Housing next to Cam Pulley

[Bens313]

Hi All,

First time posting on here, probably many more to come as me and the Mrs both have MK5 GTI's!

Could anyone tell me what is the component I have indicated with big red arrows on the picture is and what it does please? Picture from google images. Whatever it is its pretty noise in my Mrs car.

Thanks,

Ben.

[pudding]

Welcome 

That component sir, is the housing for the cam sensor trigger wheel.  The sensor plugged into it is Mr Cam Sensor.

I doubt the noise is coming from that directly, but rather travelling down the cam from the other end. Possibly chain or VVT wear.

[Bens313]

Thank you and apreciate the speedy reply.

I probably should have added a bit of background. We got the car and it had a noisy cam chain, that and tensioner have been replaced and quietened down the car quite a lot. It got more noisy again over the course of a few weeks and my trusted mechanic said he thought it was coming from the left had side of the engine. It would need a new timing belt soon anyway so we decided to change that, tensioner water pump etc. Well he did that yesterday and hes said the noise is definately coming from the housing above. Like you i suspected that it might be becuase we didnt change that cam adjuster on the other side of the engine exhaust cam but hes told me its deffo not coming from there.

Some of the symptoms are:
P0340 and sometimes P000A (Which makes sense relating to intake cam position),
Rough idle but it runs great above idle
The noise i mentioned before which also goes above idle.

Thanks for the help!

[pudding]

P0340 usually means the timing is off I'm sorry to say, not the sensor itself.  The noise and rough idle are quite good clues.

Looks like the cambelt is timed correctly....no wait.....that's my engine 

That part arrowed cannot make a rattle noise as it's just the end of the camshaft shrouded with a cover.  There are no interference parts in that area.

I'm not trying to poo-poo your mechanic, but I'll put money on the noise travelling down the cam shaft.  Believe me, I spent 2 years misdiagnosing a rattle because engines are echo chambers.  My rattle turned out to be a broken VVT oil control ring in the chain cover.  That's how I know sound from that end can resonate down the camshaft 

The reason the noise goes off idle is because either you also have a broken oil ring (easily done when refitting the chain cover after chain replacement - don't ask how I know) and an increase in oil pressure silences it, or the base timing is off, causing a VVT rattle.

My advice - check the base timing.  Get the engine on TDC cylinder one and make sure the arrows line up as per the picture.  If that end is good, check the timing on the chain end. A *lot* of people get that end a tooth off.  It's not a criticism, it's just an easy mistake to make because there's a lot of slop in the cams when timing it up, in spite of using the proper cam locking tool.

Is the rattle worse when the engine is up to temperature?

[Bens313]

Good news is the engine is definately in time now as its just had new belt etc fitted so prehaps that will stop the P0340. It didnt come on on the way home which was a good sign.

Perhaps we will go back to the other end of the engine then. Would you recomend i ask him to take the cover off and change the oil control rings (Any link to them?) and if that fails have a look at changing the VVT unit on the end of the exhaust cam?

Car is much quieter when cold, only starts to really rattle when warm.

Shes got to use the car for work, im assuming this isnt a stop and park it up untill it can be adressed type issue now that its got a new chain and belt timed correctly.

[pudding]

Yep, exactly the same symptoms as mine.  Fine when cold, but when hot, a god awful racket that disappeared at approx 1300ish rpm.  Seemed worse under load when the VVT adjuster was trying to phase the inlet cam. I'm not 100% stating as fact it's your problem, but your issue is eerily similar.  It could be timing at that end, it could be the broken ring.  Both are easily done during chain replacement.  Good luck with it    Due to the P0340, I'm kind of leaning towards timing as it's a classic cause.

These are the pesky little oil control rings.

https://www.akstuning.co.uk/shop/home/345-genuine-camshaft-adjuster-housing-seal-set.html

And here is the broken one from my engine, which was the source of the noise. They are PTFE and extremely brittle and easy to break when sliding the cover back on.  You have to make sure the cover goes back on dead square and gently.  But yes, checking the chain end for timing is a good idea.



Also, get your chap to check the condition of the VVT adjuster.  If yours has very deep scoring grooves in it, like this one (also mine, I ended up replacing the cover and VVT phaser), that can also promote ring breakage upon chain cover refitting as the ring kind drops down into the groove and can snap when the cover is pushed home.  The only cure for that problem is a new VVT adjuster.

