Back ground:
Bought '79 300sd six months ago. Been averaging 400 miles/week. I've been working my way through routine maintenace and replacing parts as needed. When I bought it, I asked when were the valves last adjusted..."It's been a while". It's been a little hard to start in the mornings (80 F here in Texas) and idles a little poorly. Pickup isn't as good as it used to be. Recently I ran a quart of Diesel clean through it over the course of 1-1/2 tanks while driving in the Italian tune up style, then changed the oil and both fuel filters.
So it's time for the valve adjustment (next will probably be injector maintenance).
I've ordered the three funny looking Hazet Wrenches. I've got a new valve cover gasket, some high temp rtv, a feeler gauge, map of which valve are intake and which are export, and the usual hand tools and shop supplies.
I'm planning to hit it hard Saturday morning. Any last minute tips or advice?
Thanks
J

What do you plan to do with the "high temp rtv"? Clean the surfaces and just use the gasket - make sure it seats before tightening.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html

Have fun - don't cross thread the valve cover nut like I did a couple of weeks ago!

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Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

So you're saying not to use gasket sealer with the valve cover gasket?

Yep, no need for RTV on the valve cover gasket.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

I use a THIN film of wheel bearing grease on my VC gaskets when I do 'em.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

I use (RTV) silicone sealant on my valve cover gasket.
I degrease the area where the valve cover gasket contacts and about 1/4 inch above that on the valve cover itself with brake cleaner
I put bead of silicone sealant all the way around the inside groove of the valve cover gasket (this will glue it to the valve cover as well as seal).
I spray some brake cleaner on a clean rag and degrease the contact edge of the valve cover gasket; after which I put a very thin coat on silicon sealant on the bottom edge of the valve cover gasket.
I install the cover and tighten the valve cover nuts firm but not tight. I let the silicone dry for several hours and I tighten the valve cover for good.
Every time I remove the valve cover I rub off the outer layer of silicone sealant and renew the silicone sealant be for reinstalling the valve cover.
The result is I have no leaks in the 5 times I have had the valve cover on and off and I am still using the same valve cover gasket. The gasket remains glued to the valve cover.
I took me almost as long to write this as it dose to put the silicone on the valve cover.

Sure the gasket is supposed to seal with out sealant; but if not you will be doing the job twice and getting your engine messy.

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84 300D, 82 Volvo 244Gl Diesel

I've reused the same VC gasket at least 5 times w/o sealant and no leaks.

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For Sale: 1982 MB 300TD
1995 Chevrolet Suburban 6.5TD

Sold: 1980 IH Scout Traveler- Nissan SD33T Diesel

RTV should never be used on the engine.

I'm on my 3rd reuse without RTV or leaks.

X2. The gaskets will seal just fine without it and you can reuse it as many times as the rubber stays flexible...probably 5-10 years under normal use. The reason they don't want you to use sealants is because if bits of it break off it can clog up the oil passages in the engine and cause far more serious problems than it solves.

You can use some grease on the edge to hold the gasket on the VC if you find it wants to flop off, but avoid anything like silicone or RTV.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I did valve adjustments on my 616 and 617, reusing the gasket and not putting anything on them. The gasket on the 617 is about three years old. The one on the 616 was on there when I bought the car in '06. Neither one leaks.

I also just pulled the valve cover off my M130 to get the carbs off and will be doing a valve adjust while I'm at it. The gasket is kind of hard (age unknown) and was leaking before, so I'll try to pick one up locally while I'm rebuilding the carbs.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Go to Dieselgiant.com under Mercedes maintenance page(valve ajustment)and it will tell you step by step how to ajust the valves. Saved me a lot of time. 1hr start to finish my first time. Made my own wrenches, new gasket no leaks no rtv