Hi, new here and just bought two 300-d's last August, an 81 & an 82. BTW, $1500- & $1400- to purchase.

I try to do my own work when ever possible, such as, water pumps, starters and alts. So I'm a little inclined.

The cold weather has started (+18) and the 81 still starts and runs like a champ w/o being plugged in. The 82 has always run a bit rough, esp. at idle. Now, it won't start at these temps w/o being plugged in. I've changed all the filters, and it didn't seem to cure it, STP diesil treatment seems to help the idle and smoking though. So anyway, I know this car didn't recieve the best care, and I'm sure it hasn't gotten it's valves adjusted since who knows when...

Is there anything I should know or any special tools I should have to do this my self? Better yet, HOW DO I DO IT AT ALL??? I've never worked on the inner compenents before, and I'm not expecting perfection, just a little improvement.

Any pointers would be greatly appreciated...

Thanks, George

BTW, Great site!!!

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81 300-D, 258k
82 300-D Turbo, 178k

George,

The valves adjustment on these cars is simple, but difficult and frustrating to do without the special wrenches. The set is over $50 but you could make a set by buying two cheap, long 14MM open end wrenches and bending them as needed to fit onto the cap and locknut. If you don't have the specs let us know. I know the settings for a non turbo, but I believe your '82 is a turbo car.

You will need to bend these wrenches to match each other, that is lay over the top of each other. They both will look sort of like: _/- with the minus sign higer picking up at the top of the slash. I hope this makes sense and helps.

I have successfully adjusted the valves on a 240D without the wrenches, but it was a big challenge. On a five cylinder, there is a valve at the back that just cannot be done without bent wrenches, it's difficult enough with the wrenches.

Good luck,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

George;

I go with Larry on this one. I just did mine for the first time. I made myself some wrenches by welding two together and then bending them. But I broke mine twice so I will buy the proper ones. It makes the job very easy to do with the proper tools. It never ceases to amaze me how easy these cars are to work on for most things, but, of course most well built machines are.
I believe that the settings are
Exhaust 0.35mm
Intake 0.10mm

Enjoy and just ask if you need more advice. This site is the best there is.

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Mark
82 300SD 100k
91 Caprice SS
92 Jetta TD

I have owned a set of valve adjusting wrenches since 1968. It's been so long ago I don't remember what I paid for them. Whatever it was it has certainly been worth every penny.
I would think BAUM TOOLS UNLIMITED;PO BOX 5856;SARASOTA, FL.34277-5867; Phone number 1-800-848-6657, would have them.
The MB part No. is 621 589 00 01; 621 589 01 01(the 00 01 is shorter in the bend)and 621 589 00 03. They are Chrome-Vanadium and made by Lumens.A good buy. Call them.
Bill Lewallen

Hi guy's,

Thanks for the good info. I've decided to give it a try, so tonight I got the valve cover off. I also started the car for a minute to see the cam and valves at work. I know call me crazy, but it was pretty neat to see. yep, the oil was a little messy, but you only live once...

I'm also changing all the glow plugs and valve cover gasket while I'm in there. I know the glow plug light was very short and was more than likely the snag with the cold morning starts. Besides the plugs themselves, is there any other components I should look out for that would cause the glow plugs to run for only 6-8 seconds?

Thanks again, George



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81 300-D, 258k
82 300-D Turbo, 178k
89 Stang Convert. 178k
99 JP Grd Cherokee Ldo 44k

George,

Actually, on a pin type engine 6 to 8 seconds is about right. The glow plugs can test good with an ohmmeter and still not work well.

If the engine has good compression(for which proper valve adjustment is necessary) and proper timing, a fresh set of glow plugs will many times turn it into a much easier starting engine.

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Hey Larry,

Your right, I replaced all the glow plugs, and the new ones run the same amount of time. I even put the juice to an old one out of the motor to see how they worked, they do work very fast, alot faster than I thought they did.

I've been trying to find the valve wrenches locally, but have had no such luck. I went to two auto parts stores, Sears, MB dealer And asked the "mechanic" (AKA, The Butcher) at work. The "mechanic" at work told me to check a plubing supply house for the wrenchs... So much for getting them quick, it looks as if I'm gonna have to order them...After I check the plubing supply house.


~George~

The special wrenches should be available at parts shop. However, I do it without them and I don't think it is much of a problem. I can't remember having any trouble with adjusting valves on cylinder #5 on a '80 300SD.
I suggest getting gage stock .001" smaller and larger than nominal and use them as go and nogo gages and adjust to the high side (clearance decreases as valves and seats wear). I use .003", .005", .013" and .015" gage stock.
Most important thing is to tighten the lock nut securely. I had a valve go thru a piston because someone didn't tighten the lock nut properly.

P E H

P.E.,

I believe the two 14MM ease the job quite a bit, but I have done it without them more than once.

You are proably right about the next to last valve on the 300SD. The problem in the 123 is hitting the firewall with the wrenches.

Have a great day,