Noisy Cam Chain Tensioner

[archerj]

I have just changed the leaking Cam Chain Tensioner gasket on my 2.4 V6.
I managed to do this without removing either cam shaft, simply compressing the chain tensioner with the special tool and then using the space provided by unbolting the CCT and lifting to the now slack chain.
My problem is this; The CCT/chain now sounds very noisy when idling, so i'm wondering if a) i've somehow damaged it. Or b) somebody else has experienced this and knows if the noise goes away/is a problem.

Note. I did not have to compress the CCT very hard at all, i simply turned the tool lightly and the CCT piston retracted. Hence i do not think i over compressed the CCT.

When i bolted the CCT back onto the head and released the compressing tool the tensioner sprang back immediately and took up the chain slack.

I didn't move the cams at all during the work.

When i first turned the car on the starter motor (before properly starting it, to double check that i hadn't interfered with timing etc)after putting everything back together i did so without the pipe between the airbox and air intake on the engine. This resulted in a cloud of smoke coming from the air intake, it also appeared to cough out some burnt oil residue/dust that i found smoking in the airbox grill opposite it. After bolting this piece back on and starting the engine it appeared to run fine. I took the car for a short run and when i lifted the bonnet later to check i had fixed the oil leak the CCT sounds very noisy to me. (I am assuming it is this, if anybody thinks otherwise let me know)

I think i've read that maybe the throttle body needs adapting because i've had the airtake apart whilst cranking? Would this affect the CCT. (Edit i'm discounting this because the revs sit perfectly still)

Because i didn't rotate the engine a couple of times by hand, have i somehow failed to prime the CCT with oil and then having the engine run damaged it before it primed itself?

Any experience or thoughts are appreciated

Regards
Ian

Now that i'm sat around getting paranoid, if the chain was a tooth out when i put it back together i'd know, right? Because it would sound terrible/explode/run terrible/etc.

[Crasher]

I would start by checking the cam timing, it sounds like one of the cams moved a tooth to me. It is impossible to fit the gasket incorrectly so if the timing is correct I think you have a faulty tensioner. When I have removed them, I always fit a new one as they are troublesome and I hate doing things twice.



If you have VAG-COM you can test the cam chain adjusters in Measuring Blocks 027.

[archerj]

Thanks for your reply,
I have Vag-com lite, so i'll try it in the morning. (And then see if i have to buy the full version. Oh the wife will be soo happy!)
Measuring block 27 is ctrl head, rear. Correct?

Once i've done this, i'll take the cam cover off again and re-check the timing marks on the cam shafts to see if they aline with their respective marks on the head when i've rotated the crank. I'll also check against the cam sprocket as well. I doubt i'll be able to see the TDC mark on the crank as i don't intend to take the bumper off. The timing belt has not been touched so i know this cannot have moved in relation to the exhaust cam, so it must be the inlet cam that is off, if anything. 16 pins mark to mark, with the exhaust mark being slightly off towards the middle is my understanding.

Do you know what the VAG part number is for the chain tensioner if i find my timing isn't out and i have to replace it. (i find it very hard to explain in english to polish parts departments what i need without my numbers ready!) The engine code is APS

I'll post my findings tomorrow

Regards
Ian

[Crasher]

No, Measuring Blocks 08, group 27 in Engine 01. PM me your engine code and email.

[archerj]

Hi Crasher,
I ran Vag com on my car but it came back with no fault codes found.
However as i only have a cheap cable and the shareware version i'm not certain that this is the case. it could just be that they don't like talking to each other.
The timing all looks spot on, although i guess the chain could have stretched abit. (It is currently on 170000 miles and i doubt it's ever been replaced?)

I took the valve cover off again and made a video of the tensioner in operation as the crank was rotated. The cycling up and down of the piston is around about 90 degrees rotation of the cam sprocket.
I also did video to record the sound it was making whilst running.

http://www.youtube.com/watch?v=-f9NsO_GsVQ
http://www.youtube.com/watch?v=x87x55OZa-I

I'm thinking that the reason it's making such a noise is that as the piston 'drops' down it momentarily looses tension before picking it up again, hence it rattles along? What are your thoughts? Does it look knackered?

If i replace the tensioner would you suggest repalcing the chain? Or is this not necessary?

Regards
Ian

[Crasher]

Read the info I am going to send.

[archerj]

Thanks for the info. VERY much appreciated.
Once i get hold of a better VAG COM cable i'll run another diagnostic.
What did you think of the video/sound? Would you say that with a knackered chain tensioner i'm almost certainly looking at the right source of the problem?

Until i fix it, am i ok using the car as a run around?

Thanks again

Ian

[Crasher]

I can’t tell much from the videos but the tensioner will behave like that without oil pressure. It does sound a very noisy engine, it makes me wonder if the oil pressure is low.

[archerj]

I'm taking it to a garage tomorrow to have a diagnostic done.
I'll post the findings, and then pester you some more.

Cheers
Ian

[archerj]

So a follow up.
There were no fault codes saved on the system.
The guy also went through the measuring blocks 1 to 29 and all the parameters were within tolerances at idle. However he didn't have a portable system so we couldn't perform a test drive to measure the variable valve timing 'on the move'.

I had the mechanic listen to the chain tensioner and he was of the opinion that it merely sounded it's age (162,000 miles) and that if it truely had failed it would sound different.

I recently changed the oil; I read in a post you made on another thread that they are sensitive to changes in oil, so maybe this is the issue.

The mechanic also suggested that because of the engines age i should have swapped to thicker oil. I've been using 5w40 for the last 3 years since i've had it. So i'm going to change it for 10w40. Maybe this will quieten it down.

He also told me to stop being cheap and use 98Ron Petrol instead of 95.

Whilst i'm at it, should i take the sump pan off and check the oil pump strainer? I've read about these blocking on the turbo's but no one's mentioned it about the naturally aspirated v6's. I'm sure that i can get at it on this engine without having to lift it or lower the engine mounts, so it shouldn't be the massive job that it is for the 1.8's?!

Ian