Several years ago, I rebuilt my 1.6 litre TD motor, putting
in 20 thou oversize pistons, and fitting them with Hastings oil
and compression rings - all chromium.

        I ran conventional oil for several thousand miles, then
switched to Delvac 1, the Mobil synthetic designed for diesels.
I slowly began using oil, at first a litre every thousand miles.
Then  several months ago, down to two hundred miles to the
litre.  At that point, I went back to Delvac conventional oil, as I
could not afford the $ to keep feeding the motor, synthetic oil.

        On my holidays just completed, the consumption increased
to about 50 miles to the litre. Needless to say,  when checking
the oil, it has the cleanest oil for a diesel!  The exhaust is sky
blue and never black.

        Back home, I just completed a compression test, thinking
the rings must be worn or broken for some reason. The
compression values average 480 psi throughout, which is
what they were three years ago.

        My question is then, can the compression rings be good,
but the oil scraper ring fouled or broken?  Alternatively, can
the valve stem seals be so leaky as to allow oil to leak into the
combusion chamber?

        The motor has never ran low on coolant, or over heated. I
changed the turbocharger, thinking the impeller was drawing
oil from the oil lubricated bearings and driving it into the motor.
Oil consumption was unchanged.

        I'm baffled, annoyed and disgusted.  What is the percentage
likelihood of leaky valve stem seals versus  defective oil scraper
rings? ? ?  Any other possibilities not heretofore considered? ?

        E-mail me directly if you have a clue, as the head is coming
off today at 1100 hours.

  Gary A Meek
  Sherwood Park, Alberta
  Canada

  82 Vanagon,  turbo-diesel
  83 Quantum,  turbo-diesel
  83 Audi,  turbo-diesel