so I noticed I have an exhaust leak at that flex coupling. How do you replace that? The exhaust manifold has to come off? Also, the nut circled... only one is there... the other 3 are missing. Anyone know the nut size? It's like every time I open the hood something else is broken lol

Eventually they all break. Looks like there are only 2 nuts and two bolts needed.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Sorry I wasn't clear. I'm trying to find these nuts. I only have one out of 4.



Also, I assume I have to take the manifold off to replace that flex coupling? I couldn't find any tutorials regarding it.

What is the year model and engine of your car or vehicle?

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84 300D, 82 Volvo 244Gl Diesel

That looks like an OM603
It would be less work to remove the rear section of exhaust manifold than the front piece which is attached to the intake feed, wastegate pod and block and has some really hard to access nuts and bolts.

As to the nut, IIRC it is an M10, possibly and M13, should not be difficult to find suitable replacements in the hardware store if you cant source online. Look for stainless.

Soak the exhaust studs with a good penetrating oil beforehand.

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

Ok, just making sure there wasn't an easier way. I use acetone and atf mixed 50/50 on rusty bolts and have good results. I tried all the nuts in my nuts bin and nothing fit so I wasn't sure if it was a hard to find thread for the nut.

it's a fiddly job. Remove the upper silver bypass pipe and there should be 4 nuts between the rear manifold and the turbo bracket, once out and the manifold stud nuts removed you should be able to wiggle the rear manifold off and access the accordion piece you are trying to replace.

Good luck

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

Contact the MB classic center. They were recently able to easily get me a variety of IP seals.

You’re lucky your leak is so easily seen. I feel like every 602/603 engine I have (except my w140) has an underhood exhaust leak. Not good for health. Hard to find…

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)