oil leak

You didn't mention the year of your vehicle...  the following applies to 93-
98 Altimas.

I had a leak on my 93 Altima after a 3500km roadtrip in the heat of the
summer.  After searching google, there were 2 possible culprits.  

#1 was the crank seal.  

#2 was an o-ring between the timing cover and the engine block.  here is a
good website showing how to do the repair, and why it failed.
http://www.prb2.com/altima/   (also has a good write up on the timing chain
guide issue on these motors)

My problem was the crank seal.  It took about 30 minutes to replace.  I still
have the O-Ring I got from the dealer.  Since my car no longer leaks, I
haven't bothered to do the job.

t

Bill wrote:

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failed.http://www.prb2.com/altima/  (also has a good write up on the timing chain

Well, it's Thursday night and I just took another look.  When I was
under the car and watched the drip form I had then gone over to an old
block I have here and thought I identified the leak as somewhere near
the embossed "Z" on the block inside the lower timing chain cover near
the oil port into the block.  Then when I went in to fix it, moving
the power steering pump toward the engine wall, I thought, and maybe
did, identify oil on the bottom of the PCV breather.  That off and on
twice the last 2 weekends didn't fix it.  Tonight I was looking at the
Haynes manual and the photo of the timing chain cover on page 2A-17
and seeing how the breather access is stepped out, that when I mashed
some RTV between the block and the breather edge I might not have
gotten to a potential leak.  Getting under there tonight I didn't
clearly see oil under the breather and in fact really didn't clearly
see oil there that second time I removed the breather because the
earlier RTV application was a bit messy and it is a shiny black.
Under there tonight I realized that somewhere I had lost sight of the
probable leak being just about where that embossed Z is.  If one looks
at photo 12.3b on page 2A-15, the oil first appears as a drop on the
bottom of the outcropping just beyond the back end of the far left
arrow.  It's related to the oil pump.   One can't get a good look at
that spot not because it isn't possible but because the power steering
pulley is in the way.  If the mechanic had overtorqued the bolt above
the port of the oil pump he may have cracked the timing cover a bit.
The last 2 weekends I was concentrating on the PVC and breather.
Apparently I should have put on my reading glasses and taken a close
look at the timing cover while the power steering pump was held to the
firewall with a wire clothes hanger.  Well, if the weather is nice
that will get done this weekend.

Bill

Well, I was under there today.  Turns out it probably isn't damage
from the local garage prying the engine over as I don't see any clear
damage to either timing chain cover.  First thing I did was to run the
car and watched closely near the oil pump area of the timing chain
cover.  Oil did appear but its source wasn't clear.  Also, there was a
bit of oil on timing cover bolt near the water pump.  Shutting down
the engine, I unbolted the power steering and wired it to the
firewall.  I removed the metal brace that looks like a British Pound
symbol near the head and the engine mount.  Nothing appeared to have
been leaking there.  I inspected the PCV breather enclosure closely
and noticed there was a bolt missing.  It threads outward and holds
the breather together.  Somehow when I changed breathers I hadn't
noticed that was missing.  Fortunately I could get the bolt from the
old breather into it without removing the breather.  That snugged up I
was pretty sure that had been the latest leak as it sits directly over
the plugged access to the oil pump in the timing chain cover where the
drops of oil had been appearing first.  So, back went the power
steering and the alternator snug and I started it back up, waited a
minute, and there was soon oil accumulating that sealed hole to the
oil pump in the timing cover and soon dripping from the bottom of the
CVJ under the power steering brace as well.  I go in again, unbolt the
power steering pump, wire it to the fire wall, and take a number of
paper towels.  I tucked one in between the PCV valve breather
enclosure and the block, taped one under the breather with duct tape.
taped one over the timing cover sealed access to the oil pump and this
paper towel also covered the small bolts above and below the oil pump
sealed access.  Ran the engine and one or a couple of those paper
towels were effectively interdicting the oil drip.  Shut down the
engine, unbolted the power steering pump, and first checked the paper
towel between the breather and block, no oil, checked the paper towel
taped to the bottom of the breather, no oil, checked the paper towel
taped over the plugged oil pump access and yes, oil in three spots,
from the top bolt from around the sealed hole and from the bottom
bolt.  I suspect that the mechanic didn't seal those two bolts
properly nor the bolt near the water pump.  Oil seems to well up
around the threads and through the slit in the lock washer.  Like he
put a thin bead of RTV outside the bolts but not on the inside of the
bolts.  I checked the old block I have here and those are blind bolt
holes.  So, after it dried from cleaning, I got a good bit of RTV into
those holes and around the base of those bolts and tightened it up.
Also covered the tin plug in that access hole.  Now it's drying and
hoping for the best tomorrow.

Leak still there.  It seems to be RPM/duration dependent.  A seven
mile trip to the post office this morning, parking in a fairly clean
spot, left a softball sized oil spill in the time it takes to check
one's mail.  So, I'm thinking it's seeing the oil pressure and
therefore probably right near that oil pump output port leading to the
oil filter.  The PCV breather separator would see oil but not under
pressure.  The oil filter aluminum stand seemed fine and a paper towel
under it didn't accumulate oil when the towels were around the
breather and timing cover.  I have changed the oil pressure sensor,
that more than a month ago.  Wish I could run the engine without the
power steering pump in place but without the water pump that would
seem foolish.

