Could it be the catch can?

S3_Mitch

Money pit owner
Hi all, I posted a thread regarding my car puffing out blue smoke recently. Today I had the turbo checked and it's not causing the issue which implies stem seals/guides/rings are the cause. However, after some research I am led to believe the catch can I recently fitted could be the issue.

I only started noticing the smoke after fitting the catch can and I really can't afford to have the head rebuilt. The cars misfiring in high rpms so I plan to replace the plugs.. I just wish I could re-fit the old breather system as a test but its all split in half :(

Has anyone heard of a catch can install causing over pressure? I seem to get 26psi of vacuum at idle and 30+psi when coasting (little high?).

Any help/advice is appreciated as always..
 

Lavis89

Well-Known Member
Regional Rep
My vacuum is off the gauge when im coasting

I used to get a bit of blue smoke if i was stuck in traffic, always disappeared with a good press of the throttle, think it was my breather filter on the catch can being clogged with oil causing a bit of pressure, put a new filter on & emptied the can (didn't have a whole lot in it really) and haven't seen any smoke since. That was a good few months ago.
 

S3 Hilife

It's an addiction
VCDS Map User
Gold Supporter
If I was you I'd re check all the breather pipework for restrictions and kinks first, some of the pipes can kink easily and check for oil in the tip but I expect the garage has already done that if they checked your turbo.

Failing that a compression and leakdown test should point out the more serious faults

Hope it turns out to be something simple

Steve
 

S3-LINCS

Registered User
I fitted a catch can to my cupra r and had smoke problems mate,

run it to the atmosphere to see if there is any change,
 

S3_Mitch

Money pit owner
Thanks for the replies.. I have it vented to atmosphere with no breather on it? It just seems strange that the problem would start now. I don't get much smoke at start-up but always if left to idle then revved or pulling away. I'm at a loss, haven't been able to enjoy the car since I got it three months ago.. money pit :(

Only thing that concerns me is the PCV removal and blocking off the manifold breather, could this cause it?
 

S3-LINCS

Registered User
remove the can and check it pal..

i have mine vented with no can as am sure a few other do on here. { looking for a bigger can }
am sure there should be no probs with manifold breather pipe blocked off as its on the how to in the stickies mate,

{ that's how i have done both the s3 and cupra r }
 

Alex C

Well-Known Member
VCDS Map User
Thanks for the replies.. I have it vented to atmosphere with no breather on it? It just seems strange that the problem would start now. I don't get much smoke at start-up but always if left to idle then revved or pulling away. I'm at a loss, haven't been able to enjoy the car since I got it three months ago.. money pit :(

Only thing that concerns me is the PCV removal and blocking off the manifold breather, could this cause it?

The PCV system is designed to suck gases out the sump and the head to avoid overpressure. I would guess that if you have ripped it all out and vented the catch can to atmos then there is no vacuum source to help draw the pressure out of the sump and head - perhaps an overpressured head isn't great for oil stem seals...

At the least I would suggest venting it back to the TIP so at least then you have a vacuum source when at full throttle as the turbo will help suck out the overpressured blow by gasses.

Another thing to note is that with the standard PCV system it will also be under vacuum at idle - so if you unscrew the oil cap you can feel the oil cap being sucked back down onto the rocker cover. Unscrew the oil cap after having ripped out the PCV system and watch it bounce around on the top of the rocker cover as all the overpressured gases rush out past it

My catch can is vented back to the TIP has only been installed less than a year. However I also have no vacuum source at idle to the catch can so my oil cap dances around on top of the rocker cover if unscrewed at idle. I am considering retrofitting the PCV valve and jet pump to give the catch can a vacuum source on idle also

Check this out: http://forums.vwvortex.com/showthread.php?6077892-How-to-install-a-catch-can-the-correct-way
 

SamHendry

Registered User
Not sure how you've fitted your catch can, but breathers should never be blocked off, will cause pressure in the crankcase/head, which could be forcing oil into places it shouldnt be going...
No you can block the inlet breather on the manifold. It's in the PCV thread in the stickies.
 

superkarl

MAN OF STEEL
26psi vacuum is insane. The units are InHg (inches of mercury) not psi
 

S3_Mitch

Money pit owner
Yeah sorry about the units, either way it bottoms out my gauge. My oil cap does dance around and there is quite a large amount of pressure coming out of the reservior. Try venting back to TIP with hockey puck?
 

