Help Diganosing Oil Burn & Smoking Mazda 2.0L

[CU55TM Disco]

Gday Folks,

Recently I purchased a little Mazda Premacy Mini Mini Van for the Mrs to keep the Kays off our D2.

Its got 150 odd kays on it, and its 2003 Mod. It runs the 2.0L Mazda FS engine that was also in the SP20 323 astina, and in the last of the 626's.

Purchased the car about 3 weeks ago from syd, and on the way home, the wife noticed that it was blowing a little smoke whilst navigating through the burbs, I put it down to just being a city car, and needing a good solid drive to clear its throat.

Anyway, she drove it for around a week, and I then have it an oil change + filter just so I knew where it was upto. Used Nulon 15w40 Semi Syn as recomended by the Nulon App.

Following this, it did a trip to Nelsons bay, and a trip back to the parentals on the weekend just gone, I noticed it used a bit of oil on the trip, and had dropped to around half full on the dipstick.

Topped it back up before heading home, and checked the PCV valve to make sure it wasnt blocked, and the cause of its using oil.

As we were just about to leave, the car was idling in the driveway and started to produce MASSIVE amounts of smoke, the more U revved it, the more smoke it produced, it would not clear...

Anyway since then, its had 2 more subsequent oil changes (oil only) and has done the return trip from tamworth to newcastle (260 odd kays)


What I am trying to determine is, is it Oil rings or Valve Stem Seals?!?



I have had the valve cover off, and checked for sludging, thinking that the oil might not be able to return to the sump and is pooling in the valve train. All looks fine.



There doesnt seem to be excessive blowby comming from the PCV valve at idle.
It seems only to blow smoke when cold, and left to idle. If you start it cold, and drive it straight away, it doesnt seem to smoke up.
Once warm, there is minimal to no traces of smoke.
I have added a bottle of Nulon "Worn engine treatment" with the first oil change, and half a bottle of nulon "stop smoke" with the last. Neither seem to have much effect.
Plugs 2 and 3 had evidence of oil around the base of the plug, and were oily on the threads, and very gunked up on the electrode.
I have resealed the valve cover gasket around the plug tubes thiking that it might be getting in there.





So, where to from here???


Is there any tests I can perform to determine definitivly one way or the other WHERE the oil is getting in?


Do I whip out the Valve stem seals, and replace them, or strip it down and do a ring-job on her???



This was suppose to be a cheap/economical runabout so I could focus some time on the disco, not another project car...:mad:

[bsperka]

Have you done compression tests(dry and wet?). They may point you in the right direction.

[Blknight.aus]

wrong oil or the engine, and sticking rings would be my guess.

[CU55TM Disco]

Have you done compression tests(dry and wet?). They may point you in the right direction.

I have not, general running and driving of the car would indicate that compression (read: performance) is good. :D

wrong oil or the engine, and sticking rings would be my guess.

nulon recomend 10w/40 or 15w/40 as an alternative, i was under the assumption that the 10w40 would be more liable to burning due to its thinner viscosity, hence i went with the 15/40.

[Leigh 110]

smoke from long idle points to valve stem seals,
First thing-carry out a comp test, wet & dry

[CU55TM Disco]

Okie Doke, Carried out DRY compression test, all cylinders are 900KPA.
Spec is Min 824KPa, Standard 1177KPa, with max differential of 196KPa between cylinders. Did not perform wet Comp Test as dry results seem good enough.

Pulled all plugs and dropped inspection camera down the plug hole, all pistons seems to have a normalish looking buildup of carbon ontop, #2 is very wet with oil...

@ idle there is the slightest wisp/hint of smoke at the tailpipe, if u hold the engine at a constant revs, say 3000rpm, i get clouds and clouds of smoke out the back, however, i have found that if the car is driven, then no smoke, as though the slighest little bit of engine load clears it up...

Rings????

Stem Seals????

When hot it doesnt seem to blow any visable smoke, but it did use a bit of oil on a recent trip from newcastle to tamworth...

[bee utey]

One oily cylinder suggests a dislodged stem seal on that cylinder's inlet valve guide. Time to pull off the cam cover and have a look?

[CU55TM Disco]

One oily cylinder suggests a dislodged stem seal on that cylinder's inlet valve guide. Time to pull off the cam cover and have a look?


I have had the cam cover off previously, as I suspected that oil may have been getting into the cylinders via the Plug Tubes, i had a bit of a poke around in there hoping to find a gallery that had carboned up or similar and may have been flooding the top end with oil.
Nothing looked awry when I was in there, but U cant see much of the valve anyway with all the other guff in the way.

Is it possible that the engine may have had a Re-Ring at some stage, and the oil ring on Pos2 has been installed incorrectly???
There doesnt appear to be any evidence of the engine being apart at any stage during its life. The cam cover has been off prior to me being in there as there is sealant around the edges, Im hoping that it was off to do Cam Belt, as it was due at 100K.

From all the googling I have done in relation to this engine using oil, re-ringing and Valve stem seals seems to be the major work that people are doing to them, albeit, all the posts on forums I could find related to vehicles stateside...

[POD]

One good tell-tale for valve stem seals is that the smoke will be worst after slowing down through the gears; the higher manifold vacuum (lower manifold pressure) sucks the oil in past the valve stems, then blows it out as blue smoke as you accelerate again. A typical example is seeing a plume of smoke behind you as you take off from traffic lights.