aquajake

Hey guys, long time lurker, first time poster. I've been battling an oil leak an '86 4runner, and I'm at the end of my rope. I installed a used engine a few months ago, and ever since I've been dealing with this leak.
I started out by checking the valve cover, and replacing the seal and half moons. No change. Next, I checked the front main, since that appears to be the most common issue. (I got a 94 crankshaft seal, in order to avoid the groove problem) I also replaced the oil pump seal at this time. I also checked the distributor O-ring just to be sure. This didn't make any difference. Then I redid the two half-moon gaskets, hoping that I had somehow messed up the gasket, or not gotten enough gasket material on em.
No change, the leak continued to worsen over the past month, to the point that I have to put something under the truck in order to prevent huge oil stains in my driveway.
As a last resort, I picked up some UV dye from NAPA and got a blacklight. It showed all the oil was leaking/spraying out the back, against the firewall and draining down the bell housing, onto the tranny, and onto the ground. I'm thinking either rear main or head gasket at this point, but it appears to be above the head gasket, closer the the valve cover.
I wanted to get your guys opinion before tearing into this, any thoughts? I can post pics if you guys want, but there's not much to see without pulling the engine :/
Oh, and the oil is good, no coolant mixing.

Roark

Have you checked the rear of the oil pan gasket? Sometimes if its leaking in the rear, the oil can kick up and spray. I doubt it's the head gasket because you'd be noticing some definite loss of power. Hopefully it's not the rear main because that can tear up the clutch disk and pressure plate. I'd lean towards the oil pan or perhaps injector leak. Good luck!

aquajake

I figured an oil pan leak wouldn't have sprayed oil that high, but I guess that's why I'm asking you guys After looking at it though, it does appear that the pan's been worked on a bit, as it's pretty dimpled around the bolts.
Regarding the rear main, I have noticed a recent change that I figured was unrelated. When starting it cold, I notice a definite drop in RPM's when I let the clutch out (roughly -200 rpms). Could this be a sign of the rear main going out?

Co_94_PU

iTrader: (-1)

A rear main seal like a front seal puts oil every were when it hits the spinning parts. BUT it's not going to magicly fly thru the bell housing onto the upper head, your rear half moon or valve cover is likely leaking. Get it clean and dry and it should be easy to figure out where it is leaking from. You can check the torque on the pan very easyjust roll under it and see if they are tight.

Oil on the clutch plates will make them slip more not grip more. You should perform the clutch adjustment/tests in the manual. It should fully disengage at I think 3-1" somewhere in there, it's and easy test and not terrible to adjust.

If your clutch is properly adjusted and you still have RPM changes you have main bearing, crank shaft, or maybe throwout(?) issues. Engaging the clutch puts high pressure on the crank shaft, eg pushes forwards, with I forget how many lbs but lots..

aquajake

Thanks, I'm going through the engine compartment today and doing a good spray down and rinse, hopefully tonight I'll be able to take it for a quick drive and determine the location of this friggin leak.

Darryl01088

It's unlikely that oil would spray upwards....Clean the area with brake clean or engine cleaner. Run the car and check with the black light. It should be pretty straightforward .
I suspect it's the valve cover. If you had a crack in the head....you would have major problems, overheating, smoke and low oil pressure.
The valve cover could be warped from overtorqueing. Tighter is NOT always better. Follow the torque spec and tightening procedure. Put the cover on evenly. I have also seen horrific leaks develop when a small piece of the old seal was left in. Make sure it's clean.

aquajake

OK, got it all cleaned up, warmed her up, and took her for a SHORT (100 yards up the road and back) drive. Came back to find oil sprayed all over the firewall. This was all after letting her warm up for 10 mins, the area was completely white before driving. What would cause this amount of oil to spray in a pattern like this, only under stress/high RPMs??? Unless the picture suggests anything different, I'm leaning towards taking off the valve cover, checking for warping, replacing both the valve cover gasket and the half moons, and putting it all back together tomorrow.

Co_94_PU

iTrader: (-1)

Looks likea high velocity spray to me, you wouldn't be getting that out of the valve cover. A clogged passage in the head and a rip in the head gasket would be my guess.

Clean if off again and this time watch it while you're reving the engine by hand, or grab a helper eeven better. One guy mounted his camera and a flash light under the hood to find his leak, you can also try that if it doesn't squirt while sitting.

Which leads to.. Are you sure that is oil, not maybe steering or brake fluid. I of course see you still have paint in the area but it's gotta be something spraying thats no normal leak.

if someone could highlight the oil and water passages in the following phot that would be helpfull, since I'm not sure where they are. And haven't yet found such a diagram.
http://image.off-roadweb.com/f/29222...swap+block.jpg

aquajake

It's oil, and it's definitely spraying, like a mist almost. It's going through a ton of oil, there's a puddle whenever I park, even for just running into the store or something. All other fluid levels are fine. :/ Dang, you guys got my hopes up when you said just the valve cover, now it looks like I'm gonna have to start on the head gasket tomorrow morning

aquajake

OK, after removing the valve cover, I noticed that the spray on the firewall couldn't have come from the HG, as the angle doesn't work; the little squiggly coolant thingy on the back would have blocked the oil spray :/

I took this pic of another 22re that we have in storage. You can see the upper arrow is where the oil stain on the firewall is located in relation to the back of the engine, and the lower arrow is where a leak in the head gasket would be located.

Darryl01088

Oil really would not spray out of the valve cover. It typically seeps. Try cleaning it again and watching it with the engine running at 2500 rpm. Use an inspection mirror.

Co_94_PU

iTrader: (-1)

Maybe check the torque/tightness/seal on the EGR cooling channel, could be getting some extra force from a leak there. Also maybe inspect the PCV isn't clogged, if there is excessive pressure w/ no way out it'll find a way eventually and could then spray out the gasket or half moon.

wireguy

I would check the PCV valve first of all to see if it is plugged or not venting. If there were no pressure inside the engine housing we wouldn't need a PCV valve in there at all. If you think there's no pressure in there that if not vented, could cause a spray at the weak spot, pull your oil cap off and run the engine for 30 seconds with the hood down. Be prepared to clean a lot of oil off your hood because the engine inside is being pressurized by any blow by from ignition compression going past the rings and into the engine internals. If that pressure isn't properly vented, normally done by the PCV valve, it will vent at the weakest link and if there is oil puddled up internally at that spot it will spray it out.

ToyX2

Update??

Jcooley

Hello, call me a dumb ass.. but I do not know how to.post on this site. I have a 83 mint Toyota pick up and one day when I was getting on the freeway I busted my driveline and now I am leaking oil AND coolent. Any help would be awesome because I have no clew, the leek in is coming from the back of the block near the head gasket. So I asume that it is my head gasket? I can not see back there

ToyX2

Tough to say from your discription, pictures might help but maybe not. Best bet is going to be clean it up and then investigate. The busted driveline obviously has nothing to do with it.

Jcooley

Yeah its hard to take any pictures I can hardly get my hard back there to feel it out. I just kind of am figuring maybe when the drive line busted it over revd the engine and caused the headgasket to blow. Olny mantinance I have done to the truck is your typical oil coolent ect. And a clutch. I was just going to go ahead and rip the head of and just dive in aND find the issue