I've got a 2004 ML350 with 47k on the clock. It was throwing codes (O2 sensor and a right fuel bank problem, depending upon where you go to find code meanings online), so I brought it in. Mechanic calls me and sez its a cracked intake manifold. Used replacement will cost me about 1100 total, which seems reasonable if it needs to be done.

I didn't look at it but while driving I never noticed any hissing, rough idle or other problems. Thinking of going back down to have a look and maybe just JB weld it if the crack is small enough. I know there is a risk the JB weld could get into the intake system, though.

This intake is not made of plastic like some others, but aluminum. How likely is it that it cracked after so few miles (or at all, really)?

Thoughts?

__________________
Gil

2004 ML350
1984 300CD; Ivory (sold)

I am sure it happens. If JB weld it used on the outside, I doubt it would get sucked in after being set. The other option may be to have it welded by someone with the skill to weld aluminum. Not sure if brazing would work also. Welding could cause warpage though and you still have to deal with removal and reinstall.

__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

That's what I was thinking - a proper weld would be difficult and no cheaper than swapping it for a used manifold. Really tempted to just go with the damn JB weld since as long as it holds no performance difference should arise.

__________________
Gil

2004 ML350
1984 300CD; Ivory (sold)

According to the mechanic, he used smoke and diagnostic codes to find the crack. I had to ask about JB as a cheap alternative, but he said JB won't last there, since the problem is from the crappy aluminum used in the intake (sez he's seen a few of them crack). Anyway, JB weld would take care of the initial crack but would do nothing to prevent the metal from cracking further or deteriorating. Sound about right?

It's not an unreasonable price for the job so I'm probably just going to go with it.

__________________
Gil

2004 ML350
1984 300CD; Ivory (sold)

Well its your money. I would ask for the old intake. Call me paranoid, but put a dot of paint on it somewhere so you KNOW its yours. Then when you have it take some pics for the forum. Would be interesting to see.

You may also want to call MB directly on this. They *may* have a silent recall. Or at the least, they may cover parts cost. I only suggest because its an odd flaw. All you will spend is some time and a phone call and it may be well worth it.

__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

Take it to another mechanic if you are concerned about someones honesty.

__________________
68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

Manifolds on these engines are magnesium and include solenoids, etc., to vary intake tract length.

http://en.wikipedia.org/wiki/Mercedes-Benz_M112_engine

I'd want my mechanic to have factory training on this engine.

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Swapping an intake manifold on an M112 is simple. Any decent mechanic should be able to do it without any fuss. FWIW, cracking is rare, but it does happen. I've seen a handful over the years, and the smoke machine is definitely the way to diagnose the problem. Also, there is no "silent recall" that I'm aware of, but given the age and mileage of the vehicle it's definitely worth making a phone call to MBUSA to see if they'll help out.

Well, if I could find the crack I sure would JB Weld it in a hurry. Get another crack, do the same thing. For a dollar or less and in 10 minutes it is fixed. When it is good and hard, in about a day, paint it silver. But you have to be able to see it and be able to get to it.

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

I would have the crack tig welded. I've had that done to both of my Cats on 1999 ML 320. One cat was done about 5 years ago and the other was done last week.