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galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

Hi everyone. I have a Galaxy with the PD Tdi engine fitted. It runs smoothly, no rough idle and pulls fine.Its got 152k on the clock with a PSH. Ive personally maintained it for the last year.

After a run from blackpool to glasgow i noticed a very loud tapping, almost like a very loud tappet on a petrol engine had started. It is very loud from the top of the engine and seemingly a little from the right hand side.

The strange thing is when im driving it it never disappears, idling or under load. Even after an italian tuneup. It DOES however disappear when engine braking, which is wierd.

I only just serviced it about a month ago and used dealer recommended oil along with a genuine filter.

I have had the rocker cover off and cant see any immediate wear on the followers or damage on the camshaft lobes, although some of the lobe edges seem sharp. I intend to remove the camshaft on thursday and inspect it, the bearings and followers.

VAGCOM scan clear.

Any immediate suggestions? If i just go ahead and replace the shaft, followers and bearings should this fix it?

galaxy 1.9tdi PD - loud rattling from PD diesel engine - Peter.N.

The engine braking is a clue, that would be when there is no fuel being injected so it will probably be a faulty injector

galaxy 1.9tdi PD - loud rattling from PD diesel engine - Roly93

The engine braking is a clue, that would be when there is no fuel being injected so it will probably be a faulty injector

Seconded, sometimes if you are driving slowly with the window down, you can hear the diesel clatter go when you release the throttle. If this is happening with your noise it is almost definately one of the injectors 'hosing'.

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

wow, that does make great sense. would there be a way i could narrow it down to the specific problem injector?

I have a full version of VAGCOM, ill have a search to see if theres a way to query the injectors and monitor their performance, like the live timing.

galaxy 1.9tdi PD - loud rattling from PD diesel engine - 659FBE

If the camshaft and valve followers (bucket tappets) are in good order, your symptoms sound like injector noise as has been suggested above.

Before you take this engine apart, there is one simple check to make when the valve cover is off - the ball pin clearance settings for the unit injectors.

The Bosch unit injectors and the roller cam/rocker system for actuating these are all highly reliable and trouble is very uncommon. If you do not have access to the setting procedure, the following is a quick and simple way of achieving a reasonable result without any special tools:

With a cold engine, on each cylinder in turn align the inlet valve cam lobe to be central to the pin of the roller follower for the corresponding unit injector cam. This will (for a particular cylinder) set the unit injector at maximum stroke. The "proper" way to do this is to use a dial gauge to detect maximum rocker travel. My method is very close indeed.

Slacken the locknut on the fully depressed rocker and screw the ball pin fully home - it will feel pretty solid. Slacken the ball pin by rotating it anticklock 225 degrees and lock with the nut. Repeat for the remaining cylinders.

Do not tear down a PD engine unless you have a really compelling reason to. There are many torque to yield fasteners and other highly stressed parts which don't always take kindly to being disturbed. If you remove the camshaft, note that it has bearing shells which will require renewal.

I would be very interested to hear what caused this fault - a wide ball pin setting on an injector would be "nice".

659.

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

Thanks for your reply, i appreciate it probably took a while to post.

I have a bit of a question, i presume the locknut is the approx 13mm nut on the injector side of the rocker arms, but whats the ball pin? is this like a screw thats under the locknut?

If a locknut is in place surely its there to stop precisely this?

galaxy 1.9tdi PD - loud rattling from PD diesel engine - 659FBE

The locknut is indeed on the injector side of the rocker and its function is to lock the ball pin which is threaded into the end of the rocker and which presses on the plunger of the unit injector - inside the big spring. The ball pin is ball-ended at the injector end because the rocker pivots and the injector plunger slides.

Think Morris minor tappets, the arrangement is precisely the same.

After 100k odd miles inside a diesel engine there's always the possibilty that the locknut has loosened and the pin has unscrewed a little - giving the grandmother of all wide tappets. If the pin unscrewed completely, there would be no fuel from that injector.

If the clearance is only a little wide, VAGCOM won't necessarily reveal this as there is a generous allowance on this engine to enable it to be fully supplied with fuel over a wide timing variaton + the "KW" error associated with the cambelt installation.

659.

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

Thanks ill have a look.

If this was the case would it rattle when engine braking?

Im tempted to unplug injectors one by one to see if it stops the rattle while im there.

Edited by foshizzle on 16/08/2011 at 00:18

galaxy 1.9tdi PD - loud rattling from PD diesel engine - 659FBE

The PD engine cuts the fuel on the overrun. The injector solenoids are not energised and the fuel is discharged at relatively low pressure to spill.

Mechanically unloaded pump plungers will not make anything like the noise of a pressurised plunger when struck by the ball pin. Worth a look.

659.

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

Hi no such luck im afraid, all of the locknuts are sat at their specified torque. So i imagine its a duff injector, how do i find out which one?

I ran a scan through vagcom, looking at 01 ENGINE 023 injectors, and 3 were sitting at about 32-35 and one was at 20, which seems to confirm an inector is on its way out.

Is there a way to trace the duff one under the bonnet? Its that loud i dont think i can locate it with the engine running.

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

Sussed it. Feel like a bit of a pleb for not noticing it the first time i had the rocker cover off, but its a proper 'jeeezus' moment. I decided to check all the torques on the bolts to ensure nothing had come loose. That was when i noticed that one of the four bolts holding one of the injector rocker rails on wasnt there!

