C240T Manifold Crack

[seymansey]

Hi Guys,

The manifold on on my C240T has appeared to have cracked, specifically the driver side, on the cylinder furthest back. Seeing as the car hasn't really gone much over 100k i'm suprised this has happend really.

ANy anyone changed the manifold themselves before? Looks pretty tight down there - is it something that can be done DIY with a ramp maybe?

 

[television]

As you have inlet and outlet, which one has split

 

[Will]

I'm sure it must be the exhaust manifold as it's the driver's side, the inlet manifold is one piece IIRC.

Not done a manifold on that engine before but they can be tricky when access is tight - good luck

Will

 

[seymansey]

Silly me, it's the outlet

I've patched the problem for now with exhaust paste, as I don't fancy driving round with a machine gun noise but i'll have to get it resolved at some point.

 

[television]

As will access is tight, the hardest one to get to is the rear most nut, and I know when doing a head gasket its almost easier to take it off with the head.

I will see If I have some instructions

 

[grober]

You might be able to repair it by welding but since the bulk of the work will involve its removal and replacement I would get a new one. There seem to be 2 types ??http://www.detali.ru/cat/oem_mb2.as...GM=716.626&CT=M&cat=19X&SID=14&SGR=060&SGN=02
Personally its a job I would entrust to a good specialist with access to lots of specialist sockets/ spanners car lift etc. Exhaust bolts and manifold studs can be tricky to remove. If you are an experienced DIY man OK but otherwise be warned.

edit I am assuming its a v6 petrol??

 

[Will]

As will access is tight, the hardest one to get to is the rear most nut, and I know when doing a head gasket its almost easier to take it off with the head.

I will see If I have some instructions

Yep, the manifold on my 2.5-16 was so tight (it's like a bunch on bannanas), that removal in situ is very fiddly/time consuming, so I took it off with the head instead.

Even on a bench it was quite fiddly, 1/4 drive sockets with lots of extensions/joints etc, and some delicate spanners with flexible heads.

As Grober has said, you wouldn't want to be doing this job more than once really, so it might be worth buying a new one for peace of mind

Are the engine/exhaust mounts etc all sound? Might be another reason why it's cracked.

Will

 

[seymansey]

You might be able to repair it by welding but since the bulk of the work will involve its removal and replacement I would get a new one. There seem to be 2 types ??http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=202088&M=112%2E915&GA=722%2E696&GM=716%2E626&CT=M&cat=19X&SID=14&SGR=060&SGN=02
Personally its a job I would entrust to a good specialist with access to lots of specialist sockets/ spanners car lift etc. Exhaust bolts and manifold studs can be tricky to remove. If you are an experienced DIY man OK but otherwise be warned.

edit I am assuming its a v6 petrol??

Yup, it's a V6 petrol. The manifold is item 5 in the link.

From what has been suggested and for my own sanity, taking the head off might be the way to go. I'd have thought from a MB Workshop POV i guess the 'correct' method would be to remove the engine, though would seem a little extreme.

Are the engine/exhaust mounts etc all sound? Might be another reason why it's cracked.

Will

As fas as i can tell they seem OK, although this was the first thing that popped into my head, because the manifolds themselves look very clean and rust free indeed. I might have to have a check of the shock absorber on the bottom of the engine to check for excess play.

 

[television]

If you do decide to go ahead and remove it, it is said that the freezers now sold as as good as using heat, after all it is the shock that releases the offending nuts.
A couple of new good make sockets would do no harm to start off with.

I asked a question some time back, what are best hex or splined sockets

 

[sweeper]

If you do decide to go ahead and remove it, it is said that the freezers now sold as as good as using heat, after all it is the shock that releases the offending nuts.
A couple of new good make sockets would do no harm to start off with.

I asked a question some time back, what are best hex or splined sockets

Hex are best in my opinion, especially where the nuts are slightly corroded or rounded.

 

[grober]

If you can get it off without removing the head that's the way to go. Removing the head means disturbing the valve timing chain, front crankcase seals draining the fluids new head gasket, removing the inlet manifold much of the injection system. the list and cost goes on a long long way. The more you disconnect the more there is to go wrong on re-assembly. I always think its not a good idea to break all the factory engine assembly seals unless absolutely necessary. If its absolutely necessary a "partial" removal of the engine+gearbox i.e. to lift it up/forward slightly to access the manifold would be preferable IMHO

 

[Will]

Hex are best in my opinion, especially where the nuts are slightly corroded or rounded.

Ditto

Will

 

[Will]

If you can get it off without removing the head that's the way to go. Removing the head means disturbing the valve timing chain, front crankcase seals draining the fluids new head gasket, removing the inlet manifold much of the injection system. the list and cost goes on a long long way. The more you disconnect the more there is to go wrong on re-assembly. I always think its not a good idea to break all the factory engine assembly seals unless absolutely necessary. If its absolutely necessary a "partial" removal of the engine+gearbox i.e. to lift it up/forward slightly to access the manifold would be preferable IMHO

Agree 100%, I didn't remove the head to get at the manifold, I needed to remove the head for a totally unrelated reason (de-coke and overhaul).

It was just easier to remove the head with the manifold attached, as opposed to removing the manifold in situ

Sorry if there was any confusion,

Will

 

[Will]

I'd also apply a penetrating solution to the nuts/studs and let it soak for a while. Consider replacing the nuts if they're in less than perfect condition

Will

 

[mikevernon]

Seymansey, I don't envy you. If the exhaust manifolds are as inaccessible as they are on my V6 SLK, it looks like a horrible job. But don't even think about taking the head off to do it.

Many years ago I borrowed a friend's Golf GTi on Christmas Eve. I drove into a car park and caught the sump on one of those fold-down barrier post things. Not only did it hole the sump causing instant loss of its liquid contents, but the slight movement of the engine snapped all four primaries of the cast iron manifold. Being Christmas I couldn't get hold of any new parts quickly so I stripped it and had the sump brazed and the manifold bronze welded. I spent the rest of Christmas Eve, Christmas Day and half of Boxing Day underneath that car, so I wasn't the most popular member of the family that Christmas.

The repaired sump and manifold were still working perfectly when my friend sold the car 3 years later.

 

[television]

Cast Iron can only be welded when it is 400c or more, and the cooling down from this is critical, and must be as slow as possible

 

[mikevernon]

Bronze welding is generally accepted as the easiest and most practical repair method for cast iron exhaust manifolds. The name is misleading because it does not involve fusion welding of the parent metal (iron) but instead uses a bronze alloy filler rod in a process more like brazing. There is far less risk of distortion than when using a fusion welding process, and in fact is quite easy. I've used it successfully three times on cast manifolds.

 

[c240yaz]

Welding cast iron is never a guaranteed fix. From my experience, it never works, unless in laboratory controlled conditions.

 

[television]

Welding cast iron is never a guaranteed fix. From my experience, it never works, unless in laboratory controlled conditions.

One thing that does work is metal stiching, and is perfect for cast iron

 

[c240yaz]

One thing that does work is metal stiching, and is perfect for cast iron

TV, That's a new one on me, please explain.