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Old 18th November 2018, 05:27 PM
Versace Versace is offline
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Default Chain tensioner pad replacement 40V engine

Hello guys; I am experiencing some semi-cold strart rattling-knocking but it's not always present. If I start the car when going back from work, sitting 8-9 hours it does it. If I leave the car sit fot 24 hours it's okay.
I first changed out the oil check valves sitting in the upper "oil sump" under the Intake manifold, it didn't do the trick. We changed it as we were removing the manifold because of the LPG.
Few days ago I made an oil flush, first added a litre of an ATF and drove for 100kms, then the Liqui Moly Pro Line Engine flush, 15 min of Idling before the oil change. After we drained the oil and changed the filter I added some cheap 5w-40 (Mannoil) just to flush the engine and ran it for additional 15min again not to be contaminated with the Flushing agent and ATF; as it's always at least 0,5L leftover oil in the sump an 0,5L in the engine. Then we removed the sump for inspection and possible sludge removal and contrary of my expectations, it was pretty clean (for 400.000km engine!). The only problem we found in the sump were broken parts of the chain tensioner. (final topup after the "cheap oil" drain was Mobil 1 0W-40 with new Mann Filter)

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Now as my chain tensioners wor flawlesly I'll only replace the pads, but as I'm reading the world's forums, it's quite a job! As an experienced tech guy I'm able to do this at my friend's shop with his help but I need to know what exactly I need to do, what are the torques for the cam holders etc... And I don't own a bentley manual! If someone has it' I'm willing to pay for few pages on this thematics.
So my questions are:
Has anyone done it; has anyone some information about the torques on the bolts; in what position has the engine to be for this "operation" etc...
I know I need tensioner compression tool, it's only few EUR on the ebay...
I could replace the upper pads without removing the cam tensioner and cams but it's a bad idea as they Will fail eventually...

Thanks for any kind of help!
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Last edited by Versace; 18th November 2018 at 05:35 PM.
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  #2  
Old 18th November 2018, 08:23 PM
MikkiJayne MikkiJayne is offline
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If those are pieces of the chain tensioner pad in the sump then do NOT start that engine again until it's fixed If the pad breaks up completely its bye bye engine as the inlet valves will hit the pistons.

I'll go and find you the info, and also a thread where I show the job. You need two people to do it with the engine in the car - one to hold the cam, and one to put the tensioner back in.

Essential tools are a good quality T30 torx bit, a small torque wrench which can do 5Nm, and the camshaft locking tools, and of course the tensioner tool which usually comes with the tensioner pads. You have to take the cam sprocket off bank 2 to do it, but you can leave the exhaust cams in place.

Edit - this post here has most of the info you need plus a video of the job on the V6: http://forum.a8parts.co.uk/showpost....0&postcount=73

This is obviously with the engine out where it's much easier, particularly since the engine can be rotated so the head is level. With the head level its possible to do it single-handed, but with the engine in the car and the heads at 45* you need the second person to hold the cam.

Factory procedure shortly...

Last edited by MikkiJayne; 18th November 2018 at 08:39 PM.
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Old 18th November 2018, 09:10 PM
MikkiJayne MikkiJayne is offline
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Procedures are attached. There is a slight difference between the two heads - basically the number of chain links between the notches on the cams. As long as you mark them carefully before you take them out the number of links is only needed as a reference. If you're careful (and have a second person) you can do it without removing the chain from the inlet cam.

As I mentioned, I leave the exhaust cam in place by leaving cam caps 4 and 5. Remove 1 and 2 though to give you space to lift up the inlet cam and slide the tensioner out. It won't come out with 2 in place.



Most important when putting the cams back with the engine in the car - make sure you keep tension on the bottom of the chain at all times by holding the inlet cam tight. The chain likes to kink underneath the tensioner and then you can't get the cam back in its journals. It should just drop in place. If it doesn't, or the cam caps are too tight then take a sip of coffee, remove the tensioner and start again. When you get it right it will all just drop in.

