Jump to content

sdi puff of blue smoke at cold start


mk2
 Share

Recommended Posts

I been having an increasingly curious scenario over the last few months with my black Sdi.

When it's cooled down overnight after a decent run the previous day (fully heated up engine), the next morning when i start it stone cold, for the first two seconds there's a puff of blue smoke and some misfiring. It doesn't do it when hot. There's no smoke ever. It's always done it, but it has definitely been getting worse.

When the engine is properly warmed up, you can occasionally hear a ticking/pinking sound. I originally thought that it was injector or valve train related, now eliminated. They're ok me thinks.

If i let it idle for ages (hot) then cane it (in idle), there's still no blue smoke. So probably not worn valve guides, which was one of my first thoughts.

Could it be a dodgy piston ring - oil control variant...? Or maybe no honing left on the bores?

Compression is fine. Doesn't use any oil really. Maybe 1L in 15,000miles.

My guess is something to do with the rings or bore scoring. I've never had the head off so no idea of condition of internals. The cam lobes and valve train look clean and unmarked (with rocker cover off). I don't think it's ever had a valve contact with pistons situation.

I only notice it as my silver Sdi never ever does it.

Thoughts?

 

Edited by mk2
Link to comment
Share on other sites

15 hours ago, Rich said:

thermal expansion of piston rings.

yeah, i was thinking along same lines. so basically the engine must have been caned when new and the rings probably need replacing. i'll leave it until it goes bang then. i wonder if i'll get some cool blow by scoring on the pistons over the next year. i have a spare lump ready to swap. By the way, i still owe you a fully restored mint mk2 rallye in return for a little LED lock button bezel... :)

@Sausage yeah definitely oil smell (blue smoke)

@lupo 1.7sdi timing is perfect (new injection pump and injectors- triple checked!)

Link to comment
Share on other sites

one lupo (2 new boots- so common they always split on the half shaft), one polo both outers completely toast- no idea how it passed mot (spider disintegrating on one side!), one mk5 both new outers. 3 happy customers!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.