Background:
Way back in May I drove out to Phoenix and on the way had a MASSIVE (6
quarts 200 miles) oil leak that ONLY occured during sustained highway
driving. Since then I've only really had a chance to poke around and try
and see where it was coming from. It appeared to be coming from the IP
where it connects to the engine, but I was driving all over the place and
was busy when I wasn't driving so I just kept it under the magic speed of
75 (only 1 quart per 1000 miles) and drove away. Some rear suspension
issues came up that made the car almost undriveable, and while it was down
for that I also knocked out what I thought was the cause of the oil leak.
Symptoms:
Sustained highway speeds, can not duplicate by revving engine,
driving around town in S, etc. Only occurs during high load.
(Presumably crankcase pressure is causing leak to occur and that follows
load)
MASSIVE leak -- entire bottom of car dripping, back of car wet, etc
No discernable source -- its in an awkward enough position that it is not
very obvious where the leak is coming from. Does not help that oil cooler
lines run right underneath IP.
Solution (So far...):
When I removed the IP there did not appear to be any gasket material.
Turned out that there was a gasket, it just looked JUST like the metal and
was almost the same thickness as the surrounding metal. That gasket was
so far gone there was essentially no gasket. There was also lots of oil
residue below and on the sides of the IP, but nothing above it.
Scrubbed off the old gasket and installed a new one, which upon the 15
miles or so I've driven so far (some at *high* sustained speeds) seems to
have fixed the leak. Normally it would seep constantly, which has not
occurred yet, and nothing leaked after the high speed excursions. After I
drive to Starkville this weekend should be able to post a definite answer
about it being the cause of the problem.
Thanks to everyone that helped me out in May and offered help while I was
away from home!!
John
'79 300SD
