THE PORTAL HUB - Pinzgauers, Haflingers, Volvo 303s and more!

Yes, I remember using Hi-Tack in my past Early Bronco work just to keep the gasket in position. But that means next time you replace the gaskets it's more work to get the old one off and clean up the surface for the new one!

Did you ever nail down the source of that leak ?

Perpetual leak hunter -- Ron

rmel wrote:Did you ever nail down the source of that leak ?

Perpetual leak hunter -- Ron

Haven't tried yet, waiting for warmer weather and a time when my Brother can help. I need to replace the exhaust headers and install the SAV flex kit also and it makes sense to do that at the same time in case we have to pull the head. I have quite a few parts on hand from SAV in anticipation of doing both.

Interesting that I just looked at it and it's still leaking but not as bad. Not running down the exhaust header like before (unless the rain and snow washed that off!). I see oil on the outside of the oil return tube also. Only a couple of things have changed since it was leaking worse:

One thing is that I changed the oil using Dino 30W and I believe it had Mobil 1 in it before, and I put in the correct Mann oil filter. The old oil had a fuel smell and was about an inch over the high mark. Dark oil but with clear liquid around it when I poured it out of the drain bucket. So I think it had quite a bit of gas/condensation in it. Had a little bit of froth in the oil filler tube, but not much.

The other thing is that we drove it on a 120 mile round trip and spent a long day 4 wheeling with it last week. It hasn't seen much use for a few years.

I will post what we find out.

Got it, and will be very interested to know the results. A quick and dirty
would be to do a compression test on all 4 and compare.

Oh, touching the heads is no easy feat. There is no head gasket.
The head and cylinder need to be matched by lapping them together.
Putting all that back together involves a lot of experience with this
particular engine, can be a huge PITA.

We got the exhaust manifolds off yesterday in preparation of putting on new used manifolds and the SAV flex kit. So I was able to get some better pictures. The original stud that was leaking even when the engine was not running seems original, no helicoil on it or any of the others. The nuts on Cylinder 4 that includes the leaking stud came off much easier than the others. The exhaust manifold on it had been modified by a previous Owner to be all hard pipe with no flex. My best guess right now is that the leak is coming from the oil drain tube above that shows oil on it, and getting into the #4 exhaust manifold gasket that wasn't tight. At least that's a hope.

And while I was down there I noticed another oil leak on the Cylinder #2 fins.

Any thoughts?

With respect to the leak associated with the exhaust stud, hard for me to be
too conclusive here, but it does look like there is a bit of oil weeping at the
Head side of the oil return tube. There is an O-ring at that end, in fact the
only O-ring for all tubes. However, you did mention that you see oil dripping
even when the engine is off, but is that just after you turn the engine off? Soon
after does the oil leak stop? If it does that points to the O-ring, as a running
engine the oil fills up to some degree under the valve cover so after you turn the
engine off it would continue to leak for a bit until fully drained. If you can confirm
the leak is at the top of the tube it is actually possible to replace the O-ring
without removing the head -- I have successfully done this myself. Oil leaks can
be trick to find, sneaky paths as capillary action and surface tension can make a
leak appear to be one place and it's not. One thing you could try after you put the
exaust back together again is stuff a bit of a rag around the top end of the oil RTN
tube and if the leak stops you have it nailed. If that's your leak I can talk you
through the procedure, a trick from Jim L.

Your other leak, showing up on the cooling fins of the jug. Is likely from the topside.
Either push-rod housing or tube gaskets. These cannot be replaced without removing
the jugs -- and that is something you want to avoid unless your hemorrhaging oil or
need a ring job. You could inspect for that by removing the top tin closest to the fan.
Inspect the push-rod housings and gaskets for leaks. If it's one of the grommet/gaskets
you may be able to band-aid that with some high temp RTV. Cy #1 and #2 are easier
to get to than #3 and #4, for those more tin needs to come off. A good endoscope
will help the inspection process a lot, esp. for the back 2 cylinders.

The picture is a little deceiving maybe because of the flash. The oil around and along the oil return tube is very obvious in real life.

The exhaust stud leak seems to continue indefinitely after shutting down. When I was checking it more often, it could be a day or days and i'd still see a bubble on the stud after having wiped it off.

Luckily it rarely drips to the ground. It drips along the bottom of the center chassis tube that shows it in an increasing fashion over time.

Well one explanation is that a leak from the oil return tube getting to
the exhaust port will "well" up oil between the head port to the exhaust
flange as there is a compression gasket in there leaving a bit of a gap.
More oil than one would think can collect there -- I have seen this
myself on my rig.

