Lotus Elan

Oil leak (long story)

PostPost by: "David & Virgini » Thu Jul 15, 1999 11:22 pm

Last winter my Elan S2 started leaving pools of oil under the differential.
It proved to be engine oil. I traced it to a gross engine oil leak on the
right rear of the engine. I assumed the cam cover gasket or D plugs would
need replacing. The head had been "refreshed" about two years ago.

I cleaned and dried the engine with mineral spirits, simple green and air
gun. Spotless. Ran the car 5 miles. The cam cover was dry. the whole
engine was dry except the right rear engine block had oil pouring down the
side. The oil return drain tube and breather tube was dry. Where was this
oil coming from?

Had to remove air box, throttle, choke and rear Webber, starter solenoid,
oil pressure gauge line, and fuel pump. Finally with a mirror, I was able
to see a hole the size of my little finger on the underside of the head at
the rear. No picture or drawing in Elan Workshop Manual or Parts book
identified what this was. Randall Fehr referred me to p 73 in Robinshaw and
Ross for photo of underside of head. There is a core plug hole in the head
oil drain box in addition to the breather tube and drain tube. The core
plug was absent and oil, draining from the head to the oil pan was simply
running out the hole and down the block and back along the frame and
dripping off at the differential.

I was unable to easily locate the 1" dome shaped core (freeze) plug at 6
auto supply stores, NAPA ordered one for me. They have loads of cup shaped
plugs, but not dome shaped. I came upon neoprene expansion plugs that I
guess are for temporary repairs of blown out freeze plugs. This is a
neoprene cylinder with a nut and bolt with two washers arrangement to squash
the plug end to end to fill the hole. The smallest expansion plug was 3/4"
and the hole itself was 5/8 inches. I chucked it up in the drill and the
grinding wheel took it down to right size. I had to cut off the bolt and
plug because to the limited space. Pushed it in the hole, tightened up the
nut and the washer neatly filled the 1" land for the core plug. Oil tight.
All by mirror and feel.

Now I really planned to tap in the dome core plug, but had no way to do this
because of the inaccessible location. Then I removed the starter and had a
clear view of the hole. Could and should have done the whole job this way
and left the carb and solenoid in place. With a 16" drift and 6" swinging
space under the jacked up car, I could have replaced the core plug properly.
By the time the back ordered plug arrived, the car was running again without
oil leak.

I'm quite pleased with myself, no one, I assure you can see the non-original
part. When I overhaul the block in a year or two, I will effect a proper

David Caley, Indianola, Washington (the other Washington)

"David & Virgini

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