Noises from Engine

Pistonbroke

New member
2002 311 CDi diesel sprinter chassis cab with box body and 31k miles from new - lives in UK

Hi, Just completed a 250 mile motorway run last night, when I got to my destination, I noticed that the engine seemed to be knocking loudly when blipping slightly above tick over, but disappeared when revs raise above around 2000 rpm, the noise was very noticeable and my first thought was camshaft or small end, but when restarted later today despite running the engine for 20 mins to warm up I was unable to replicate the fault. Any advise what this can be.

Also, the engine seems to produce a noise which sounds like pre ignition on a petrol engine at 2200 but disappears when revs rise, anyone else experience this or is it a regular characteristic

And finally when the engine is on tick over, after about 40 seconds it runs lumpy, as though one injector is intermittent on tick over, anyone with ideas on this also?


Thanks in advance

Jon
 

andysprinter

New member
Sounds pretty much like one of the injectors is the problem.

I have also had the hydraulic tappets make intermittent "tapping" noises which can be there 1 day and gone the next.

31000 miles from new? that's rare.

How long has the oil been in the engine? Bad oil can cause hydraulic tappets to stick....

Sprinters can also change "tone" on tick over, it's quite normal.
 

mean_in_green

>2,000,000m in MB vans
Almost certainly an injector - a leak off test and a short test with a laptop will provide more of an insight.

Can sound horrendous, and a much worse problem than it really is.
 
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Pistonbroke

New member
Sounds pretty much like one of the injectors is the problem.

I have also had the hydraulic tappets make intermittent "tapping" noises which can be there 1 day and gone the next.

31000 miles from new? that's rare.

How long has the oil been in the engine? Bad oil can cause hydraulic tappets to stick....

Sprinters can also change "tone" on tick over, it's quite normal.
Thanks for the prompt reply: I dont think its a tappet, I am suspecting a bad injector so have put some injector cleaner in as a first attempt fix, as I have a run round the M25 on Tuesday and dont want to strip it prior.

The oild is only about 4k old, 3 months

The Van came from a large UK lease company last year, and had only 10k miles as been used as a site vehicle by the maintainance department of the company I leased it to, in fact they had two and I brought them both and sold one, which reduced the cost of the one I kept.

Its got a Luton body so Its difficult to get into my workshop!

Thanks again
 

mean_in_green

>2,000,000m in MB vans
Be cautious about using injector cleaner. MB issued a service bulletin warning about it: most have a high petrol content, which eats diesel engined fuel circuit seals for breakfast.

Peversely the petrol engined Sprinters have seals of a different composition which are quite happy with the stuff...
 
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Pistonbroke

New member
Almost certainly an injector - a leak off test and a short test with a laptop will provide more of an insight.
Thanks for your answer, but what exactly is a leak off test? and if the problem is an injector how does a laptop show it, does the firing signal show as faulty.

also does a new injector need to be calibrated or is it just plug and play?

thanks in advance
 

Pistonbroke

New member
Be cautious about using injector cleaner. MB issued a service bulletin warning about it: most have a high petrol content, which eats diesel engined fuel circuit seals for breakfast.

Peversely the petrol engined Sprinters have seals of a different composition which are quite happy with the stuff...
I will bear that in mind, 6 months earlier I stupidly refueled my CLK 270 Diesel with petrol, drove it two miles before I realised, had it drained down and lucliky seemed to have got away with it.
But I wont put anymore injector cleaner in now my sprinter. Do MB supply their own?
thanks in advance
 

mean_in_green

>2,000,000m in MB vans
MB were using a particular brand, but stopped following the previously described issue. No equivalent product is currently endorsed in the UK as far as I'm aware.

A leak off test is just a way off observing how much fuel an injector is passing. It's a pretty low tech method involving some clear tubing and an extended idling period in the workshop and comparing the throughput, but it is a good indicator of a fuel delivery problem. Other tests can be done with a laptop.

It's not a difficult problem to diagnose or fix: typically it's a singular injector, but the job does have potential to get spendy if two, three, four or more are worn out. Sometimes a new one can upset the other older ones too.
 

Pistonbroke

New member
Finally had the Van fixed today, all the noises were due to one faulty injector. I noticed with the faulty injector the the enconomy went up by 20%, or was that me just nursing it along.
sorted now, runs like a dream

I used a mobile Mechanic who was Ex Maindealer and had his own star diagnostic unit, also we went through the recoreded faults and I previously mentioned that I had changed the fuel filter and ever since had intermittant managemet light come on, seems was due to the fact I never put grease round the o rings on the fittings on the top of fuel filter.
Not a lot he doesnot know about MB's

He is Based in Bromley, Kent UK. called Tom and email is mercman68@yahoo.co.uk
 

hkpierce

'02 140 Hi BlueBlk Pass
I used a mobile Mechanic who was Ex Maindealer and had his own star diagnostic unit, also we went through the recoreded faults and I previously mentioned that I had changed the fuel filter and ever since had intermittant managemet light come on, seems was due to the fact I never put grease round the o rings on the fittings on the top of fuel filter.

I never heard of this. Someone care to elaborate and, if true, what type of grease?
 

mean_in_green

>2,000,000m in MB vans
I usually just smear with oil, grease seems to thick for the suggested purpose. Just helps the seal to seat properly.
 

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