AKE engine problems - rocker arms keep falling off

[Alski2009]

Hello Audi Diesel Guru's.

I desperately need your help. My 2002 Audi allroad 2.5TDi V6 (152k miles) has been off the road for some time now. It's suffering from alsorts of problems. The oily bits mainly down to the longlife service intervals. The garage have rebuilt the front end, and replaced the brakes (discs & pads), MAF, turbo, new injectors, new rocker arms, new pressure pads, changed the timing belt, thermostat, water pump, pulleys, tensioner, gas strut damper, auxiliary belt tensioner pulley/bearing and probably a lot more, but didn't replace the camshafts and only changed a few of the damaged hydraulic lifters.

I remember going to pick up my car. It was difficult to start. Cranking, cranking, cranking. It would eventually start in a cloud of blue/sooty smoke and was lumpy as hell to drive, and there was a very loud ticking sound coming from somewhere in the right hand-side head. I shouldn't have accepted the car, but needed it for work. Foolishly i'd paid for the work and drove away.

Two and a bit months ago we went to the Lake District. Something didn't feel right on the way up. At around 2500rpm there was a slight hiccup, almost like a mis-fire. 2 days before we were meant to drive back down the car dropped a bunch of rocker arms and pressure pads. We'd crawled back to the cottage, on what felt like 2 cylinders, so we could get our things ready to be recovered to London. A pool of oil was left infront of the cottage and 8 hours and 3 recovery lorries later we'd made it to the garage in London.

The prognosis is the camshafts were so worn that they couldn't hold the rocker arms in place. Whilst driving back to the cottage 3 pressure pads had also fallen off and were lost in the engine somewhere. They'd later found 2 of them, but there is 1 more in there somewhere.

I'd picked the car up last Friday. It was lovely to drive. Sounded just like any other 2.5 V6 TDi engine i've heard pass me on the road. It was so eager to pull and felt like a different car. The power seemed to come in a lot quicker too. Within 5-10mins it was at 90degrees operating temperature, unlike before when it hardly moved above it's position of rest. The only thing that was different was the oil temperature would always read 80degrees, now it reads 100degrees. And since the recovery service had wrapped the strap around the anti-roll bar and pulled it up on the lorry, something in the n/s/f is clunking and there's a creaking sound with any steering input. I've been told to limit the revs to 2500rpm and allow things to bed-in for the next 1000miles.

2 days ago i was stationary in traffic and the engine cut-out. I'd restarted it and it was lumpy as hell. Here we go again. I'd managed to drive all the way across London to the garage. I've just spoken to the guys at the garage and one of the rocker arms had fallen off. As a precautionary measure they'd ordered a new rocker arm and hydraulic lifter from Audi. Bit of a nightmare getting it sent over, but as they were fitting it they'd heard another rocker arm fall off. As a gesture of good will there's no charge for the labour, but suggest replacing the other 23 hydraulic lifters.

Is there something they're not doing right? Is there something an Audi Master Technician would have a jig or tool for setting everything up? Is there some inside information that i can get to the garage? Or am i just unlucky? I've just read back this post and it seems crazy to have replaced everything but the hydraulic lifters. Tst tst tst. It makes sense that they are the only things that are holding the rocker arms up against the camshaft lobes.

Can anybody help me or do you have any advice? I wish i'd found this forum before i went to the garage as i'd have contacted Adamss24 to do the work. Since the warranty is with them i'm in their hands. Thank you.

[fjtwelve]

You have just had a very similar experience to me. Moral - if you are going to do the top end do the lot - hydraulic tappets, rockers, cams. The tappets are about £6.50 each so its hardly expensive, its the labour to get at them thats expensive. The first rebuild they replaced the cams, but not all the lifters and none of the tappets. Second time around after the cams started to wear in 12000 miles, they did everything. I've done over 3000 miles since the last rebuild and caned the arse off it, completed the remapping (well almost) no problems yet holding hard to this wooden desk. My thread is further down this forum.

[Alski2009]

I agree, knowing whats involved to get to those parts it would have been better to replace the entire top end as you've said. To mix new and old parts in such a precise system is madness. I'm just concerned with the rocker arms falling off. Maybe i've got this wrong, but the rocker arm sits on the pressure pad, which is driven by the camshaft lobe, which is held up by the hydraulic lifter right? Looking at the image at http://evvk.1g.fi/kuvat/Diudi/venaka...i/SDC10350.JPG. Doesn't the rocker arm act on the valve/valve springs? So there are forces keeping it in position from above and below. Where do the hyrdaulic lifters fit in the system?

