<VV> Changing the oil pressure switch on a turbo engine

Jim Simpson simpson661 at gmail.com
Thu Mar 28 12:39:18 EDT 2019

Bryan Blackwell and David Malcolm pointed out what looks like the solution
-- the MAC SC40 socket.

  I'd checked in the shop manual under Engine Mechanical Special Tools and
didn't find anything there for the oil pressure switch.  But I hadn't
thought of looking under the Electrical Special Tools -- sure enough, GM
showed the Kent Moore J-21757 socket.  It has a relatively short, fat
section to fit the oil pressure switch with a narrow top that should clear
the various fuel and oil lines on the turbo engine.

Some versions of the MAC SC40 look like an exact match of that socket.  But
if you go out and look for one, be aware that not all MAC SC40 sockets are
the same!  Most of the ones I found on-line look like a more modern version
-- tall and fat, similar to the socket that I already hand that wouldn't
clear the lines.  Look for a 3/8" drive version with a flaired end and
narrow drive end.  (Check the shop manual under Electrical Special Tools to
find an illustration.)

I found one in ebay and ordered it.  I'll find out in a couple days if
Bryan, David and I am right.

(The K-M J-21757 is also out there, but costs anywhere from 4x to 7x as

Jim Simpson
Group Corvair

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