Friday, June 25, 2010

Dad’s Smoke’n Metro -

The boys gave me another nickname. Hopefully only temporarily and they don’t keep it for long. I can’t quote it as I forgot the quote exactly. It’s something like Smoke’n Jim, or Smoke’n Dad or the Dad’s Smoke’n car. The reason obviously is due to the Metro and the large cloud of smoke it has been trailing.

The smoke problem kind of gets ahead of me or behind me, oh I get so confused. For awhile it just had a cloud out the exhaust pipe at startup but recently the cloud is slightly bigger, or maybe we should say huge. Then it began smoking whenever the engine was running.

So looking under the hood I saw oil leaking high up on the engine. I removed the valve cover and cleaned the oil seal groove real well and this time used gasket cement in the groove to seat the rubber gasket into the groove. That still enables me to remove the valve cover without damage to the rather new gasket.

I also suspected the Camshaft Sensor Housing o-ring seal was leaking. It is located at the top of the engine opposite the timing belt. This area has rather easy access with 3 bolts holding the housing in place. This seal groove centered at 2.3 inches in diameter. The o-ring that was installed after some stretching is now 2.218 inches and 0.070 inches thick. I had to stretch the o-ring over a can prior to installation which if greased enough would hold in the groove long enough to assemble the housing without the o-ring moving out of place.

Knowing the o-ring groove was 2.3 inches I thought I could just order up an o-ring that would better fit the situation. Turns out o-rings are measured not in there nominal thickness but in the inside diameter (ID) and outside diameter (OD) along with the thickness. So when I went to Napa I got a little confused along with the clerk as the o-ring table he was using was in metric and it wasn’t for the nominal diameter I had brought in. Eventually I went up to Belfair Hose and Hydraulics in the business park up the street where we crunched the numbers for 15 minutes and came up with an o-ring which he had picked up that afternoon and delivered to his home that evening. He brought it to work and I picked it up that morning for $1 for two o-rings. He had both o-ring charts for metric and English. If I had the right measurements it would have been easier of coarse.

It turns out this o-ring was no too large.

So I cut 3/8 inch off and super glued it together, which apparently is an ok practice. Now instead of the 0.070 inch the new o-ring is 0.092 inches thick. Well it now lays in the groove just fine. Maybe slightly thick but it ought to seal tight as the groove will fill up with o-ring when the housing is tightened.

There appeared to be one other possible reason for the leak and that is the seam on the engine side of the o-ring seal. So I dabbed on a little gasket sealer across these two seams and after assembly I suspect the oil leak is repaired.

By the way, two auto parts stores do not list this o-ring for the Metro and the Chevrolet dealer says it is a discontinued part. I wish I would have asked what size o-ring should I order as Chevrolet uses standard o-rings I am quite sure.

I suspect the oil leaked out of this o-ring and dribbled 2 inches down the head into the corner of the exhaust manifold. The manifold shows signs of erosion at this point. With the engine running maybe the positive exhaust pressure kept the oil from burning but with the engine stopped remaining oil leaked into the exhaust system which caused a cloud of smoke out the exhaust mostly at startup. I think the leak was so bad oil eventually did make it into the exhaust manifold all the time. I never did see any smoke from the engine compartment.

I don’t drive this car enough to see the level to change on the dipstick.

The o-ring groove measures 2.209 to 2.403 inches and about 0.050 inches deep. If I need another o-ring I suspect I could order a perfect fit as there is quite a selection.

It is now September of 2010 and the Metro no longer smokes, ever!!!

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