I have a 1983 300D-T that hasn't had its valves touched in probably over 30K miles. Should I get on it and do it? If so, I'd be doing it myself, so is it a hard job to do? I'm trying to get my fuel economy as high as I can get it and I heard from someone on here that frequent valve adjustments help. Thanks for the advice

Alex

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1983 300D (parked for four years)
2012 VW Sportwagen TDI Manual
2001 Miata SE
1962 Chevrolet Corvair Rampside

Since MB would say that you are way overdue, who am I to argue!

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

I don't know if it is really required every 15kmiles, but I would say that at 30k, you probably need it. I went over 75kmiles on mine, and it could have been a lot more because the previous owner didn't look like the maintenance type...like I am?

I found 3 of the 4 intake valves, which should be set at .004 inches, had absolutely no clearance. All of the exhaust valve were about .004, also way too tight (spec'ed at ..012). The car was having cold starting problems last winter.

The car runs and starts a lot better. Fuel economy went from 25 to 30, and now is running about 32 with the addition of fuel conditioner (power service).

Do a search on valve adjust and you'll find a lot of info.

Joe

The valve adjustment will be due on my 1982 300D in a few months and it will be the first time I've done one on this car (or any other car for that matter). The procedure looks reasonable, and I've got some of the special bent wrenches on the way to help with the task.

I'm wondering if you noticed any change in engine noise, better or worse, more or less, after the adjustment?

Not that it would make any difference in my adjusting the engine to spec, I just wonder if going from "no clearance" to specified clearance would make a valve tapping sound.

Thanks,

Ken

Yes, it'll probably make a slight tapping sound, at least for the first few days or weeks. After that it either goes away or you don't notice it anymore...

- Nathan
'83 240D "Steiner"
'00 New Beetle TDI

I looked under my hood today to take a look and see if I was still in the mood to run that valve adjustment job. Now I'm not sure. What the heck is that contraption sitting on top of my valve cover? It's some black box with throttle linkage (?) attached to it. Once I disassemble that linkage, does it need a lot of fine tuning? Thanks

Alex

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1983 300D (parked for four years)
2012 VW Sportwagen TDI Manual
2001 Miata SE
1962 Chevrolet Corvair Rampside

Those assemblies have to do with the linkage for the cruise control and the mechanical connection between the accelerator pedal and the injection pump. [I had to concentrate very carefully here not to say "gas pedal" and "throttle linkage" ]

I haven't done a valve adjustment yet, but I did go through the linkage assembly, popping off each link and applying some lithium grease for lubrication. This would be a good idea while you are working with these items. When it comes time to actually take the valve cover off, I plan to label all the little linkage pieces, take a few digital pictures, and then remove them. There are so many that I know I couldn't get them back in place from memory.

It looks pretty intimidating at first, but I think you'll be OK if you get organized and take some notes. As far as I can tell, if you put all the links back where they came from, and don't change the adjustment on them (they each have a lock nut and their length can be adjusted by turning one end in/out on the threaded rod) there should be no impact on linkage settings.

Incidently, one of the first things I had to do after getting the car was to replace the part of the linkage that attaches to the firewall. It holds a long rod and acts to convert the pressing of the accelerator pedal to a rotational motion. Mounts to the firewall with two bolts. The OEM piece was made with an inferior plastic that tended to wear and break - the result was the linkage rod would pull away from the firewall. Replacement cost around $45 and is a much better design/construction - and it makes the pedal action much smoother. And no doubt safer.

Be sure to inspect this part of the linkage while you're in the engine compartment. Replacing this and lubricating all the linkage bars really made a difference in the ease and smoothness of the accelerator pedal action.

When you complete the valve adjustment, please report back on what you found in terms of how far (if at all) the valves were off specification.

Ken

I am not proposing that you ignore valve adjustment, but I just wanted to throw something in here.

My 240D original engine went 380,000 reliable miles on maybe four valve adjustments. The engine had ridiculously thorough oil changes, but few valve adjustments. It purred and always started the whole way.

This is one of those things that I offer with embarrassment, but that was my experience. When driving that car, I was driving a lot and buisier than a one armed paper hanger with an itch, so the valves just didn't get the attention that they deserved.

Have a great day,

When I do the valve adjustment on my 240D, I leave most of the linkages intact and attached to the valve cover. When you un-bolt the valve cover from the head, you can just roll it to the right (er, toward the driver's side) and lay it upside down still attached to the accelerator linkage. It's in the way a little bit when you do the valve adjustment but it's not as annoying as trying to disassemble and reassemble the whole job. You still have to disconnect a few pieces but most of it can stay intact.

- Nathan
'83 240D "Steiner"
'00 New Beetle TDI

Larry

I went 75Kmiles plus probably 25 or 50k for a total of 100 to 125kmiles on my valves...I just don't know what the previous owner did. The car would still start easily down to about 20 to 25 degrees but had problems below that, and fuel economy was down about 20%.

I would bet that you can easily go 30kmiles without much of a problem. I tried to get that data from people months ago, but just couldn't get how much each valve had to be adjusted for a given mileage.

I plan on adjusting mine every 2 years (about 28kmiles), and am going to run this car until one of three things occur (1) It has so little compression it won't start at 30 degrees with a block heater, or (2) it blows the engine or the tranny, or (3) it gets Killed in Action.

I'm doing a life test on this baby.

Joe

PS...before you adjust the valves...think about how you're going to turn the crankshaft. That's what caused me the most trouble of all.