I have just found an American Hotrod thread. http://www.hotrodders.com/forum/hydr...ers-34448.html I have copied some of the text out below.

'... Yesterday, I readjusted my lifters. Initially, I had adjusted the lifters while the engine was running to 1/2 turn in after they quit making noise. Then I read on the Comp and Crane cams websites how to do a static preload on the lifters while the engine is off. That is what prompted me to redo mine. I found out that even though I had adjusted the lifters 1/2 turn after quiet, that actually in a static situation, they were all adjusted to zero preload. Which means that I had to tighten down the lifters an additional 3/4 to 1 full turn, approximately 7/8 to be on the safe side, to get the required preload. Did I increase the lift I am experiencing or is my pushrod just further down into my lifter?...'

Are the V6 TDi lifters adjustable for pre-load, etc? Is this why the rocker arms are falling off? Or are they self adjusting? Another section from the thread.

'... The preload, for the most part, does not affect the overall lift of the cam. It just gives the lifter some working room. If you do happen to over rev the engine, the lifters will usually "pump up" ( the oil fills the lifter all the way up including the preload distance) and the valves will float, as in not completely close. This can be a good thing as it will keep the engine from going balistic and making a mess in the street. Also, if you over rev the engine, the springs will probably not be able to keep up and that will limit the rpms too. Most stock lifters and valve springs will "float" around 5 grand, which is pretty high for most stock engines...'

I'm going to ring Audi.

[Alski2009]

The Audi Master Technician was super helpful. He'd said to fit the rocker arms you have to fit the camshafts first, then compress the valve springs and finally fit the rocker arms. The hydraulic lifters are not adjustable for pre-load but do need to be filled with engine oil before installation.

[Alski2009]

24 hydraulic lifters later, a new tensioner and new injector seals and i've got my car back. It's low in power throughout the entire rev range. The 2.5 V6 TDi engine isn't the quietest engine, but there's a continuous low frequency grinding sound when it is first started up from cold till it warms up or a blip of the throttle soon gets rid of it. From inside the car it sounds like it's the N/S bank. I hope it isn't oil starvation. The oil pressure was checked and it was reported to be very good.

The engine sounds a bit more clackety. Large car diesel engines always have a slightly muted clackety sound (BMW 3.0d, Audi 3.0TDi, MB 320CDI), but my engine is much more pronounced. Almost like a Peugeot 106 XRD a neighbour used to run. I used to be able to cruise along at 30-35mph in 6th gear and press the accelerator a bit to increase my speed, but if i do that at 1000rpm the engine seems to mis-fire and starts jerking/shuddering like it had dropped a rocker arm again and i'll have to change down to 5th or 4th. Just before the last repair to replace all of the hydraulic lifters it was running very well. There was so much grunt. Now, if it hasn't dropped another rocker arm, then perhaps it's an injector seal or seals. I've been trawling the InterWeb and it seems the injector seat needs to be re-ground before installation of the new seal. AND, it seems that not all injector seals are the same - some have an extra ring of metal to sit in a groove cast in the head to provide a better seal. Some seals are too thick or thin which affects the position of the injector spray angle (TDI Club Power Enhancements thread - do you smoke with new nozzles). If it has dropped another rocker arm, wouldn't it be noticeable throughout the rev band? Not just 1000-1700rpm? Once it's on boost it goes quite well, and you can hear the turbo whistling. I'm limited to 2500rpm for the next 500miles, but it does sound quite nice at 2500rpm. I've missed that v6 warble.

All the test drives by different drivers have taken their toll on my poor clutch. The clutch is starting to slip - pulling away in 1st has that all too familiar jerking in the drivetrain, and sometimes in 2nd, as the nearly worn clutch plate grips and lets go. I'm going to speak to the garage about this. They've also cracked my engine cover so one of the rubber grommets is no longer attached, my n/s headlight has condensation in it, they didn't put it Jack-mode, so it's sat on the lift for 8 weeks with the suspension dangling in the air and now my n/s front suspension is creaking and squeaking. There's also a knocking sound when applying power. I've asked them not to leave it in the lowest suspension setting, as it can damage the airbags. Everytime i've gone to see the car it's been sat in the lowest setting. Arrgh!

She needs to go to the bodyshop for some repairs tomorrow. I've told them the heads have been re-built and to please take it very easy with her. After she's been sorted she's off to the garage again. Anyone recommend someone to change the front suspension airbags in the London area? I might opt for Arnott's Generation II allround and maybe their version of the Bilstein Gas dampers. The Audi World Tech Articles make it look quite easy so i might try doing it myself. I'm trying to get as much information as i can on removing the pinch bolt. Nightmare job.

