320 CDi Cracking noise, is there a resolution?

[G-a-r-y]

I've been looking back at this old post (below) because I have this very problem. The main agent fitted a new injector which didn't fix the fault (I was told it would) After having the techs out from the workshop I was told, yes we have heard this noise before but up until nine months ago Mercedes said there was no fix. They are re-contacting technical for me.

Is ther a fix??

I'm looking for some advice regarding an unusual cracking noise from a new 320 CDi engine plus consumer rights...

I bought an new E320 CDi estate last September and noticed a peculiar knocking/tapping/crasking noise in November. The noise is apparent when then the engine's hot, windows are down and the car is cruising along at around 1000 RPM.

When I took the car back to the garage I bought it from they said they hadn't heard the noise before and would investigate. The car's been back 3 times now and after the last visit (car booked in for 3 days to take the manifolds off and "get to the bottom of it" ), the garage showed me a document from Mercedes which indicated that this is a known problem related to number 1 cylinder.

Under light engine load, with the windows down, between 1000RPM and 1500 RPM there's a cracking noise eminating from the first cylinder. There is currently no solution to the problem and it wasn't clear what caused to problem or whether a solution was being worked on.

I'm concerning about long term damage to the engine and the effect the noise could have on resale value.

Since then the garage have suggested I pursue this further with Mercedes and vica-versa. I'm getting nowhere...

I'm looking for advise on a number of issues please:
1. Has anybody else come across this problem?
2. Does anybody know what's causing it?
3. Is it likely to cause long term damage to the engine?

4. Who should I take the matter up with, the garage or Mercedes.

Any advise would be greatly appreciated

 

[Uncle Benz]

I cannot offer much advice, but I have heard the noise you are describing. I assume we are talking about the inline six rather than the new V6.

I had a customer turn up very concerned with the car he had just bought. If you held the car on the brake in drive, and apply about half throttle for a few seconds, you could produce the noise every time. (Don't do this too much. It is called a stall test and heats the transmission fluid up very quickly). He eventually received assurance from Mercedes that this is known; is a problem with the number one piston; is apparently due to a 'build up of manufacturing tolerances', and would cause no premature failure of the engine. How much of this is true, and how much made up on the spot I do not know, but a couple of years on the car is still going well, and the noise has not worsened.

 

[iamamanc]

Is this noise what I call nailing or pinking, it sounds like a ball bearing is bouncing around. If so, one of the causes is the injector popping a little bit later than it should or the pump delivering a little too late, some people say supermarket fuel can also be a cause - or the injector is knackered. If you touch the fuel pipe which goes to the injector you should be able to feel the pinging. You could loosen the nut on the delivery pipe/injector head and see if it stops, wrap a rag around it to stop diesel spraying your best shirt. If it stops swap the injector with say number 3 and see if the pinging goes there, then you know it's the injector.

Cheers
Adrian

 

[G-a-r-y]

Thanks to both posters (you know what your on about) I've had a smooth running test, which I thought could shut down individual injectors, it doesn't.
You can't loosen off the injector pipes, not on a common rail system (you will loose all pressure)
Thought about pulling the plug off (the injector) but they are wired in series.

I will persist where Mercedes have failed.
My first idea is to add a "wetting agent" to the cooling system, this is what race engines use, it takes heat away from castings and casings (that's what it says on the bottle)
I'll then try a fuel additive.

 

[Uncle Benz]

Just to add to what Gary has said, NEVER loosen the injector pipes on a common rail system with the engine running. This is potentially EXTREMELY DANGEROUS and PERSONAL INJURY is a very real prospect.

It is acceptable to loosen the pipes on an old fashioned diesel injection system when looking for faults, but be aware that the injection pressure can still be dangerous, even on these.

 

[iamamanc]

Sorry for my ignorance as far as newer models are concerned. I hope I didn't mislead anyone.

Cheers
Adrian

 

[OlafMaxwell]

I have had this noise since new, now have 123k, it has never caused a problem and have never got anywhere trying to investigate it. We used to get something similar on motorcycles years back, was attributed to timing chains and tensioners, occurs at same point in every crankshaft rotation but the 320cdi engine seems bulletproof. Probably best to leave alone.

 

[G-a-r-y]

Just had a call from my dealer, Mercedes is telling them to change injector No 1 or 2.
No 2 was replaced last week so that leaves No1.
I have agreed to pay for the injector and they have agreed to do the work for free.
Do you consider this to be a good result?

 

[Rory]

Just had a call from my dealer, Mercedes is telling them to change injector No 1 or 2.
No 2 was replaced last week so that leaves No1.
I have agreed to pay for the injector and they have agreed to do the work for free.
Do you consider this to be a good result?

