Looking for a bit of advise

[markthenewt]

Hi.

Not posted here in ages as nowts been wrong with my A3 quattro untill now. Had it 12 years pretty much issue free.

Anyway while on holiday some thief has stolen my cats, cut them out wrecking my downpipe and other side of the exhaust.

Had to buy a brand new standard downpipe and decided to put a miltek decat on it with a 3 inch custom exhaust. Had to buy a old S3 downpipe get the flanges cut off then welded onto my new A3 downpipe so the decat would fit. Also had to buy a new Bosch lambda sensor for the decat.

Since doing this my car is smoking when idling, smells oily, grey smoke. Doesn't do it when driving only idling when sat in traffic. Didn't do this before with the standard exhaust and cat on. 185k miles on the car.

Been and had it compression tested today 200 200 195 200 was the result so all good there.

Guessing it's valve stem seals then. Don't think it's the turbo as I blew the turbo on it years ok and that smoked like mad when accelerating.

So could it be the turbo just on when idling cause of lack of back pressure now it has a decat on or do you think valve stem seals. Not using a lot of oil.

If I replace the seals then what brand is recommended?

Thanks for any help tips on this subject.

Mark

 

[markthenewt]

Pics of my readings

 

[Stuart B]

Why have removed the Catalytic Converters it won't pass an MOT..

 

[markthenewt]

Yes I know that I have 8 months MOT left on the car so I will put a standard cat back on when it comes to that time. As said someone stole my cats while on holiday and I didn't want to risk putting a new one on then it happening again so put a decat on for now to match the 3 inch exhaust system I've been waiting to put on for ages. They kinda done me a favour because it got my butt into gear to put the new exhaust on.

Is there any way of inspecting the valve stem seals with just taking the rocker cover off do you know?

 

[<tuffty/>]

Not going to see the stem seals easily at all tbh... the inlets will be next to impossible but either way you would need a bore scope or similar camera if you want to get a chance of seeing anything

In my experience the stem seals just go hard over the years... typically use elring parts.. you can get an elring top end (head) gasket set for not loads of money

Elring Standard 1.8t Headset (BAM/AMK/AUM/AGU...)

Elring Head Gasket set for 1.8t, and bores up to 82.5mm ref 461.380

badger5.co.uk

You will also need head bolts if taking the head off to sort them

<tuffty/>

 

[markthenewt]

Not going to see the stem seals easily at all tbh... the inlets will be next to impossible but either way you would need a bore scope or similar camera if you want to get a chance of seeing anything

In my experience the stem seals just go hard over the years... typically use elring parts.. you can get an elring top end (head) gasket set for not loads of money

Elring Standard 1.8t Headset (BAM/AMK/AUM/AGU...)

Elring Head Gasket set for 1.8t, and bores up to 82.5mm ref 461.380

badger5.co.uk

You will also need head bolts if taking the head off to sort them

<tuffty/>

Thanks for the reply mate,that helps a lot and thanks for the link.

Think I'm going to do the nylon rope trick to save having to take the head off as I'd rather not delve that deep if I can get away with it.

Is there any other possible cause that you know of that would cause smoking when idling?

Just don't want to have to take it apart of it could be a more simple issue to be look at first.

Has the n249 delete and all that jazz, oil catch can. Pcv simplified etc.

 

[<tuffty/>]

burning oil is generally rings, valve guide/stem seals or turbo seals

As CR is decent its most likely stem seals... turbo would typically be blue smoke under boost or white smoke if through turbine side

<tuffty/>

 

[Stuart B]

Simplifying the pcv can create positive pressure (dancing oil filler cap) this can stop the oil draining back into the sump from the turbo..


Also what is the nylon rope trick?

 

[whizz371]

You ram rope into the cylinder through the plug hole that you want to work on, with the piston just before tdc on the compression stroke. The theory is that you can then release the valve cap with pressure as you would with a valve spring compressor and the valve will not drop into the cylinder while you change the oil stem seals. I have never tried this, and I certainly not suggesting anyone does.

 

[markthenewt]

burning oil is generally rings, valve guide/stem seals or turbo seals

As CR is decent its most likely stem seals... turbo would typically be blue smoke under boost or white smoke if through turbine side

<tuffty/>

Thanks mate. I'll get the seals done, probably due a change considerering it's milage.

 

[markthenewt]

Simplifying the pcv can create positive pressure (dancing oil filler cap) this can stop the oil draining back into the sump from the turbo..


Also what is the nylon rope trick?

Had the catch can and simplified pcv running for about 8 years now and never been a problem.

The rope trick is on school way of doing it without removing the head. Put rope into the cylinder to stop the valve from falling while working on the seals. Just a bit of time saving hack really that works. People have been doing it for years. Loads of how to vids on YouTube.