V6 320 cdi - How ruinous?
Discussion
Hi hope some owners on here can help. OM642... Yes or no? Thinking of an S204 pre f/l car, to date have mainly been focusing on an early pre BE 220 cdi as they seem pretty bullet proof, but really like the idea of the extra grunt and refinement that comes with the 320cdi. But... Heard all sorts of horror stories about the 3.0 v6 dervs / OM642, how much of it is valid and how much has it been unfairly maligned by just a few high profile failures?
Specifically referring to inlet port shut off valve and (even more so) the front crankshaft bearing.
So... OM642 owners past and present, how many headaches have you actually had?
Specifically referring to inlet port shut off valve and (even more so) the front crankshaft bearing.
So... OM642 owners past and present, how many headaches have you actually had?
We have 2 - a CLS from new now on 122k miles and an E class from 43k to 112k. Both are early cars (06 and 09) so first generation OM642s. Both cars needed an inlet port shut down motor at around 80k. The CLS had a new turbo and precautionary change of inlet motor ("while we're here") at 118k miles. The E, my wife's car, sometimes hiccups and limps, but that's because she never gets anywhere near full throttle so the turbo soots up, but a good bit of exercise with the right foot clears that.
The turbo etc. was fitted by an indy (£1,300 inc 2 glow plugs) but both cars still have full MB service history. They use hardly any oil (probably 3 litres across both cars' life so far).
Considering the relative sophistication of both engines, I don't feel the history is too bad, and the low down torque of the engine is something I really appreciate.
The turbo etc. was fitted by an indy (£1,300 inc 2 glow plugs) but both cars still have full MB service history. They use hardly any oil (probably 3 litres across both cars' life so far).
Considering the relative sophistication of both engines, I don't feel the history is too bad, and the low down torque of the engine is something I really appreciate.
Thanks for that insight, very interesting. So the inlet port shut off motor sounds like a given, at a certain mileage. What is the approx cost at an indie for this job alone? No crankshaft bearing issues then, that's encouraging.
There is an S211 320 cdi AG at the place where I'm due to view an S204. It's a late car, 2009, with almost 100k on clock but with full MBSH, and nice condition. May well take a closer look at that too while I'm there.
Have you had any issues with the 7G box in either car?
There is an S211 320 cdi AG at the place where I'm due to view an S204. It's a late car, 2009, with almost 100k on clock but with full MBSH, and nice condition. May well take a closer look at that too while I'm there.
Have you had any issues with the 7G box in either car?
I have this engine in my CLK & can't fault it but mine is at low miles so I haven't had any issues the 7g box is very robust but you need to make sure the fluid & filter have been changed if not (or just for peace of mind) an indy will do it for £150 ish drivetrain wise you shouldn't have any big issues.
Regarding the inlet shutoff motor, this used to be a very common and expensive problem, however there is a proven fix of fitting a 4.7k resistor across the disconnected motor plug, which then acts as an emulator, preventing a fault code and more importantly holding the inlet flaps in the open position. This has no detrimental effect on emissions or performance.
Have run a CLS now up to 85k from 40k.
Had full Merc history and serviced every year since new. Only thing that has broken was a boost pressure sensor in the exhaust.
I'd advocate changing the turbo inlet seals each service to prevent them dripping onto the inlet motor below for the sake of a tenner.
Had full Merc history and serviced every year since new. Only thing that has broken was a boost pressure sensor in the exhaust.
I'd advocate changing the turbo inlet seals each service to prevent them dripping onto the inlet motor below for the sake of a tenner.
That's exactly it, the the crankcase breather dumps into the turbo inlet, where the oil residue then leaks past the seal and drips into the motor which is directly below in the V. As a belt and braces measure, I have modified the inlet pipe with a silicone tee section and clamps, fitted an emulator resistor and finally an inline catch can between the engine and inlet.Total cost of about 150 quid for piece of mind.
Between my wife, brother and I, we've had five cars with this engine. The oldest was my MY08 ML320 which is the only one we've had any issues with at all.
There have been three E350s between my wife and brother, and I now have a GL350. These four have all been perfect but none of them are above 60K miles yet.
The ML320 had some stuttering issues when I transitioned from low load running to high load running (basically, after sitting behind someone at low speed on Welsh roads, and then finding somewhere to overtake). It felt more likely that the waste gate was playing up however before I could look into that, I noticed that the turbo had started to whine quite audibly. I faffed around deciding what to do with this for over 12 months. Merc wanted over £3K to fit a new turbo, and Halfords £1200 to fit a recon (I'd have been happy with this) before finding a GL of the right spec, so I traded the car in.
That same ML had received three separate starting plugs and a new plugs management box in it's life. But truth is, it usually ran beautifully - and I ran it hard. I traded it as it approached 20K miles and got only £7K for it. Despite the small issues with the turbo, I would have had no conscience recommending it to my family or friends.
There have been three E350s between my wife and brother, and I now have a GL350. These four have all been perfect but none of them are above 60K miles yet.
The ML320 had some stuttering issues when I transitioned from low load running to high load running (basically, after sitting behind someone at low speed on Welsh roads, and then finding somewhere to overtake). It felt more likely that the waste gate was playing up however before I could look into that, I noticed that the turbo had started to whine quite audibly. I faffed around deciding what to do with this for over 12 months. Merc wanted over £3K to fit a new turbo, and Halfords £1200 to fit a recon (I'd have been happy with this) before finding a GL of the right spec, so I traded the car in.
That same ML had received three separate starting plugs and a new plugs management box in it's life. But truth is, it usually ran beautifully - and I ran it hard. I traded it as it approached 20K miles and got only £7K for it. Despite the small issues with the turbo, I would have had no conscience recommending it to my family or friends.
The stuttering issue is indeed usually the variable vanes on the turbo, however it is not the turbo itself but the actuator, which can suffer from poor electrical connection onto the printed circuit board, this may be fixed by anyone who is competent with a soldering iron in half an hour.
ZX10R NIN said:
I have this engine in my CLK & can't fault it but mine is at low miles so I haven't had any issues the 7g box is very robust but you need to make sure the fluid & filter have been changed if not (or just for peace of mind) an indy will do it for £150 ish drivetrain wise you shouldn't have any big issues.
Mine went through a phase of sticking in second, and refusing to change up or down. Turns out there was a sensor thing about the size of a sugar cube on the side of the gearbox. Cost me £1,400.I had a Brabus upgrade on mine, and I thought it was a great engine.
I ran a 2007 E320cdi Estate for 6 years, lovely car. 7G auto stopped shifting after 3 years and needed new valve body thing (Merc fixed under warranty, but don't think they are cheap), Turbo inlet seal leaked at year 4 sticking the inlet flaps - £2200 to fix but again Merc picked up the tab. Year 6 Turbo seal leaking again, Merc replaced seal as last one was within 3 year warranty period. Year 7 gearbox started displaying signs of fragility again (harsh shifts) ----- at that stage I baled out!
Lovely car though, and couldn't fault Merc on their approach (mobilio life breakdown service really is very good!).
Jim
Lovely car though, and couldn't fault Merc on their approach (mobilio life breakdown service really is very good!).
Jim
That's a little worrying, though I guess the chances of getting all that grief in one car is minimal, though of course possible.
Moral I suppose is try to get one with MB warranty, or young enough to have one put on, for that extra piece of mind.
Thanks everybody for sharing your experiences, all valuable stuff.
Moral I suppose is try to get one with MB warranty, or young enough to have one put on, for that extra piece of mind.
Thanks everybody for sharing your experiences, all valuable stuff.
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