I have had my 240 since November 06, and the whole time it has had a small exhaust leak. I never went looking for it with the idea to fix it, I felt it was coming from where the pipe turns under the car. And I planned on replacing the whole system "soon", so I let it go. Today I learned otherwise, it's coming from the manifold at the head!

I have nearly 30k miles on this car with this leak, and i don't have any idea how long the PO let it slide. But now I'm getting concerned about possible engine damage. The odometer is at about 290k, as it works when it wants to. (I know, it's the dash knobbie, researched that already ) So is this repair better suited for a shop? Will the manifold need to be machined? Is my motor dying a quicker death?

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1981 MB 240D - 280K miles (My Iraqi LAPC )



My stable also includes:
2003 Honda Odyssey - Wife's van
1976 IH Scout 2 - SUV recovery vehicle
1967 Dodge W200 - The big block hauler (440/4sp.)
1966 Dodge D100 - The Redneck Racecar (440/727)
1925 Dodge Roadster - My electric car canidate

True health starts here

I've heard that running a gas engine with no manifolds or with a bad manifold leak can cause a burned exhaust valve due to fresh air being sucked in through the exhaust when the throttle is suddenly closed. I've never actually seen a case of this happening.

On a diesel engine, since there is no throttle, the gas flow stays in the same direction, and the engine just pumps fresh air through the cylinders when decellerating with no accelerator input anyway, so I would say the chance of engine damage is nil.

However, in the interest of not breathing a bunch of diesel exhaust every time you drive, you probably do want to fix that. The basic task is theoretically easy, but rust on the fasteners can make it a PITA. I would get a new gasket and slap it on myself, but I wouldn't start taking the fasteners off until after repeated soakings with PB Blaster, WD 40 or another such product. I've heard of machining a manifold true, but this is very rarely needed.

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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.

Its not a hard job, just a bunch of 17mm nuts to undo. The manifolds can be kind of ornery to get off sometimes, a rubber mallet helps. I've noticed usually the first thing too go in the exhaust system is the "header" pipe (the piece bolted to the manifold) so be sure to check that for holes.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Hi:

I replaced the cracked exhaust manifold on my 240d in ~2 hours using a "previously loved" manifold purchased from another forum member.

Before starting the job, have the new gasket in hand as well as a new set of hardware for the exhaust pipe and new lock washers for the lock-down nuts on the head. Before I took them off, I pre-soaked the nuts on the head with penetrating oil, and I ended up using the Dremel on the exhaust pipe hardware as it was encrusted with rust.

Good luck!

IF you had warped a valve from cold air hitting it, you'd know it immediately, if it still runs fine, the valve is fine. It has now been run long enough wit hthe leak however, that erosion of the gasket sealing facing on the head and manifold could be a concern, and possibly manifold warpage as well, clean and check the facings carefully when you pull it apart, and have the manifold checked with a good machinist's straightedge, it may have to be milled flat if it is warped.

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Chris
64 190D R.I.P.
80 240D W/617 engine -for sale
82 240D -for sale