[Bens313]

Okay i will grab a set of seals and investigate that area. Are there any aftermarket VVT Phazers you would recomend? Try to avoid forking out the £400 odd pound if its not that or doing the job twice if i dont get one.

Thanks for all the help.

[Bens313]

Pudding, just seen that you mentioned on another thread a while back (Link below) that unplugging the VVT solenoid and listening to see if rattle stops could be a way to diagnose a faulty VVT phazer. Is this the little N205 valve on the cam chain housing? If so i will do this just as an easy check.

https://www.mk5golfgti.co.uk/forum/index.php/topic,131900.0.html

Ben.

[Bens313]

Well i went to unplug the N205 and you can see what happenend below. The plastic was already cracked to the point where i could see the copper before attempting removal and i suspect that it wasnt good before completely coming off.

I think ill start with this 

[LC5F]

Suspect that may well be your issue, lots of copper blue corrosion, so it's been cracked for a while - you may need to clean the loom plug.
I was intimate with mine back in the summer, at the time I thought it was a really daft design for the loom connection - with little or no gusseting to support, its as if they want it to break!

[pudding]

Oh dear! That certainly won’t be helping matters!

[Bens313]

Update:

Ive changed the N205 (Not genuine but didnt want to sink money into something that might not be the problem yet). The car is much quieter and the rattle i was worried about has all but gone. Im still holding my breath as it quietened down right after we did the cam chain too and slowly made its way back. If it does come back i think i will do those 3 oil controll rings next.

A couple of points to note though:

The car did throw an engine light between now and last post (Maybe 200 miles) but it wasnt a P0340, it was the P000A that i got a while back not long after the cam chain had been done. I did clear the codes after messing about with the cracked sensor a couple of days ago after putting it back on so it makes sense that its thrown this which should directly relate to the N205 if im not mistaken, good news. The fact that it hasnt thrown a P0340 seems like a good sign and perhaps rules out the cams being out of time.

I know what the mechanic is talking about down the left hand side of the engine. Now my sights arnt so focussed on this area i can hear it almost sounds like a deep deisel clack or gleg (Getting real technical now  ) coming from somewhere down there. I think its always been present and never changed so thats why ive not worried about it too much. Ive also read these engines can sound a bit diesel like so put it down to that. Its definately lounder than my GTI but it is AXX not BWA, not sure if that makes a diferance.

Going to drive as normal and see if noise/codes come back, ill see if my mechanic has and ideas where to go with the noise hes talking about.

Thanks for the help so far everyone!

[pudding]

That's some good progress 

P000A can be the N205, or it can also be one or more VVT oil rings, but most likely the N205 in your case as it wasn't even connected    If P000A does ever come back, you know what to look at next 

Deep diesel clacking could be the DMF if it's never been changed.  They tend to wobble about and generally cause a rumble in the jungle.  Again, it might be transmitting over to the left but if not that, gawd knows! There isn't a lot down that side that can make a lot of noise, other than the turbo perhaps.

[Bens313]

Yes i will keep an ear out.

It could be DMF rattle, hadnt thought of that. I think it might be a bit too predicatble and in time with the engine though. Ill let the garage have an investigate the next time im up there. Ill start a new topic for that though if it is a problem.

[Bens313]

UPDATE - Hopefully the issue is actually solved now.

I suspect when i changed the N205 i only got the coolant up to operating temp and not the oil. I took it out for just long enough to get the needle to 90 and it was quiet (My last post). A few days later we went on a longer drive in it and low and behold - clack clack clack.

Anyway i did as you suggested and got the oil control rings. I decided to fit them myself so i could inspect the parts and take my time. I did the job earlier today and the lower most ring was indeed broken. I couldn't even find the missing section, not in the housing or near the chain though. I did notice the Cam adjuster has some deep grooves much like the picture further back in this thread but wasnt in a position to do anything about it. I actually installed the housing and took it back off again to check the rings were still okay as it went on suspiciously easy and they were.

I took the car out for a long drive after and the rattle is definitely gone for now. I suspect it may come back eventually due to the grooves in the adjuster and if it does i will replace the adjuster for a new genuine one at a specialist.



Thanks for all the help.