what are some key signs that service needs to happen ??

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1983 Mercedes Benz 300CD
-Teal, Turbo Deisel
-daily driver
-pretty slow

2001 Corvette Z06- TOTALLED ! ! ! no mas/gone/adios/see ya
-Speedway White (1 of 352 made/2001 year color only!!)
-weekend warrior car -she is NOT stock
-SUPER fast

I also wonder...

What are some signs that I should do valve adjustment. The thing is that my car runs so well and makes really good power that I wonder if I really need to get them adjusted.
The valve cover gasket does not leak at all though so I'm thinking that it had been done and it looks pretty new.

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2008 BMW 335i Coupe

I am about half ashamed to admit it, but I have gone well over 100,000 miles without adjusting valves on a 616 engine. MB says 15,000 miles, but I went 380,000 on my '84 Euro 240D with only two or three adjustments.

This may not be very representative, because the car was on the road a minimum of 1 1/2 hours at a time, often 6 or 8 hours at a time with very frequent, thorough oil and filter changes. It could be that an engine that gets more warm up/cool down cycles would need this done more often.

If the car is new to you and you don't know its history it might be a good idea to adjust them. Once you know they're adjusted right, then if it gets hard to start, doesn't sound right or run right, pull off the cover and run 'em down.

It's not really a big deal to do them, it's just that in that period of my life I was covering three states mostly by car, raising kids, keeping up my place, etc., etc. and never had much time for anything. I don't log miles on one of these engines any more, but I do have more time on my hands. When I get my 240D back on the road, I plan to be more dilligent in this area.

Good luck,

My 1977 300D has approx 193,000 on it, a relative baby. My dad was religious with oil changes, but only adjusted the valves 'a few times".

I didn't notice any of the negative symptoms, but I did have the valves adjusted after I had put 5-6,000 miles on the car. I did notice a reduction in noise, quicker starts, better pick-up. I also changed fuel filters just after I had the valves adjusted and between the valve adjustment and the fuel filter change out, performance really improved, pick-up/top speed. (for a non-turbo, "really improved" means from very slow pick-up to slow pick-up and top speed from 75 to at least 85 mph.

My plan is to have it done annually by a tech, and have him check out the timing chain (original) as well. I do DIY for most stuff, but would rather have a tech tackle these issues. For $120, it's a bargain.

I'd say if you don't know the history, have it done or do it yourself. It's not a big price tag, even if you have a tech do it and you'll notice the difference.

JCD

There are only 2 signals for an impending valve adjustment:

1. you don't know when last adjustment was performed

2. last adjustment was more than 15K miles ago

BTW, the adjustment won't give awesome performance boost anymore than disabling EGR will. But, much like the disabling of the EGR, the results of consistent valve adjustments are cummulative and will give you an engine that lasts longer and is stronger than it would have been without the service. So, if your car went strong for 100K or 300K miles without valve adjustments, it doesn't mean that the rest of us are chasing our tails performing the regular service. It just means that your car would have gone longer and stronger with the service.

First sign of valves needing adjustment would be hard starting. Just a little compression loss at cranking speed will mean a big reduction in the compressed air temperature that would cause starting to be more difficult.

One way to find out for sure is to measure the valve clearance. If it is within spec, that valve does not need adjustment. Then check them all and adjust as necessary.

Last time I checked the valves after 25,000 miles in my '79 300SD none of the valves needed adjustment. So I am suspicious that the MB spec of valve adjustment at 15,000 miles is valid.

P E H

Valve cover gaskets are cheap and it is so easy to check the clearances so why not check every 15K? RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

hhhmm my car cranks instantly after the pre-glow light goes off (well after I crank it that is.. doesn't really crank by itself :p ) even when it's 20-25F out.. (coldest it's been here).. idles low then a few secs of fast idle it is smooth .

I think I'll get my valves adjusted then. Maybe I'll have the timing chain stretch checked and replace the t-chain as needed + have the injection pump start of delivery adjusted too. Should be a good spring tune up.. oh a new oil filter and Delvac one oil

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2008 BMW 335i Coupe

When I bought my car last Feb , I checked the valve clearance and all of them were tight / closed and the car started up everytime like that and ran smooth like this, also with 223,000 miles on it . There is know record of anyone ever having them adjusted. So after I adjusted them it still ran the same . But the oil and filter were always changed on time , and most all of the normal maintance was carried out during its lifetime. Since I have had it I have gone over almost every little thing . I have 241,000 miles on it now and I will check them in a month or two just to see if they have changed, this way I can determine how long for the next time . I always change oil and filter every 4000 miles anyway.

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A couple of Ford pickups F 150,250, 350 missed.
1983 240 D 256,000 miles ,auto, ac.

Holson.

Almost all the MB crank instantly after the key is turned. The question is how quick they start after cranking starts.

You crank your Mercedes? Like a model T ford? You must have a very old Mercedes, I haven't seen many with cranks sticking out the front of them lately.

Just a suggestion to ask you to be more technically accurate with your replies.

P E H

I had it done because I had no idea of the history. It ran fine before so I had no indication. I did notice a marked improvement overall after though. I also sleep better knowing that the timing chain is nice and tight. Well worth the $75 he charged me.

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1982 300D Turbo "Helga"
380,000 miles

Merriam-Webster Dictionary
m-w.com

Main Entry: crank
Date: 1592
intransitive senses
1 : to move with a winding course : ZIGZAG
2 a : to turn a crank b : to get started by or as if by the turning of a crank c : to gain speed, momentum, or intensity -- usually used with up
transitive senses
1 : to move or operate by or as if by a crank
2 a : to cause to start (as an automobile) b : to rotate the shaft (as a crankshaft ) of especially with a starter c : to use in trying to start an engine
3 a : to start as if by use of a crank -- usually used with up b : TURN UP 2 -- usually used with up

thanks for the heads up, bill.

am now placing dictionary back on shelf, next to flamethrower.

Hi all ,
I have heard about valves and adjustments and clearances and all.

As a novice that i am, can i know what the i need to do to work on the valves , because i feel my car is doing hard start because of the valves.
How do i adjust the valves, how do i measure the clearances . some body here said it is very easy so how do i do it by myself.

thanks,

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1986 230E (revisions on the way)

"Very easy" is a relative term. To me it is very easy as I have years of experience working on cars, trucks, motorcycles, boats, etc. and I have a large well stocked tool chest to work from and the heated garage to perform the job in. To someone else it may not be so, they may not have the tools, time or space to do the job. If you have adjusted valves before it is nothing new. If you have some experience working on cars, etc. and would feel completely comfortable swapping a carburator on an old V8 I would say you can do it. Even if you don't, get the manual and a service CD and study the job, get the tools and give it a try. Or pay a good mech to take care of it. No shame in that. If I didn't have a garage to work in in the middle of winter I wouldn't even think about it. RT

__________________
When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K