The car's under a year old and they want you to *pay* for the injector?

 

[G-a-r-y]

The car's under a year old and they want you to *pay* for the injector?

Car is 2000.

 

[Rory]

Car is 2000.

Ah - sorry. I read your OP as one post. :Oops:

 

[BlackC55]

The noise you are talking about is normal and nothing to worry about. I have had the complaint before and contacted MB technical dept and described the noise to them and they said its a common noise and normal.

 

[G-a-r-y]

The noise you are talking about is normal and nothing to worry about. I have had the complaint before and contacted MB technical dept and described the noise to them and they said its a common noise and normal.

Everyone tells me this noise is normal, however not all 320CDi suffer, just the odd few.
Mine didn't have this noise at 78k miles (when I bought the car) but now at 80k miles I have the noise.
Mercedes know of this problem but until now had no resolution.
I'm having more injectors fitted today, on Mercedes technical dept instructions.

Just had a call from the dealer. they have fitted injectors to 1,2,3,4,6 but can't get No 5 clamp bolt out.
No 5 has the highest spill reading? if the bolt breaks I'll have to pay?

 

[hmang]

5 brand new injectors and one at 80k+ doesn't sound ideal for a smooth happy engine.

 

[G-a-r-y]

Update, the car is still with them, I haven't had a call today??

 

[G-a-r-y]

Update for future reference.
The garage have changed all six injectors, the noise remains. They have re-fitted my originals with new seals and modified clamps/bolts.
They are waiting for Mercedes technical to give them the go a head to fit/try a new ECU. On this car the software can't be updated.
The general opinion is that the noise is cause by a fuelling problem.

 

[EPS]

i have the same cracking noise as well on my 2006 e320 cdi. i only have 35,000 miles and its a very distinct and loud cracking noise that starts from a standstill all the way through the first few gears. once you get to about 3rd or 4th gear it goes away. and it repeats itself all over again once you start from the next stop light. it sounds like it has to be damaging to the engine whatever it is that is making this nasty noise. i don't want to accept it. i still have 6 months of factory warranty left and i will be in the dealership tomorrow to begin finding an aswer to the problem. have you guys had any luck resolving yours? please let me know.

 

[malcolm E53 AMG]

Hi EPS and welcome to the forum.

The OP was discussing the in-line 6 engine, your engine as far as I'm aware is the V6 a totally different engine. Yours does sounds like an injector problem but with six months warranty let the dealer fix it.

I havn't read any posts that relate to a similar problem so please let us know the outcome. Most of the posts relating to the V6 engine have been about CPS (Crank Position Sensor) problems and the seven speed gearbox which has a tendency to stick in 2/3 gear.

 

[EPS]

hi Malcolm, my 2006 e320 cdi is an inline 6, not the V6. my symptoms sound exactly the same as described in this entire thread. its an unusual cracking/sharp pinging sound that i can hear when accelerating under low load and between 1000-2000 rpm. when the car is cold(after just started) it will crack less, but when fully warmed up it will crack and tap the most. sounds like a guy named Andrew Toomey has found a possible solution. this is what he posted below. let me know what you think...

Mrc E320 CDi cracking noise FIXED!!!!! - Andrew Moorey (Tune-Up)
Finally after complaining directly to M-B in Milton Keynes and Stuttgart and being told that it was an operating characteristic of the engine and that no action was possible and that it was not detrimental to the reliability or performance I let the matter rest and largely ignored it until a chance meeting with Vaughan Smith of AP Diesels in Englefield Green near Egham, Surrey at the 'Mechanex' at Sandown Park last year. He claimed that he knew what the problem was which was faulty injectors. I took the car in (now with 47000) on the clock and he removed the injectors and tested the deliveries and leakback rates. Sure enough, 4 were within spec but two were not, one with excessive leakback the other with poor delivery. Two reconditioned injectors later and the noise is gone, performance smoother and crisper and economy seems to be improved. I shall be contacting M-B for their comments and to let them know how to cure any more E320CDI's there are out there with the same 'incurable' problem!
Andrew


-EPS

 

[EPS]

I don't know why i called his last name Toomey. Anyway, i am working on scheduling an appointment with the Mercedes dealer here in Daytona Beach, Florida(where i live) to have the engine and injectors looked at. i plan on printing this entire thread to give the mechanic some background info on the other people having the same problem as i am having. i really hope i can get the car fixed and resolve this cracking noise. its an awesome car and feels buttery smooth, just has that irritating cracking noise from the engine. everything else on the car is solid.