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Re: Unusual Oil Leak

To: abcs@kc.rr.com
Subject: Re: Unusual Oil Leak
From: Bob Howard <mgbob@juno.com>
Date: Tue, 15 Apr 2003 10:02:45 -0400
Andrew,
   Let's assume that during the rebuild the dipstick did not get swapped
for another, and that the engine is not being over-filled with oil.
   A leak at the dipstick tube almost always tells you that there is
pressure inside the engine. A '74 engine should be running with negative
pressure (slight vacuum) inside the engine.  If you have a Moss
catalogue, look at its illustration of the emissions plumbing. Compare to
the equipment on your car.  
   Briefly, the carbs suck fumes from the front pushrod cover (w oil
separator). Air gets into the engine via the breather on the rocker
cover, and gets there through a hose from the charcoal separator in the
right rear corner of the engine room.   If insufficient air can't get
into the engine, the carbs can't suck the vapors out, pressure builds and
you can get leaks at gaskets and out the dipstick tube. That's how it
works on a healthy engine.
   If there is a lot of wear in the engine, there can be 'blow by', which
is pressure getting below the pistons, blowing by leaking piston rings.
This can pressurise the sump also, probably more than the carbs can suck
out.
   But look for simple and cheap things first---check the air flow
through the emissions system and see that the flow is present.
Bob


On Mon, 14 Apr 2003 22:13:29 -0500 "Andrew Sexton" <abcs@kc.rr.com>
writes:
> Hi all ... "Long time listener, First time caller"  (sorry couldn't
> resist.)
>  
> I've been a proud driver of a '74B-GT for 12 years.  
> I now have an unusual oil leak and I was wondering if anyone else 
> has
> had this problem and maybe has a remedy.
>  
> When I drive the vehicle it sprays oil out of the dip-stick tube.  I 
> can
> drive a 1/4 mile, park the car and end up with a spot on the drive 
> that
> is about 4 inches in diameter.
> If I take the dip-stick out of the tube while the engine is running, 
> oil
> spits out the tube.
> I have tried placing an 'O-ring' on the dip-stick in an attempt to
> create a seal, but to no avail.
> I drove to Victoria British today and bought an old style 'dust cap'
> that fits on the dip-stick and covers the oil tube, but to no avail. 
>  It
> still leaks.
> Has anyone encountered this issue?
>  
> The problem started after I had some work done to the vehicle:
> rebuild of the head
> new main seal
> new oil pan seal
> After this work was done, I had many leaks;  the one described 
> above,
> head gasket, valve cover, and water outlet elbow.
> (if anyone is in the area of Knoxville, TN, I can tell you where not 
> to
> take your vehicle!!..It's a long story and involves much more than
> leaks)
> I have fixed all of the leaks except for the one from the dip-stick
> tube.
>  
> Hopefully someone has an idea.
> Thanks.
>  
> Drew

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