timing chain tensioner

[runningman]

1998, 300 td, 606 engine.

does the timing chain tensioner adjust automatically as the chain wears? or does it need adjusting manually?
If adjusted manually, how is it done? do you run engine and adjust it whilst listening to it?

 

[martyz]

It's self tensions (hydraulic),being pre primed with engine oil before fitting.

 

[martyz]

and here it is;


View attachment 42909

 

[runningman]

thanks for that. if I want to check it for wear what do I look for? and is it just a case of unscrewing it, taking it out then putting it back without the need of special tools.

 

[martyz]

Yes it will unscrew,probably best to replace as its non adjustable,most importantly make sure it's primed(loaded with oil) otherwise it will fail to work.Fill a container with oil and submerge the plunger and press down to draw oil in,do it a few times until you are happy it's loaded.
I would set the engine to tdc on it's timing marks on the crank pulley and it might be a good idea to remove the rocker cover and wire the chain to the camshaft socket as a precaution.I don't think it would slip though.

 

[johnsco]

If you are going to remove the timing chain tensioner, invest in a new sealing washer first.
These seals often leak even if they have not been disturbed.

Is there any evidence that the tensioner is not working ?
I've done 150000 miles in a couple of these cars and it has never been an issue ... Other than a leaking seal washer on one of them.
I cured that by simply tightening the tensioner a touch against the washer.

 

[runningman]

thanks for all the info.
I don't know if you all have read my previous related posts titled 'engine knocks at 1250 rpm'. For the full story you may have to research back over the past 10 days.
This is still an on going saga, cut a long story short.
engine suffered bad starting one morning so I re[placed all glow plugs and all was well. then I noticed a knocking at idle and up to 1250 rpm, rev the engine higher and knocking disappears, let the revs fall and knocking returns at 1250rpm and back at idle.
Replaced all fuel lines, filters and had injectors refurbished TWICE (same specialist, im still convince that the injectors are faulty), checked all dampers, aux tensioner, new engine oil with hyd valve treatment.
Engine still knocks within that particular rev range (idle and 1250 rpm) otherwise it runs smooth as silk.
This knock suddenly developed. my dad thinks it coincided with the replacement of the glow plugs. glow plugs were the correct one for the engine same part number.

Car has done 47000 genuine miles with FMBSH.

The car is going into mercedes on Tuesday for a diagnostic and hopefully they will pin point the problem.

like I said please read back old posts for full story as its a bit long winded to explain it again.

 

[runningman]

when i changed the oil and filter i used a non-original filter. Now, ive read on other forums that non-original filters can effect back pressure. Which in turn causes the hydraulic lifters to knock and eventually fail, is this possible?

i changed the oil and filter back in January using 5w 30, the car had covered 2000 miles before the knocking started. last week i changed ONLY the oil for 10w 40, hoping that the thicker oil would cure the knock, but no.

 

[johnsco]

In the past 7 years I have changed the oil and filter on our E300TDs around 15 times.
I have used filters:
MB A602 180 0009
ECP 501 222 0158 (Crosland L0053DE)
ECP 501 220 150
Mann HU718/5x
Mann HU951x
Hengst E172H D35
FRAM CH8871ECO
Trucktec 02.18.033
Knecht / Mahle Lx927

All have done what it said on the tin with no issues.

Do not be too-precious about your oil filter.
I don't agree with the comments on the other Forum about back-pressure.
These are well-designed, robust and VERY-FORGIVING engines.
They are not going to complain about "fly-****" issues.
They want their regular oil and filter changes using an oil to the MB spec.
Do that regularly and they will look after you.

The only regular pain-in-the-A issues that are regularly-reported here are:
Glow-plugs
Leaks from the seals on all those silly little plastic pipes and joints (not MB's best idea)

Longer-term you have issues like inlet-valve recession, diesel-delivery-valve seals.

You get the odd vac-pipe failure ... I had one last Autumn

I find it hard to believe that your noise is not a fueling issue of some sort.
Hope you find it soon.

Yours is a low-mileage car.
Problems with hydraulic lifters may have arisen if:
- If it's been run for any length of time with a completely-unsuitable grade of engine oil
- If it's not had its oil changes
- If it's been used a lot for short journeys, which has filled your oil with moisture, and then the car's been left unused for a long time
- If the car's been stored and not used for some time (with mucky oil in it)
- Any combination of the above

My money says that a hydraulic lifter problem is unlikely .... But I don't know the previous history of the car and its maintenance.

 

[Dieselman]

These cars use pleated paper filters, not canister ones, so there is no anti-drain back valve built in to the filter, hence no drain back issue.

The knock won't be the timing chain tension, possibly the timing gear has stuck, try an engine flush.

You check the chain wear by turning the cam to TDC then checking how far advanced the crank it. 6 deg is the limit.

 

[runningman]

Cheers to everyone for your help its greatly appreciated. Car is going into Mercedes on Tuesday and fingers crossed they find what is causing the knock.

Regards

 

[runningman]

Took car to Mercedes this morning and they diagnosed 3 faulty injectors and also gave me a written report and costs. So back I went (for a third time) to the injection specialist that refurbished them. He listened to the engine and didn't bother arguing as he new the injectors were not right. He offered to check injectors again and if they failed he would replace all 6 with brand new ones.
Im guessing he will just scrap them and supply new ones and maybe give his mechanic a bollicking.

 

[johnsco]

I'm pleased to hear that you have an answer to the questions.
Hope this sorts it.
I'm a bit surprised to learn that you have two faulty injectors on a low-mileage car.
One in six ....... Well ........ OK
Two ....... !! ??


My first car got wrecked at 150,000 miles.
Present one has 215,000 miles.
I've never had to change an injector, and the service histories did not show any changes.

Was the car running OK before his mechanic "had a go" at the injectors ?

 

[runningman]

car was running smooth as silk prior to bad starting (knocking its head off)one morning, no symptoms it just started to knock suddenly, so had injectors serviced by a so called injector mechanic.
The car is approaching 16 years old, and my dad bough it 5 months ago with 44000 genuine miles on the clock, its now on 48500.
Maybe it was just waiting to happen, as car had seen very little use. Then all of a sudden its getting used everyday. ??

hoping Mercedes are right and it is the injectors, the mechanics that looked at it are almost certain that it is.

 

[Dieselman]

Sudden knocking sounds like either an injector started dribbling or the timing gear jammed.

A week and a half ago, I moved my 300TD to pastures new with 206k miles on. It has since done another 1200 miles.

The injectors are original with no work done and smoke emissions are virtually none existent.

 

[johnsco]

These engines are amazingly-long-lived.

 

[runningman]

the saga continues. fitted brand new bosch injectors this morning and you guessed it! engine still knocks.?????? it must be faulty lifters as I done everything else.

Dieselman. can you explain 'jammed timing gear'. do you mean the gear that drives the second cam or a gear inside the pump? or something else. its driving me mad.

 

[runningman]

replaced injectors this morning with brand new bosch ones, and its still knocking.
I can't think of anything else it can be now except for faulty lifters.

Dieselman. you say it could be a jammed timing gear, do you mean the timing gear on the second cam or inside the pump or something else?

 

[runningman]

doing a compression test tomorrow, what should the compression readings be?

 

[Dieselman]

doing a compression test tomorrow, what should the compression readings be?

At least 400-psi/ 27-Bar.

The pump timing gear resides inside the timing case and drives the pump directly.













(Oops. Another post onto the count for BruLan and Del to witter about... )