M117 Exhaust manifold leaks ~ Gasket Change?

[JeffreyNMemphis]

Hello Peaches,

I hear the sound of exhaust leaking from the manifold on my 1973 280SEL 4.5 liter. Does anyone have experience repairing this? Is it a giant PIA to change the exhaust manifold gaskets?

[bwostosh]

Question, Drivers or passenger side?

I had the same problem except there was a crack in the drivers side exhaust manifold.

You may not like this answer...........

I took the fenders off. yes really.

Seems like the only other way was to pull the head. Pain.
The manifold nuts were accessible. don't break a stud off.

and cleaned, replaced, those inboard front end parts, motor mounts, and everything else accessible, like valve adjustment spark plugs, etc.

[JeffreyNMemphis]

Driver's side...

[bwostosh]

First thing is to tighten the bolts and nuts attaching the head pipe to the exhaust manifold. They can loosen with many heat/cool cycles.

[TnBob]

If you do pull it, replace the nuts with brass ones.

[Graham]

Originally Posted by JeffreyNMemphis

Hello Peaches,

I hear the sound of exhaust leaking from the manifold on my 1973 280SEL 4.5 liter. Does anyone have experience repairing this? Is it a giant PIA to change the exhaust manifold gaskets?

I had a muffler shop replace mine. They didn't charge much. the gaskets are cheap and available from any MB dealer. They look like large O-rings when new. they are made from aluminum and flatten out in time.

I am assuming your '73 280SEL 4.5 has similar pipes to my '72 SL. There were some changes in the pipe-manifold connection, so later cars may be different. the shop manual has a survey of the many variations in manifold and joint design.

Do check for cracks - the most likely place is on passenger side between the #3 and #4 exhaust ports. Usually on top so you should see these looking straight down, just in front of where pipe turns downwards. If you have cracks, manifolds can be removed on the SL, so probably also on your car. But studs are spindly and breakage is possible. Don't ask me how I know! Had to remove head to get broken piece out!

[JeffreyNMemphis]

I soaked the nuts and bolts in WD40, in anticipation of attempting to tighten them.

[Tomguy]

I didn't need to take the fenders off & I dont see how it'd help get clearance?

The driver's side is a 1 piece & yes, it's a PITA. Studs breaking is usually the cause. The 1 piece manifold can also warp & crack, too. The RIGHT way to do it would be to remove the head, but I've done it without removing the head...

My trick: Gently jack up the engine using a 2x4 under the oil pan sideways so it doesn't crush the oil pan. It should then allow you JUST ENOUGH clearance to get past the studs & pull it out to replace the 4 gaskets.

[PanzerSD]

What?? I've had my exhaust manifolds off three times in the last month, and I didn't find it to be hard at all..I'd say just as easy as removing the manifolds from a 617..but that could be me..

[Tomguy]

There's more room in a 116 than in a 108. about 1" more on either side. Makes a big difference Plus the engine is a little higher than the frame rails when compared to a 108.