Last May (2001) I acquire a 31K 92 one owner coupe. Because I drive the
car exceedingly hard, and because I was not smart enough to ask the list’s
opinion, I changed the Castrol 20-50 to Castrol Syntec 5-50. Now, 20K
trouble free miles later the cambox seals are leaking a significant amount
of oil,(it is standing in a small puddle on the top rear of the V,
undoubtly because the seals have shrunk.
Q: Will changing back to Castrol 20-50 re-expand the seals?
Jim Fox
XJS 92 Coupe
XJR 99 “Fordor”
PS: The XJS has been retired as a daily driver and replaced with a 99 XJR
sedan with 40K. It is a rocket but not as much fun to drive as the coupe,
and like Kirby says, you get cheated out of 4 cylinders. All true, but the
supercharger does offer some consolation.
I changed the Castrol 20-50 to Castrol Syntec 5-50. Now,
Why 5w-50 ? should be 15w-50 0r 20w -50 for summer driving.
20K
trouble free miles later the cambox seals are leaking a significant amount
of oil,(it is standing in a small puddle on the top rear of the V
You see oil running down the OUTSIDE of the cam covers onto the exhaust heat
shield ? Perhaps you mean the tappet block is leaking at the head / tappet
block joint ?
Q: Will changing back to Castrol 20-50 re-expand the seals?
Try 15w-50 or 20w-50 , also look around after cleaning up the oil to see if
you can locate the exact spot that is leaking. The rear of the Vee has other
palces that leak like the sender units, their banjo fitting. The oil sits in a
pool on the outer edge of the tappet blocks, I don’t see that the oil level
would be high enough to flood the inner valve cover tappet block joint
although it WILL do that on the oputer joint.