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Labour time for camshaft tensioners on 40v 4.2 A8????
Hello to all,
I have posted this in the D2 and C5 forums despite having a D3 as they share the same chain setup.
I have recently got a seemingly absurd quote for a job on my 2006 D3 A8. Skip to near the end if you don't want to read the lenghty preamble.
The situation is this:
i noticed in the last few weeks there was a strange noise when i accelerated, perhaps like a heat sheild but semi consistent so i brought my car to a shop. The only thing that i was really concerned about was my timing and serpentine belts as the they would leave me stranded (the former ruining the motor).
So the shop tells me that the timing belt is extremely loose ( to the point they could spin the water pump by hand) and that it could skip timing at any time. The belt was done 70000 kms~ and 4.5 years ago according to receipts when i purchased the car. It currently has 210000. The labour time they gave me for the belt seems reasonable at 7.5 hours.
I noticed in the last 1.5 years i have owned this car it rattles for a few seconds (never more than 5) on cold start, which i presume to be the camshaft tensioners. They are silent after intial startup. I have seen many posts about the the two teflon or plastic pads wearing or even fracturing. I suspect this would be disastrous should it occur as should the chain contact the metal underneath the metal fragments and shavings would cause serious damage around the engine. I have also replaced the check valves in the valley pan for the oil lines going to the tensioners, it did not make it any better.
Now as timing belt removal and everything going along with that is required to get at the camshaft tensioners i figured i would address them at the same time.
My first issue is that the OEM tensioners are absurdly expensive the cheapest i could find are 1000$ CAD each. I have found many forums saying to stay the hell away from aftermarket tensioners as the chinese ones do not last at all.
I did find these which claim to be "OE Supplier" for 250 USD each. When i enquiried who makes the the part they said they had no information as the part was "brand neutralized". He did however state they are made in Turkey. They do at least from pictures seem to look exactly like the OEM ones. Here are the links:
Now should i use these or just replace the pads and chains? I find the OEM ones are too expensive as I could buy a spare engine for what they cost.
The other main problem is that they quoted me an additional 27 hours (!!!) to do the camshaft tensioners or 34 hours total with the belt which i find very hard to believe. I almost think they got this car mixed up with the timing chain variant of this engine in the S4, Allroad, C6 A6 or newer FSI for this part of the quote. Can anybody who has done the job, had it done or has knowledge of it comment if this is accurate?
I think if I'd done it a few times I could do the tensioners in 3 hours per bank with the timing belt already off. It took me a lot longer than that to do but I'd never done it before and I was trying to finagle the tensioner out without pulling both cams, nears as I can tell you cannot do that on this engine.
I just did the pads and if I did it again on a car like my 2001 scruffy and 190K miles at the time, I'd do the same. My engine still clacks a few times on dead-cold startup but it'd done that for years and years. I am not concerned. It's not as bad as it was, I suppose with new pads there is not as much room for the tensioners to collapse down. If the car was nicer I might have spent $500 on tensioners, I would not try the cheapo ones. My chains were fine.
The kits that come with tensioners, pads, gaskets, etc. are probably a good value even if the tensioners are discarded.
I also did the bufkin pipe as I had a coolant drip down there, that took a while and required fabricating some custom allen bits
Afterward I took my car on a long, fun roadtrip so I suppose it was worth it but I'm not entirely sure. I only spent a few hundred bucks but it took a long damn time. If I had been paying for labor I would have junked the car.
The shop is probably wrong about your belt, they probably just caught it with the cams in a particular phase where there is a lot of belt slack at the pump, or they have a boat payment due. If you can localize the noise it's not hard to pull a cam cover and see what's up in there, and if it's the LH top pad like on my car I think a new pad could be finagled in. If you are at 210Km I'd be surprised if you had a cam chain pad failing.
I suspected those labour times might have been way off, it is likely some piece of estimator software that is telling them that. I don't think the noise is the pad being bad on the tensioners as i think it would make much more noise at idle. Though when i do the belts i may replace all the pads as a precaution and keep running the old OEM tensioners.
As for the belt, I am a little suspicious of that not being bad as well. I did see a few forums saying after engine shut down as long as it was tight in these areas it was alright.
I found this post saying something similar yesterday:
What concerns me is they have done a few belts on touaregs before and i would have thought they would have noticed that. Maybe it's possible they only checked the top. I will have to do some furthur investigation. Maybe geting them to check other areas or gambling driving it to another shop for a second opinion.
Out of curiosity what pads did you use? I did see some in a kit on blauparts but they seemed much darker (don't know if that matters) than the OE ones.
That's a good thread both for the cam phasing causing scary belt slack and for the cheapo cam adjuster failures. First time I looked at my S8 timing belt I was really concerned by the slack in that upper run but it's all about if the cams are trying to flop over CW or CCW as that pulls slack into the belt. I recall there is a nice neutral spot with the crank 45 degrees BTDC and the cams half that, so just before the cam holding bosses line up, where the cams are not trying to pull on the belt much. At TDC there is a lot of force on the belt from the valvesprings. But like on a 928 there is a chill-out spot before TDC.
I do not recall what pads I got, I think I got them off Ebay and got one set with the adjuster tool and one without. If I did it again I'd probably get the big $150 kit that has the tensioner gaskets, valve cover gaskets, tensioners, etc. and send the new cheapo tensioners to sleep with the fishes. Seemed like those gaskets added up fast in cost, but maybe there is a cheaper option.
I retrieved the car from the shop and brought it home. I finally got around to pulling the cam cover off. What i found was the opposite of what they said.
The belt seemed significantly tighter on the water pump side, no way i could spin that by hand. Also more deflection on length going toward the crankshaft from the Cam.
Perhaps this is what you were saying earlier about the valve springs pulling on the cam CW or CCW depending on where it comes to rest in its cycle? Which would explain them finding the opposite side looser.
Here is a link to a video i took to quantify to some extent the tension on both sides.
The shop is way off on their times, these are tricky but not 30 hours tricky. I had a tensioner shoe fail last year during a warm start at a gas station in my former A8. They were getting pretty loud, and I didn't get them in time. I was lucky, the chains only skipped a tooth or two and didn't kiss any valves. I put in used tensioners I had laying around from a junk yard score, replaced the plastic shoes off ebay, and let her rip. It took me awhile, but an experienced shop would be able to get it done in a day. These cars can be easy to work on if you know a thing or two.
As far as Chinese tensioners, I will be installing a set of Spectra tensioners in my current A8L that is making noise now at 208k miles. I will install them over the Christmas holiday while I don't need the car. Fingers crossed...
So i was informed i will in fact need a belt put in despite being well before interval. Is there anything other than the chain and tensioner shoes to do while the cams are out for "while your in there" stuff?
I did as well notice in VCDS group 93 while one cam reads 0 degrees for idle stabilization the other reads -6.0. Unsure if this means the cam tensioner is on its way out or what. Maybe the new pads, chain or belt might help.
Also i think that the Bufkin guy may have taken down his site, is there any good quality alternative? I did find this one on ebay:
The Bufkin guy quit because of the knock-offs, I got one of the last few.
If I got a knockoff I'd maybe chamfer the O ring grooves but otherwise they are probably OK. Maybe get O rings from a reputable vendor. Yes it's good to do during a timing belt service, before it starts dripping.
-6 is not a crazy number. -15 to +10 is the range I believe and I have had some big numbers and an OK running car.
When I had a broken pad I had a P0022 Camshaft over retard Bank 2
11-28-2020, 10:01 AM
Labour time for camshaft tensioners on 40v 4.2 A8????
