FSM says to replace manifolt nuts?
 

Was going throught the FSM on reintalling the Intake and exhaust manifolds as I will be doing this tomorrow when my parts get here...

It mentions replacing the nuts that hold the manifolds on.. And when i looked them up from my parts supplier they show 2 different sizes of copper nuts? I searched through all the threads and couldn't find anyone that had mentioned this. As far as i can tell all the studs take the same size nut and the old ones are not copper:confused: I am also missing some of the nuts from whoever took the turbo off the engine at the pnp. Thats why i was thinking of just buying new ones.

Does it look as if the Nuts are actually lock Nuts that are supposed to be used only ounce?
Also the Copper parts place Nuts are the solid Copper or plated?

There is also a type of Lock Nut that looks like a reglar Nut but it has 4 cresent shaped indentations on one side of the nut mid way between the threads and the out side of the Nut. On these the ID is slightly smaller on that end.
There is also a type that has little bumps on each corner of the Nut. In the above cases they are not supposed to be reused.

No they don't look like locking nuts and appear to me regular nuts

I recommend replacing them. I had a bolt break when reinstalling the exhaust manifold on a SEL and it made the job 100% harder.

I found these a some turbo VW site so I guess they do make all Copper Nuts.

These M8-1.25mm Lock Nuts are the same fastener used by hundreds of VW dealers all over the United States. These nuts are the correct 12mm hex design s/copper

those are the ones i found too .... has anyone removed their manifolds and replaced them?

Yes, they are essentially a one time use fastener, only. Taking them off usually smears material around the inside threaded surfaces as it is much softer than the steel stud. They are not anything like "good as new" and are intended to be sacrificial for each assembly. Buy new ones. I get them from the dealer. It is not like you take the manifolds off every Tuesday.

Jim

I was just told on another reputable forum not to use these copper nuts but to just get some 10.9 grade 10 mm nuts and lock washers from the hardware store.

I have removed and replaced the copper nuts on the exhaust manifolds of all 3 of my 190E 2.3-16's most recently. It has been a decade or more since I have done the same on a 240D and if I recall correctly the intake and exhaust manifolds are kind of integrated, so it is possible only the exhaust fasteners would get the copper. Go to the dealer and buy the nuts the car was designed and built at the factory with, which may or may not be copper on your car. I believe the nuts holding the exhaust manifold sections, at least, will be copper. On cars with intake manifolds that are not integral or intermingled with the exhaust manifolds, like the 190E 2.3-16 and the 1998 E300D TurboDiesel engines, the intake manifold fasteners are not copper as they don't see the temperatures of the exhaust and so don't experience the same thermal expansion stress.

I think the factory design and manufacturing data are the most reputable sources. And for the few bucks ten or twelve nuts cost, it sure beats the chance of snapping off a stud, or redoing the job later if you get exhaust leaks.

Jim

Those are for the exhaust downpipe not the manifolds.

That is what i found out just barely on the parts fiche. I will be getting some locking nuts from my Nut and bolt supply house 10.9 grade just like the studs. and copper based high temp anti-seize.

I have pulled quite a few manifolds at PNP, and my own 617 engines. the only copper nuts I have seen are where the down pipe bolts to the turbo. those are 12mm. (wrench) Gear wrench woks good here.
The 2 nuts on the other end of the down pipe for the long bolts might be copper also.

The nuts that hold the intake/exhaust manifolds look just like steel nuts. don`t remember them being any type lock nut. as I remember there is just the nut and a flat washer. there are 7 nuts, and use a 17mm socket.

Charlie

I replaced the manifold gasket on my 1982 300D.

The nuts were not copper. I reused the same nuts with good results.

The manifold gasket has been nicely redesigned and makes a good seal.

At the time, I could not find a torque specification for the manifold nuts.


So there you have it, just another opinion.

Ken300D

Yea, on mine it was just a steel nut and flat washer. I searched high and low, as well, and couldn't find any torque specs. Haynes says "securely".

If you want to know, call Phil at Fastlane. They sell "exhaust nuts" that are copper in two sizes:

http://catalog.peachparts.com/ShopByVehicle.epc?q=1985-Mercedes--Benz-300d-Exhaust&yearid=1985%40%401985&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6193%3AMBC|1504%3AED|10000 135%40%40300D&catid=241035%40%40Exhaust&subcatid=241038@@Exhaust+Nut&mode=PA

I am sure Phil or Roy can give you a definitive answer if these are for the manifold to head joint or the turbocharger joints.

Jim