Then panic set in - if it wasnt there.. where the feck was it. Out of sheer and blinding luck, i felt right down into all the oil ways and nooks in the head and found it, and managed to get it out with a circular magnet attached to some strimmer wire (didnt want more metal flying about in the engine).

One lucky escape.

Thing is, looking under the head of the bolt i found its flush. The bolt left in the engine is sat about 2mm into the hole where it sits. So i started fishing again and found nothing more after an hour. So i took the oil filter off, and again came up with nothing. I intend to get the other three bolts off and see if the head of the bolt matches up to the rest of it. If not, ive got about 2mm of metal kicking about in the engine somewhere and its sump off time soon as it stops raining.

Im aware these are stretch bolts and have to be replaced each time, so im *hoping* that it does match up once i get to it. Four new bolts on order from VW cost £5.03 each +VAT. Heres some horrible pictures:

img696.imageshack.us/img696/7651/imag0410d.jpg

img143.imageshack.us/img143/5913/imag0411sv.jpg

img838.imageshack.us/img838/9590/imag0412.jpg

img268.imageshack.us/img268/4310/imag0413u.jpg

Edited by foshizzle on 16/08/2011 at 18:08

galaxy 1.9tdi PD - loud rattling from PD diesel engine - 659FBE

Thanks for the feedback - the original suggestion of a wide injector ball pin clearance was in fact correct as the rocker shaft would be lifting under these conditions, giving the same effect.

I hadn't bargained for a breakage though...

The unit injector drivetrain works under very high stress (note how beefy the rocker is) and as you correctly observe, the shaft securing bolts are one time use only. I hope there is no other damage to the engine - I would change the other bolt for the shaft as a precaution as there would have been a severe bending moment on it.

Assemble carefully and the engine should do another 150k miles - the original Bosch-fired PD is a gem. It's a pity VAG/Siemens wrecked it.

659.

Edited by 659FBE on 16/08/2011 at 18:53

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

Thanks for the reply, ive ordered the full four as im going to have to take the rocker arm off in order to remove the snapped stud.

Ive also heard that people have stripped the threads off the head torquing these down.. have you ever encountered this?

galaxy 1.9tdi PD - loud rattling from PD diesel engine - 659FBE

The figure I have for the rocker shaft bolt fastening is 20 Nm + 90 deg (new bolt).

As a general point, I have found that in many cases when working on VAG vehicles, the stipulated "torque to yield" procedure will cause thread damage. The stud for the cambelt tensioner on the PD engines is a good case in point.

I could not advise you to deviate from VAG's specifications but at the same time I would urge the use of common sense. For an experienced operator, it's easy to tell when threads are about to pull and stop before damage occurs.

As with your rocker shaft bolts, the cambelt tensioner stud is threaded in aluminium and the stipulated tightening for its nut is 20 Nm + 45 deg. I tighten to 20 Nm with a torque wrench and then use a ring spanner. I usually stop at about 15 - 30 degrees.

I've never had one come loose. If the thread is damaged, it will certainly come loose.

I've seen too many cases of damaged threads on VAG vehicles to blindly follow the maker's procedures and so I don't - but I cannot reasonably advise you to do the same thing.

Best of luck.

659.

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

thanks pal, im just waiting for VW to come up with the goods and then ill report back if it all goes to plan.

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

Ive found 20nm +270deg.. which is the correct one?

galaxy 1.9tdi PD - loud rattling from PD diesel engine - 659FBE

Time I think to make a very careful check.

I can tell you from experience that VAG documentation is not free of errors - some serious.

20 Nm + 270 deg sounds very unlikely for such a short M8 bolt. I think that tightening to this figure would be a very risky strategy - the thread depth in the aluminium head is not great. If you have heard of thread damage occuring at this point, it could well be the result of a VAG documentation error somewhere that has caught others.

Go carefully indeed - I'd stop at 90 deg first. If you get an authoratative value perhaps you could post it here - I've assembled these to 20 Nm + 90 deg without problems.

659.

Nm = Newton meter
nm = nano meter

galaxy 1.9tdi PD - loud rattling from PD diesel engine - foshizzle

I got some interesting information from

www.myturbodiesel.com/forum/f21/camshaft-installat.../

(you may neew to register)

It basically says that the triple square bolts were supersceded by non stretch allen bolts, with a different torque setting.

From that site it gives OEM stretch bolts 15Nm & 90deg, ill err on the side of caution and go with somewhere in the middle :D

galaxy 1.9tdi PD - loud rattling from PD diesel engine - 659FBE

It's interesting to see that there have been revisions in this area.

I think if I were in your position I would talk to a knowledgeable and interested Independent who has seen a fair few of these engines and who is aware of the updates. The problem with the dealers is that they are programmed by VAG to operate like zombies and any errors just get repeated, let alone reported back. The interest factor is generally not there either, so jobs are seldom optimally done.

Use EKTA to make sure you have the latest revision of the bolts - EKTA seems to be one error-free area of VAG's system. Note the part number and then do your research to get the tightening procedure.

The loadings in this area are very substantial - injection pressures on a PD can approach 2000 bar (hence the efficiency) and there is almost no margin for errors. You may now consider replacing all of the rocker shaft bolts.

659.

 

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