Daewoo Forums and Owners Club

Hi All,

Still pluggin' on with the smokey Nubira. I have a situation now where the car runs fine, starts and stops fine and runs OK with a little bit of black smoke when it's revved hard but I tried an experiment as follows:

The car burns about a litre of oil every 150-200 miles so I pulled the plugs and found that number two is covered in oil. Not a small layer of oil but literally dripping so I ran the car 'til it warmed up, killed it an pulled number two immeadiately. No Oil. Dark tan, erring towards black but mot excessively sooty. If I put the plug in and leave it for a few hours it ends up dripping oil.

The obvious question therefore is where is this oil coming from? I had the head off a while back and didn't see any cracks but I can't see any other way for oil to gather on the plug when it isn't running. Can oil condense onto a plug as the engine cools?

Cheers,

Jools

Hi Jools,
I think the oil would be coming from around the piston rings. This could be due to general wear but as its only one cylinder, it is more likely a scratched bore or the piston on that cylinder needs new rings.
I have a Rover 216 where the plugs oil up but only over a long period (6K miles) and it is all of the plugs that are affected which indicates general engine wear.
You should do a compression test on the cylinders to verify that the affected cylinder has low compression. Then if the head is OK, you would need to inspect the cylinder bore carefully; if scratched it would need a new engine, if OK, maybe only new rings. Either way a replacement engine may be the easiest solution. Sorry for the bad news.
regards,
Ed

are you talking about oil getting on to the porcelain part of the plug if so it will be coming past the rocker gasket. if it is on the element part of the plug i would say it woul be missing like crazy

nelse

Hi All,

Sorry for the long delay but I've been working flat out for a couple of months and have been topping the oil up to get around it.

I think it is a compound problem. I found that the 5mm bore pipe that goes from the rocker box cover ti the inlet manifold had collapsed underneath out of view so when the engine was running fast, the pipe was collapsing in on itself presumably pressurising the crankcase. After replacing the pipe with a reinforced walled version the oil consumotion dropped by 50% which I'm guessing was oil being forced past the rings at high revs. The oil on the plug I suspect was a red herring caused by leakage past the rocker box seal.

It's still burning oil though and smokes when you rev it hard so it still isn't quite right. I suspect that the bore may be scratched but it seems to be a lot of work to fix.

Will post any new info when I have a solution (work permitting).

Cheers,

Jools