OM603 Knock *****PLEASE HELP!!*******
Hi all.
Im writing this on behalf of my father, who is in desperate need of some help.
He has a 93/94 300GD with a "clacking" knock on tick over, as the revs are increased to say 2000rpm + the knock is no longer, as the revs decrease the knock comes back.
He's spent a fortune with the process of elimination by trying to cure this problem, we've tried new hydraulic lifters, camshaft, timing chain, injectors have been tested, diesel pump has been tested/advanced/retarded, big/little ends replaced, piston rings replaced and valve guides have been replaced, yet the knock is still as plain as when we 1st started.
The knock seems to be more "feelable" through injector pipe number 2 and it seems quite clear that the knock is coming from the top of the engine, has anybody else has this problem, could you help with a cure?!
My dads determined to cure it if it breaks him, i just dont want it to break him, or his bank account!!!!!
Many thanks.
For all it is worth, and I am not saying this is it without hearing it, but my dad had a 124 300d, with the same engine, and that mad a clanking noise at idle speed, and disappearing with higher revs. His sounded a lot like loose old fashioned tappets. His injectors were also tested, with no problem, but the noise disappeared when he had the injectors replaced.
When the engine is idling, open each injector line slighly one at a time and see how the knock is affected. You should be able to identify which cylinder is causing the problem. The revs should drop when each one is opened
Put a rag around the injector so you don't get messy.
I had a knock on my 300gd and it was a injector, but I see you have checked them.
I too have been trying to get to the bottom of this on a friends 124 with 603 engine.
I have a hunch it is the hydraulic tappets. Is the sound worse on warm up?
I am going to try an oil flush to see if there is any crud that could reduce oil pressure to the tappets. It's far worse on no 2 cylinder. I know this is a problem on the 230 engine (M102) to the point where if there isn't enough back pressure from the oil filter then the tappets will knock and eventually fail. OEM filter is a must.
We've replaced hydraulic tappits and changed the oil over and over due to engine being stripped down and rebuilt nearly every week!! Honestly this engine has been to bits over and over again but still the same knock.
And yes, noise is worse on cold start. It really has become almost like bashing your head against a brick wall, but it must be something causing it, it just seems to be baffling everyone!
Hello spoton,
Would you please answer if the head has been lifted?
Cheers,
How do you mean lifted, sorry im just the messenger.
The head has been off a few times since we have been trying to solve this problem knock.
OK. have you tried listening for the noise lower down.Just wondering if it could be a bit of piston slap???
Forget what causes it, just stick a nice OM606 in there!
Yes we've checked the bottom end, the sump has been off, shells have been replaced etc....
Pistons have been out and rings replaced....
Sorry but I don't have any more suggestions.
Would you live with it yourself?
Sadly it must be aliens hiding somewhere:(
Hi
talk to Crewe Engines they rebuild these engines and should know all of the problems that can arise ..failing that the OM 603 engine is available from "Breakers" at prices from £ 350 ( taken from W124 saloon cars) ..anybody checked the metering on the fuel pump as too much fuel at one injector will cause a very loud knock
Maybe the vacuum pump? If it is you need to change it quick, they can destroy the engine if they fail.
Even though the injectors have been checked I would still give the proceedure that Roly suggested a go.
Russ
No, it's not the vacuum pump either!!
Its a tricky one this, we have already tried what all of you have suggested, thanks for your input tho.
There are a few forums dedicated to tuning mercedes diesels. A google search might turn them up.
Lots of info here
http://www.w124-zone.com/news.php
Good luck and if you find an answer let us know please.
Can't really suggest any better ideas about the knock. I have had problems with one injector for some while and despite it being serviced twice it would cause a misfire intermitently. Have fitted a replacement and no further trouble or noises. Certainly injector pump timing or metering can cause knocking or rattling at certain revs.
If all else fails I have a 300GD engine sitting in my shed looking for a new home!
Good luck.
Hello spoton,
I have not had any feed back from your farther since we last spoke to each other. I have tried calling him on the number he had given me, but the line is not operational any longer, in the past I had spoken to him twice before but the line is not functioning now, something doggy here.
Any way, I was reporting back to say my contact in Leeds has not responded to my PM to him and enquires made to an American specialist has clearly refused any help on the grounds there are a lots of callers, he suggests that I get the answer from his web-site forum; this, I have done and does not answer the question put to him. I have spent a lot of time on this and getting no where.
I have done all I can, and can only say, the fault does not sound as though it will cause more damage, he could learn to live with it, turn up the music OR, record the sound and post it on utube to see if any one replys back.
Good Luck,
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Yes, have tried loosening injectors, still hasnt given us any more clues.
Injectors have been tested and are perfect it would seem silly to replace all 6 after what has already been spent, i believe there around £90 each.
Any other ideas??
Thanks