Also, its worth getting some M6x50 bolts to seat the first two cam caps. Use these to hold the cam in place, but don't over-tighten them since obviously they are too long. Once the cam is settled, put the other caps on it and then replace the M6x50 with the original M6x40s then tighten them down fully. I have found that there isn't quite enough thread on the original bolts to start pulling the cam down and you risk ripping the threads out of the head. You'll see what I mean when you get in to it.

Good luck!
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  #4  
Old 18th November 2018, 09:20 PM
Versace Versace is offline
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Thank you for your answer! The car is driving arround with this pad culprit for more than one year now!!! I'm servicing it as soon as possible! I have to get the car to the shop where I will make this, 150 km away!

You are really heplful, I don't need to buy the manual now for this job! I already ordered the pads and the tensioner tool!
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Last edited by Versace; 18th November 2018 at 10:03 PM.
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  #5  
Old 9th December 2018, 09:19 PM
Versace Versace is offline
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The job is done! It definitely isn't an easy task but it's doable without any major problems. The eingine was put in the TDC and I removed only the Intake cam, and just to confirm, the adjuster comes out without the need to remove both cams!!! One just needs to detach the toothed belt cover to slip the adjuster past it. I replaced the chain tensioner pads and the valve cover gasket. The problem itself insn't resolved yet as I get the knocking at the cold starts again so it's the adjuster not holding the oil pressure quick enough. It's the driver's side adjuster as the passenger side had to be replaced by the previous owner max. 2-3 years ago as it's looking ike brand new. Now for the question. Anyone tried the ebay adjusters? I'm realy not into paying 750 EUR for OE Audi one.











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Old 23rd March 2020, 07:37 PM
Versace Versace is offline
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Anyone got a clue why I do still get the hard knocking sometimes when cold/hot starting? Both tensioners were replaced...
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Old 23rd March 2020, 08:22 PM
MikkiJayne MikkiJayne is offline
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Did you replace the tensioners with genuine units or just change the pads? The right hand (bank 1) tensioner fails when it eats the filter gauze which then jams the cold start pin. The cold start rattle is the driver's side cam jumping about until the oil pressure is enough to tension the chain. Failure in the bank 2 tensioner is rare I think - of the engines I've dismantled, they are usually ok.
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Old 25th March 2020, 01:56 AM
Versace Versace is offline
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Both tensioners were replaced. Bank 1 is an OEM unit, replaced 4 years ago at Audi Service, (About 120.000km ago), the bank 2 that makes the noise, was replaced by myself about 80.000km ago with a brand new (FEBI I guess) unit (I replaced the Tensioner only, wothout replacing the chain!)
When installing the LPG, I also replaced the two oil check (one way) valves inside the block under the intake manifold (They sit in an upper oil pan).

I ran pretty much all possible oils as I thought it was an oil issue:

Mobil 1 0W-40 (10.000km)
Aral High Tronic 5W-40 (10.000km)
Mannol Extreme 5W-40 (10.000km)
Mobil 1 5W-50 (10.000km)
Ravenol RCS 5W-40 (15.000km)
Ravenol RRS 10W-50 (15.000km)
Mobil 1 Super 3000 X1 (10.000km)
.....

No luck.

And it's not just rattle. The chain is banging like crazy for few moments. There is no way I know when it's going to make it.
I can leave the car over night and it bangs the chain, or leave it for few days and it starts smooth.
I can leave it for 25minutes and it does the same. I have no check engine lights except now and then for a catalytic converter (value below treshold) which has nothing to do with this problem. The car goes and pulls like it should, I would say better than my 4.2 D3!
And I drive it alot. 150km daily at least. Now it has 467.000km on the clock.
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Last edited by Versace; 25th March 2020 at 02:09 AM.
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  #9  
Old 25th March 2020, 10:53 AM
spannerrash spannerrash is offline
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I don't know of any good quality after market manufactures of these tensioners. If you fit anything other than oem then I think you did OK to get 80,000k out of it. I changed mine a couple of years ago and after doing lots of research I couldn't find a quality after market unit. I doubt febi have done one. If you fit after market, you probably fit Chinese.
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Old 25th March 2020, 03:42 PM
Versace Versace is offline
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Yes, probably chinese.
The wierd thing is, that it is the same from the first moment I replaced them. It did never get any better nor worse.
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