Mazda 626 (1997 - 1999) - 1999 2.0 blue smoke on start up

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Thu 16 Oct 2008 13:50
1999 2.0 blue smoke on start up - HLyon
Everything I've read on the internet suggests that the valve stem seals are leaking.

Spoke to someone recently that reckoned it was normal for 2ltr cars to do this as the automatic choke was 'forcing everything thru'. Reckoned it could be fixed by giving it a tune up.

I would have thought that if a car had an ECU then it wouldn't have a choke or be tunable, other than by remapping the ECU. Which would be a modification rather than maintenance.

Edited by Webmaster on 11/05/2009 at 18:45

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Thu 16 Oct 2008 19:57
1999 2ltr Blue smoke on Start up - Hamsafar
The person you spoke to was talking a complete load of baloney!
What you read on the internet about the valve seals sounds more like it.
It sounds as though oil is seeping into the combustion chambers during the night. It's not a serious problem, not worth doing much about other than trying another make of oil which may not seep as much or be as smokey, but don't be tempted by a thicker grade oil as these engines like a lighter oil for as the hydraulic tappets can clatter on startup with anything higher than a 5w40.
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Thu 16 Oct 2008 22:33
1999 2ltr Blue smoke on Start up - DP
It'll probably soldier on for years like this. Just keep an eye on the oil level and don't worry too much about it. It's one of those jobs where the parts cost peanuts (literally pennies per seal), but the labour doesn't.
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Fri 17 Oct 2008 10:20
1999 2ltr Blue smoke on Start up - HLyon
As I thought then, cheers very much.
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Fri 17 Oct 2008 10:28
1999 2ltr Blue smoke on Start up - RichardW
Trouble is that the burnt oil may well gum the cat up, and it may stop working leading to an MOT fail; or it may fail on HC anyway - the limit is quite tight for modern cars. Failed valve stem seals usually give themselves away as oil smoke at start up, and oil smoke on overrun from higher engine speeds (high vacuum sucks the oil in past the seals). It might be possible to change the seals with the head in situ, but it may well need to come off to be able to compress the springs - depends on how the cam / carrier / headbolts are configured.
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Fri 17 Oct 2008 13:34
1999 2ltr Blue smoke on Start up - HLyon
Don't see any in the rear view on overrun, only in the morning.

I discovered recently that I've been overfilling the oil for the best part of a year (as described in a different thread), so I suspect that hasn't helped any.
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Mon 11 May 2009 17:08
1999 2ltr Blue smoke on Start up - HLyon
I'm looking for some help on oil choice. The manual says 5w-30 or 10w-30.

Bearing in mind the above, should I be using mineral oil or fully synth?

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