If you are sure the leak is from the top of the return tube, then it
would be easier to attempt a O-ring replacement with the Headers
off as the best approach for success is to remove the bottom tin
and clean the oil return tube thoroughly around the spring end near
the block -- getting any build up off of it. It now is obvious the
procedure is to push the return tube into the block from the head side
compressing the spring so you can clear the old O-ring out and replace
with a new one. So having a relatively clean tube at the spring end is
good to minimize potential damage done to the washer/gasket on the
block side. But you really want to be absolutely sure this is where the
leak is as you can see this is a wee bit of a tricky procedure and has a
little risk touching the tube.

One other band-aid approach would be to RTV on the inside by removing
the valve cover and applying RTV at the mouth of the return tube. There
is very little lip there to bond to however. You would have to be very careful
not to close off the opening but have enough RTV to form a seal. This may
hold for a seasons worth of trucking and then make it a more permanent fix
as a winter project.

I just realized I left a cliff hanger here and didn't detail the steps to replace the O-ring

First you need a tool to push the return tube into the Head. A 5/16" x 4" fully threaded bolt will do.

Round the bolt head so that it just fits inside the tube but leaving a 1MM to 1.5MM shoulder on the
head and about 1MM larger in diameter than the I.D. of the tube. This then "catches" on the rim of
the tube. This is the pusher tool.

With the valve cover off, find a place on the wheel well side as an anchor point for a deep socket.
Place a New lubricated O-ring on the bolt, with a nut and washer threaded on the shaft. Place the
pusher on the return tube, and the other end inserted into the deep socket. Use the nut as a driver so
that you can push open the return tube exposing the O-ring seat in the head (and it's helpful to clean
and lube the opposite spring end of the return tube but the bottom tin needs to drop for that). You
should see an Orange silicon O-ring. Pluck it out with a dental pick, clean the seat make sure there is
no material stuck to it -- use 10W40. Now swap the old O-ring with the new. Re-seating the new O-ring
takes a lot of patience. Crank the tube closed slowly, check underneath as you go to make sure the
O-ring did not roll off it's seat. You can see bright Orange clearly from under if it rolled -- this in fact
was my problem, see PIX below.

After the bolt has no more pressure on it, if the tube did not fully seat you may need to rotate it slightly
using a pair of narrow pliers -- caution here, easy will do it, should "pop" in place if it was hung. Check the
seating again making sure the O-ring didn't roll off it's seat.

Also a key point, if you want the right O-ring, buy it from EI -- Orange Silicone !!

First fire up after the exhaust manifold, gasket and flex kit installation today. All exhaust flanges and studs are clean, but there appears to be oil or gas leaking either on to our out of the same #4 flange and then it runs down the flange and onto the same stud that appeared to be leaking oil before this re-build. It looks more like gasoline than oil, but I did just change to fresh oil yesterday. I cleaned off the adjacent oil return tube as much as I could and I couldn't see any visible oil leak coming from it during the short time I ran the engine.

https://www.youtube.com/watch?v=PRnBFy7 ... e=youtu.be

Minor oil leaks can be very hard to track down. If you look back at the PIX I posted
that leak took me over a month to find. It may look very obvious in that PIX but looking
up at that very same spot with the naked eye I could not see any oil. that PIX was
taken with a high intensity LED endoscope. When I put the scope in that general area
then the leak was highlighted as seen -- Bingo! You have no idea how happy I was to nail it.

When a leak is very minor the oil tends to adhere to a surface (even upside down, but not uphill))
due to surface tension, in my case there were no visible drops seen coming off the tube, the
oil followed the fin to the exhaust flange, went around the flange then welled up and dripped of the
bolt -- two stink'n drops/minute constant. So unless you put some tracer die in the oil and use a UV
light, or a very high intensity LED and scope you my not "see" the source of that leak -- assuming it's
oil and not gas, but the latter you should small that esp. near the exhaust due to rapid atomization.

One thing to try is stuff a small rag in the fins right at the head and 1'st fin around the tube and see if
that stops the leak beyond the time you typically see it develop. Don't forget to take that combustible
material out though

Started the Pinz again yesterday and tried the rag stuffed around the oil return tube. The stains in the pictures are from the day before, before I started it up with the rag in place. I didn't see anything visibly flowing with the rag around the return tube, like I saw the day before with no rag. Sure appears that I have the same oil leak that rmel had, maybe more.

One step closer to nailing that then

In your case it would be a failed O-ring that is just giving up the ghost.

One other thing to try that is less invasive than attempting an O-ring
replacement, is good'ol RTV -- as a temporary measure and to verify.
Just remove the valve cover, clean thoroughly around the Oil return tube
with brake cleaner so there is a good bonding surface. The return tube
extends slightly above the head surface to give a slight lip to add a bit
of RTV arounf the O.D. of the tube, that should seal that leak.

I would not guarantee this will hold for long with heat/expansion but it
should hold long enough to indite that O-ring as bad. Might hold up for
the season if your lucky

clean thoroughly around the Oil return tube with brake cleaner

Just be sure to prevent the brake cleaner from draining into the engine oil!