or so....whichever comes first. I'll probably do one on my 300SD soon before it gets too cold....even though it seems to be running/starting perfect as it is.

FSM generally recommends 15k

when mine are really off (from limited experience) they like to be readjusted after 500 miles. Then they stay as expected.


Don't forget turning them causes large variances in tightness.

What is the sympton for lack of valve adjustements?

I have not adjusted my 83 300D for over 27K miles since I had it and do not know when it was last adjusted by the PO. The car still runs smooth and strong. I would like to do it but I just procratinate as there are other pressing issues.

Symptoms do not show right away, but include hard starting in the cold, rough idle, low power, smoking...etc...

27k with no idea of the previous owner's maintenance is way too long. Get on it!

To add to above....When I did my valve adjustment for the first time, I realized it made the engine significantly quieter as well.

DO NOT let your valves go that long, it will cause bad things to happen to your cam.

I do it once a year right about this time. In fact I am due for valve guide seals as well.

If your valves come out of spec frequently it might be a good idead to replaces your nuts (heh).

just bent an exhaust valve...
 

...cuz I went over 15 (think I was at 22K or so). Not fun doing a head removal!

Track your mileage, and stay on the oil changes and valve clearances!

Valve adjustments are not that big of a deal to do.
I use to have VW`s and think they are every 12,000 miles
And my 82 Datsun with the SD-22 Nissan Diesel engine, is every 12,000 mi.

the Datsun and the VW are similar in the adjustments. the mercedes is a little more complicated, but very doable.

The hardest part on the mercedes is getting the valve cover on/off. always
hangs up on something, then the gasket falls off. about the 3rd or 4th time, I win.

Maybe since my timing chain fiasco Iam a little more on edge, checking, and bonding with my baby ;).

Not that big of deal, just do it.

Charlie

I'm excited for the day I adjust my own valves, I need the tools though.. For some reason last time the 220 had 3 tight valves and a loose one :confused:

Unless they're getting noisy or the engine isn't running right, 15K is way too often IMHO. My first 240D, a 77 that I bought new went 280,000 miles and I only adjusted them once. The turbo engines probably need more attention than that, but it's not as if the engine will blow up if the valves are a thousandth or two off.

To echo Larry's experience our '74 240D never had a single valve adjustment in nearly 200K miles of driving as best as I could tell. It was more out of ignorance than neglect. When we bought the car (new in '74) the dealer said, change the oil frequently (every 3K miles) and fuel filters much less frequently and that's all it will ever need and that is all we ever did. In fact, I don't even recall ever changing the fuel filter. Of course now I know better but it goes to show that they can easily go well over 15K miles between adjustments ;)

Realistically, if you did it every 30K it would probably be just fine with one caveat - if you do an adjustment and find the valves to be extremely tight then re-doing it after 500-1000 miles isn't a bad idea - but after that I would still go 30K before checking them again.

I didn't use any "special tools" I did end up grinding down one 14 mm open end wrench a tad, if that now makes it a special tool . . . my 240 only needs a 13 mm to remove the vc nuts, and 2 - 14mm for the valves . . .on the one valve that started to spin, I just held the edge with a screw driver like a wedge while loosening the 14mm's . . .

Just checked the valves on the 300TD- after 25k since the last adjustment, they were all still in spec.

Guess I should be thankful, but the whole process should reward you with a little work at least.

This isn't always the case, however, my old sedan had very tight clearances after 12k.