I bought an 81 300SD for my daughter as her first car. We are both novices mechanically but we are going to attempt to adjust the valves this weekend. There is currently a clacking noise that seems to be coming from under the valve cover approximately where the Mercedes logo is. It is different than the clicking type sound we hear elsewhere. Is there something we should look for while we have the cover off?

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1981 300SD 214,966 miles and praying

Besides the valve adjustment we are doing this weekend, what else would you advise doing on a newly purchased car? We changed the oil and air filter last weekend. I imagine belts and hoses are in order also, but is there anything that you would automatically do if you don't know the maintenance of the car you just bought?

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1981 300SD 214,966 miles and praying

Hmmm......that is not a good area to hear a clacking sound. That is where your timing chain is located. As you are turning the engine over to do the valve adjustment, I would inspect the the links, sprocket, etc. for anything suspect. If you don't see anything loose, it would be worthwhile to have a professional take a look.

It probably would be a good idea not to drive it until you find out what is the source of the noise, due to its location.

The belts would be good but unless you see a damaged hose, I wouldn't change them. I say this because there have been several people reported that the aftermarket hoses are not near the quality of the original ones. In fact, some have reinstalled the original hoses after noting this.

Fluids will be the main thing. Power steering, differential, transmission & brakes. There is a good DIY section on most of these areas to help you with the procedures. After you read through some of them, the folks here are real helpful about answering any questions that may pop up.

(Once you get this car in prime shape, your daughter may have to keep stealing the keys from you. These cars have been known to be addictive. Enjoy!)

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Sam

84 300SD 350K+ miles ( Blue Belle )

I was afraid of that. I wish I had found this forum while I was looking for a car. I think I made a crappy purchase.

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1981 300SD 214,966 miles and praying

That depends on how much you parted with for it.

The noise needs careful investigation...remover the valve cover ...if it has a cruise control motor next to the front of the valve cover...remove the three ( 10mm size head ) bolts and swing cruise motor away...this will allow you to pull the valve cover of without gymnastics.

Check each cam tower for loose bolts or crack(s)

Check the cam timing...a good indicator of chain stretch.....roll engine to O/T on front crank pulley......notch on cam spacer washer should line up with mark on front cam bearing tower......if it is after the mark there's some chain stretch.....try to roll engine over so cam is now at TDC and then read degrees on crank pulley to determin amount of retard...often up to 9 degrees.

With a wrench on the power steering pump pulley bolt...roll the engine over to check the valve clearences....the gap is posted on a label on the radiator support.

The gaps need to be reasonable close...although 2 to 3 thou off is no disaster as long as that is 2 to 3 bigger.

Search forums for other maintenence...lot's of info' listed by other forum posters...if you get stuck, just post to Tech' forum.





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[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

Whoa! Don't put the cart before the horse. Until you open it up, you wont know what you are dealing with. If it is a timing chain, many folks can walk you through what to do. IIRC, cost is about $100 and a couple of hours. There is a DIY, with excellent photos, on this as well.

The car, with that engine especially, is considered one of the best built cars that Mercedes made. Hang out here and we will help you sort it out.

(I am speaking from experience. When I first bought mine, there were several issues but coming here and doing a lot of reading sorted most of them out.)

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Sam

84 300SD 350K+ miles ( Blue Belle )

This is the first car I've ever owned that doesn't have a carburator and I sometimes feel I like you speak a different language on this forum. Never having even riden in a Mercedes, I fell in love with this car after the first test drive and lost any objectivity I may have had. I am going to do the valve adjustment and look around like the previous post pointed out, then take it to a qualified mechanic and have them do a checkup on it. It seems to run great. Way more power than I expected after reading some of the posts here. I expected joggers to be passing me as I was accelerating, but I am pleasantly suprised.

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1981 300SD 214,966 miles and praying

The clacking noise is probably 'Nailing". The usual cause is a problem with that cylinders injector. You can check it by loosening the supply line to the cylinder while its running. The idle will get rough but the noise should go away.
It is probably a good idea to do a diesel purge. That usually helps some. If that is not enough you may need new injectors.

While I have your attention. When we changed the oil we got about 4 or 5 quarts out of it, but the dipstick shows full and I added only slightly over 2 quarts. What is the oil capacity for this car? Is it possible I have the wrong dipstick in it? I need a maunual, there are a bunch of DVD manuals on ebay, are they worth the money? I'm in over my head and I've only had the car 2 weeks. I want to drive it everyday now but I know I have to do some work on it.

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1981 300SD 214,966 miles and praying

[QUOTE=SD Blue;1445502]Hmmm......that is not a good area to hear a clacking sound. That is where your timing chain is located. As you are turning the engine over to do the valve adjustment, I would inspect the the links, sprocket, etc. for anything suspect. If you don't see anything loose, it would be worthwhile to have a professional take a look.

I think you got turned around, the logo is at the other end from the timing chain. I'd go with the valve adjustment first and if it still makes the noise then check into the injector nailing. As SD Blue said it is always good to check over the timing chain when you have the valve cover off.
Thats just my $.02

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1983 300SD
200000miles

Thanks Phil, you are correct. I hope Peabody can calm his nerves after I accidently misinformed him.

(Sorry about that senior moment.)

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Sam

84 300SD 350K+ miles ( Blue Belle )

When I got started on my car, the Diesel Giant site was a great help with the initial maintenance issues: http://www.dieselgiant.com/mercedes_diesel_maintenance_tips.htm

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Pictures of the MB: http://s230.photobucket.com/albums/ee41/EricandRobyn/1981%20Mercedes/

1981 300 SD with a Goldenrod water block and Injetor line heaters. EGR is missing

1999 F-350 with HP X-over, Dahl 100 Fuel Filter, Coolant by-pass filter, CCV mod, Tymar intake.

Both on single tank WVO blend

If you only have 2 quarts in it....Don't start it. I'm not sure on the SD's but capacity should be in the 7-8 quart range.....Not 2.

Now relax, there are a lot of minor things to look at that mimic major problems and I feel confident you will discover them without finding "major "problems

@ 200k you are looking at just getting out of the breakin period

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81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

(Sorry about that senior moment.)[/QUOTE]

That makes two of us

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1983 300SD
200000miles

As JackG said DON'T start it with only 2 Qts of oil. I have an 83 300SD and if it is only 1 Qt low it will start making a clacking noise. Make sure you have enough oil in it and the noise may go away. Mine takes between 7 and 8 Qts when I change the oil and filter. If you can't get a good indication with the dip stick I would drain the oil and then put in 7 qts so you are sure how much you have.

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1983 300SD
200000miles