S3_Mitch

Money pit owner
The PCV system is designed to suck gases out the sump and the head to avoid overpressure. I would guess that if you have ripped it all out and vented the catch can to atmos then there is no vacuum source to help draw the pressure out of the sump and head - perhaps an overpressured head isn't great for oil stem seals...

At the least I would suggest venting it back to the TIP so at least then you have a vacuum source when at full throttle as the turbo will help suck out the overpressured blow by gasses.

Another thing to note is that with the standard PCV system it will also be under vacuum at idle - so if you unscrew the oil cap you can feel the oil cap being sucked back down onto the rocker cover. Unscrew the oil cap after having ripped out the PCV system and watch it bounce around on the top of the rocker cover as all the overpressured gases rush out past it

My catch can is vented back to the TIP has only been installed less than a year. However I also have no vacuum source at idle to the catch can so my oil cap dances around on top of the rocker cover if unscrewed at idle. I am considering retrofitting the PCV valve and jet pump to give the catch can a vacuum source on idle also

Check this out: http://forums.vwvortex.com/showthread.php?6077892-How-to-install-a-catch-can-the-correct-way

Okay i'll try venting back to the TIP, not got my head around the setup in the tread you have linked but it definetly looks interesting.
 

Alex C

Well-Known Member
VCDS Map User
Yeah sorry about the units, either way it bottoms out my gauge. My oil cap does dance around and there is quite a large amount of pressure coming out of the reservior. Try venting back to TIP with hockey puck?

The hockey puck is installed on mine but I'm not sure how necessary it is if your PCV system is no longer connected to the inlet manifold; but you may as well chuck it back on (assuming it still works)
 

S3-LINCS

Registered User
i followed wellys guide on pvc delete/catch can,, I vented it back to the tip today as am looking to buy a bigger can anyways :smile:
 

S3_Mitch

Money pit owner
Tried venting to the TIP, with/without hockey puck.. no joy. The car still smokes and just noticed creamy substance on oil cap.. FML :( I'm going to get an additive put in the oil on Monday that could help block seals and fit the oe breather system. Fingers crossed because I go back to uni next weekend and it's a 350mile drive..
 

S3 Hilife

It's an addiction
VCDS Map User
Gold Supporter
Are you sure you've fully inspected all your pipework for any restrictions, I'd disconnect the lot first before messing your engine up with 'addatives' and FULLY inspect it right back to the block and cam cover outlets, Failing that as I've said above you may want to get a leakdown and compression test done. I don't think putting additives in is going to do you any favours here.

Did you use 19mm pipework?



Steve
 

Lavis89

Well-Known Member
Regional Rep
If you haven't been running the car all the way up to temp whilst chasing this issue it could explain the mayo on the oil cap. i had a bit on mine a while back but after a few good runs it's been clear.
 

S3_Mitch

Money pit owner
I have fully inspected it, yes 19mm piping.. It's a proper additive and full oil change that the garage (friend) had recommended when I enquired about the head rebuild. It's going to the garage tomorrow to get this done and I will enquire about the compression/leak down test then. I can't remember the name of the company that do the additive but it's just supposed to help block any seals that may be leaking and they want to try it before pulling the head apart (it's solved similar issues on similar cars)
 

S3_Mitch

Money pit owner
Just an update for future reference, I fitted the oe breather system which I managed to source from a helpful ASN member and got the a few different oil fortifiers put in the same day (last monday). I didn't notice a whole lot of difference after the breather change (dropped 1-2 psi of boost) and the oil fortifiers seemed to help the issue at first (less smoke). Now I have covered around 500 miles and I haven't noticed any smoke, I got a friend to rev the car at idle earlier and there was no smoke (compared to a huge puff before). So all in all the issue seems to have gone or at least is less of a concern until next summer when I have time to consider my options.
 
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