Oh, anyone used Mr Clutch? Some of the online reviews aren't very good. It's either the DMF or a solid lightened flywheel. Adams24 - would you be able to do this for me?

I've spent so much on the car, i'm thinking about trading it in for something else, but i've changed nearly all of it. It'd be crazy to start all over again with something else. Or would it be better to walk away now?

[Mudplugger]

From the way they've treated your car, it sounds like the garage (and definitely the inexperienced mechanic that's been working on it) is of at-best dubious competence.

The way you describe the lack of power at the bottom end, then getting stronger as the revs rise, almost sounds as though the cam-timing has been altered. I don't know what's involved in changing the hydraulic lifters, but is it possible that the cambelt could be a tooth out (perhaps on just one bank) as a result?

I think Mr Clutch or anything similar is likely to be as good - or bad - as the individual mechanic you are (un)fortunate enough to get working on your car. If it was me, I'd be asking folk on here for a recommendation of a garage in my area that is experienced with VAG products.

And yes the drivers that get behind the wheel of your car are often brutal and incompetent kids. I well remember hearing my M5 hit the rev limiter in 1st with the child that was collecting it for service at the wheel, and on another occasion a kid (that wasn't suppoed to be driving customer's cars) from a local garage took a customer's GTI out for a play and crashed it into my parked car. Personally, I wouldn't trust any of them!

[Alski2009]

Happy Christmas everyone. Yikes, I'd forgotten to come back with an update. There was a weird vibration at all RPM. Most noticeable at idle speed, just a constant rattling like a panel was buzzing and the engine was low on power. 3rd gear corners were a struggle and i had to change down into 2nd. It turned out to be a tensioner has given up, luckily the timing was ok. Phew.

Shortly after I'd picked up the car again, sitting in traffic the all too familiar clunk and it was running lumpy again. So took it back to the garage. Had a phonecall from the garage after pulling off the rocker cover(s) and a single rocker arm had come off. Told the garage to fit a new hydraulic lifter, rocker arm and lash-cap and change the oil for Quantum Platinum and new oil filter.

Since then i have covered 6000 miles. Apart from a small oil leak (rocker cover gasket) wasn't replaced as the garage almost expected the car to keep coming back, the car is running ok. There's a bit of clunk/knock from the left bank on cold starts, then runs a bit lumpy and then settles down. The garage have checked under the rocker cover using an endoscope and report that everything is ok. I have heard it may be the glowplugs as it's a bit lumpy starting from cold. The garage are going to look at it for me in the New Year.

Other updates:
- I have a creaking sound coming from the N/S/F suspension and when i'm turning the steering wheel.
- A strange stuttering effect when i'm driving over badly surfaced roads from the N/S/F. I've been told it's the lower control arms as i get a little rumbling when turning into corners. The wheel bearings were replaced Nov 2009.
- My rear wash wipe has stopped working and there is washer fluid all over my toolkit, air cylinder and rear lights.
- My D/S heated washer jet shows 0.04Volts (+ve Green/Black, -ve Brown). The N/S shows 14Volts.
- It has just started to clunk a bit during gearchanges. Very jerky. Maybe the rear diff mount. Any experience with the Apikol Diff Mounts?
- The plenum chamber was full of water this am. Luckily caught it in time, stripped everything out and cleared out all the crap stuck in the rubber grommets.
- N/S HID headlight has a slight haze of condensation most mornings. I've packed it full of dessicant sachets and will set about removing the headlights and baking to soften sealant and re-seal. Read somewhere that the Honda sealant is the best. And not to use the vinegar smelling sealant as it will damage the silvered coating and projector lenses.
- Friend had Goodridge stainless steel braided hoses installed on his Civic 2.2tdi, the pedal feel is unbelievable. Looking to upgrade soon.
- I'm fedup with my seats after sitting in the Type R upgraded seats in Civic 2.2tdi. Love a set of RS6 or S6 Recaro's.

Note: My clutch and Dual Mass Flywheel is holding out. I think it is designed to slip during harsh starts. If the braided hose helps with the brakes i may get a kit for the clutch.

[adamss24]

When you have a few spare minutes and you in N. London then give me a ring mate, i wanna see what's wrong with it ! Regards, Chris- 077 89912128.

[Alski2009]

CHRIS! Many thanks. I have been meaning to ring you for a consultation. I'm hoping you can help identify some of the problems and perhaps help me fix them. Unfortunately i have to work over the next few days. Maybe i can come to you in the New Year and you can take a look? Thanks.

[adamss24]

No problem mate, give-us a ring a day or two before so i'll make time... Cheers !