M120 reliability

[buccal]

Always fancied taking the ultimate plunge on a V12 but never came close to having enough guts to pull the trigger.

I've read the various threads on the forum but still can't get a real grasp on how ruinous they could be to run.

On the one hand I've done the Harry Metcalf video to death in which he reckons its extremely reliable. On the other I don't want it to leave me destitute.

Car would be for high days and holidays only so petrol isn't an issue.

Anyone able to give me some context?

 

[SL300-24]

I had a V12 W140 which my mate now owns. I had it 2 years and he has had it 6 years. All it needed in that time was 2 coil packs about 50 quid each and normal servicing. They are a superb engine and it did 24 mpg on a run.

 

[ivan1983]

I have researched this quite a bit and nearly bought one, on the whole I would say that these are reliable engines. From what I understand they are loosely based around outting together 2x M104 engines.

However if things go wrong it can get expensive, as generally it seems to have 2 of everything and there is very little space to work in the engine bay.
If you can go for a later model with the distributor-less ignition that should reduce complexity a bit and you might also get the 5 speed box.

Its also much less costly to maintain than the V12 that followed it!

 

[millo777]

As others have said, the main issue is lack of space in the engine bay so jobs that are normally an easy diy end up needing a lift for access.

Even changing the spark plug on cylinder 12 is a pita

Like the m104, the timing covers can leak oil onto the alternator which washes all the grease out of the bearing.

In 7 odd years mine has only needed a water pump, and alternator and 1 coil pack over the normal servicing.

On the whole it's been a very reliable engine, and the driving experience is awesome.

There's just something special about a v12 imho.

 

[millo777]

It also seemed mildly comical to me when one of the coil packs died, telling my indie "I think it's only running on 11"

 

[buccal]

As others have said, the main issue is lack of space in the engine bay so jobs that are normally an easy diy end up needing a lift for access.

Even changing the spark plug on cylinder 12 is a pita

Like the m104, the timing covers can leak oil onto the alternator which washes all the grease out of the bearing.

In 7 odd years mine has only needed a water pump, and alternator and 1 coil pack over the normal servicing.

On the whole it's been a very reliable engine, and the driving experience is awesome.

There's just something special about a v12 imho.

Thanks for the replies everyone.

Millo, that sounds very reassuring.

In 7 years in my 55 I've only needed an alternator and an aircon condenser.