It could be a cracked block that I just don't see.  When it went into
the transmission shop for a leak at the differential, first they
changed the oil seals but that didn't help.  That tranny leak had been
there since before the engine swap out a year ago and those guys said
they replaced the seals.  When the transmission place changed the
seals again and it still leaked the mechanic showed me how the
passenger axle seemed to be into the differential at a slight angle
and that was probably causing the leak.  We left it at that until a
month or two later I asked it they could put on a rebuilt head and
they said yes to that and fixing the transmission leak.  I had gotten
promised multiple time by them that I would get it back without
leaks.  Afterwards they denied that agreement and claim the oil leak
must be caused by something broken before they took the engine out and
it's not their responsibility.  Anyway, once the engine was out a
thought was that the mounting bracket for the CVJ was bent although
not noticable to the eye.  The engine that had been taken out the
previous year had some years before seen a bad front accident.  A
thought was that the same CVJ brace had gone onto the replacement
engine at that time when it at least got a short block and again last
year with the used engine and was presently still causing the leak.  I
had a brace with the parts from the engine replaced last year and
noticed there is a placement tit on the brace.  I suggested that tit
might not have been in place and a side of the CVJ mounting bracket
might not have been sitting flat.  No answer on that but I did give
them the other brace to put in as well as a new axle while the engine
and transaxle was out.  There's no leak from the transaxle now.  That
brace is a hefty piece of steel but this is another block.

Unless the engine put in last October had been in a bad front end as
well there isn't any reasonable way this block can have a crack at the
power steering or CVJ brackets.  Besides if it were a crack at the CVJ
mounting bracket bolt holes the oil wouldn't be falling from the
inside power steering bolt (with the support pipe) onto the CVJ when
the engine is run with no paper towels and the wheels not moving and
the CVJ not slinging the oil.

I think I'll go another week sliding a piece of cardboard under the
car at work and take it when I leave and next Saturday do the paper
towel test again but this time after putting it back together taking
it out on the road where oil pressure will be up there.  Also, the
stresses of a drive might have an effect on the leak.

Bill
Heard County, Georgia, deep in the Southland, a few short miles from
the setting of the book/movie I WAS A PRISONER ON A GEORGIA CHAIN GANG

(Had the title wrong.)

Well I say you should check the o-ring between the timing cover and the
engine block.  

Here is a good website showing how to do the repair, and why it failed.

http://www.prb2.com/altima/  

(also has a good write up on the timing chain guide issue on these motors)

Bill wrote:

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Is there a charge for this website?

The mechanic charged for a new lower gasket kit which covered the
timing covers and associated seals and gaskets.  The seal you display
is I think the seal internal of the timing chain cover and not
accessible.  Great suggestion except one would need remove the lower
timing chain cover to access this.  I see what appears to possibly be
this displayed seal pressed into the engine block between the two
blind threaded bolt holes at that sealed oil pump access port.

Bill

no charge for the website... looks like some guy just decided to post the
repair procedure.  I found it on Google.  Its also neat that he showed the
difference between the old style and the newer beefed up style grommets.

From the description, you do need to remove the lower cover.  When I did my
crank seal, we had that part of the engine stripped down in less than 30
minutes.  Once you remove all of that stuff, its easy to work in there.

When I have pesky issues like your oil leak, I always google for other people
who have had the same problem as it is very probable that the problem is
common.

t

Bill wrote:

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So, that's 30 minutes to remove the lower timing cover with the engine
in or out of the car?

Bill

In the car.  I have a 93 altima 2.4L.

Remove valve cover
Remove alternator
Remove engine brackets
Remove upper timing cover
Loosen A/C Belt
Remove crank pulley bolt
Remove crank pulley
Remove lower timing cover

t

Bill wrote:

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Very odd.  I distinctly recall previously looking at the base of the
oil filter pedestal and seeing the edge of a Felpro-like gasket.  This
morning I decided to change out the pedestal though I was sure the oil
was migrating from elsewhere.  First thing that registered was that
the more difficult to reach of the four bolts, though not _that_
difficult to get a wrench on, wasn't very tight.  I get all four bolts
out, remove the pedestal, and look for the gasket.  Couldn't find it.
Still can't.  It's possible it's in there someplace but I've no luck
finding it.  The surface of the pedestal looks very good as if it
could have made an almost oil tight seal.  When I had returned to the
AAMCO in Newnan, GA, about the oil leak after their work, the manager
or possibly owner, had the car put up on the lift and said since there
was oil all over that the pedestal was cracked and the oil sensor also
leaked and it wasn't his responsibility.  Well, RTV is drying and no
test until tomorrow.

By the way, did I see somewhere that if the top timing chain cover is
removed one needs to buy a head gasket set for the upper seal?  And I
wonder about that idler pulley.  I see it's brace is held on by three
bolts, that from looking at a spare brace I have here, but getting to
two of those three bolts looks like it's almost easier to lift out the
engine for access.

Bill

I havent had to remove the engine in my 93 altima for any reason.  If I did,
it would be to replace it.

hope you are successful with the oil pedestal.  honestly if I were you I
would have set the car on fire already.... :)  not enough patience.... haha

t

Bill wrote:

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Sunday afternoon after a round trip to town, it still leaks oil.  So,
regardless if the mechanic left out the pedestal gasket the leak is
from elsewhere.