CYi5

Engine has 150,000 miles. Mobil 1 since 125,000 when I acquired it. Any ideas? Valve cover gasket on top? Oil pan gasket on bottom? Rear main seal X-( ? Please help me diagnose! I've done the oil pan gasket and valve cover gasket on a samurai, is this a shade tree job as well? The oil spots look similar to that situation which has me guessing those options.


Oil around cap.


On top around PCV valve.


Rear passenger from top.


Dripping down on steering rack.


Bottom of Bellhousing.


Above bellhousing driver's side.


Closer view of above bellhousing drivers side.


Passenger side rear oil pan.


Close up rear oil pan.


Passenger side looking towards rear of oil pan and faceplate of bellhousing.

arjan

The passenger side valve cover on my '97 has a leaking gasket also. Ironically I've also ran mobil 1 for the last 100k km or so.

WEINERDOGBONE

iTrader: (1)

You may have more than one leak. I'd do the valve cover gaskets first. Clean it up and then check that bell housing again after a while. I have a rear main leak that looks like that. Maybe you'll get lucky.

The valve cover gaskets are a total P.I.A. because you have to remove the intake to complete the job. It's not hard though. I'm going to tackle my rear main seal this summer.

CYi5

Yea i'm not worried about the valve cover gaskets, everything is on top and easy to see and work around. It's the oil pan that makes me nervous...probably removing the front diff. Someone also mentioned I may have to jack up the engine slightly to drop the pan..

YellowTT

Don't worry the valve cover gaskets is a very easy job. Just make sure you also seal the camshaft covers. This is usually a major leak point for the 3.4L but the job itself is very easy just take your time if not familiar with this engine. Let me know if you need more info. Based from your pictures I would start at the valve cover gaskets. Use a mirror to check the cam covers at the rear of your valve cover gasket while the truck is running.

You may have multiple leaks

CYi5

Do you think the leak could be bad enough up top to drip all the way down to the bottom of the oil pan? You can see it's pretty well saturated up there:
The oil on the bottom of the oil pan seems pretty fresh (and looks like it's coming from that seam ) I just really don't want to drop that pan.

CYi5

When you say 'camshaft covers' which part are you describing?

YellowTT

based on your pics labled top of bellhousing and below the bellhousing it looks like the cam cover are leaking. You can see the cam cover on those pics. I tried to crop your last pic from the repair manual hope it worked. On this pic there is a part referred to as the rear plate with a round component in front of it called a housing plug. The housing plug is the part that I was refferring to. The semi circular plugs should also be removed, cleaned and re-sealed with proper RTV. The toyota black stuff is te best but you can get the grey import RTv from Advance Auto. Do not use the black RTV from advanced auto if needed I can explain later.

CYi5

Thanks for the reply, your info as well as this thread should help me get it done tomorrow. I guess i'll jump right in and do both sides. I picked up the two gaskets, spark plug tube seals, and pcv grommet this evening. I believe I do only have the ultra black permatex gasket maker, that's no good huh?

logsurfer

get the fipg from the stealership, worth every penny imo. I recently replaced mine and no leaks so far.

brazos609

How did you get pics of my engine? I have had a valve cover gasket set sitting on my bench for months because I just know that won't be enough to take care of the leaks. I am tempted to have a compression and leakdown test done first to get an idea how the internals are and then pull the block. That would be a good way to take care of alot of things at once; valve cover gaskets, mail out fuel injectors for service, pressure was the whole engine, oil pan gasket, rear seal, maybe installing header? If the compression and leakdown test showed a problem I would just pull the heads or do a rebuild if needed.

logsurfer

Fixed my leak coming from the valve cover gaskets but i found another leak similar to the pics above. they seem to be oozing out of the bolts of the face plate. Can I just remove the bolts and replace the faceplate? I hope it's that easy...

CYi5

Na the only thing behind the faceplate is the "flywheel" for the auto tranny. When I took my plate off the wheel itself seemed dry with no oil residue on it. I took that as a good sign, i imagine that would be wet if it was a main seal going...I cleaned everything off and looked again today and the oil is back where it was before, around the oil pan and on face plate .

cackalak han

Never have witnessed this but is this the result of going to synthetic at a higher mileage?

YellowTT

FYI
Yes, when doing the valve cover gaskets replace the gromet for the PCV. Make sure the PCV line and port to the manifold is free of any restrictions/blockage this can cause a leak in the near feature as the pressure starts to build.

Good Luck and let me know if you have any ?????s

FYI
the toyota RTV and the grey RTV designed for imports handle the highe temps better and vibrations caused by higher reving engines. Your stuff will work but at a later point may need to be reapplied.

J'S LTD 4RNR

Most definately valve cover gasket leak. Looked itentical to my engine bay.

Red_Chili

Mobil 1 will find its way past marginal seals. DAMHIK.

cackalak han

I found Mobil1 was very thin compared to other oils. In my Hondas, I got maybe 1/2-1 qt loss with M1 every 2-3k miles. Switched to Amsoil and Valv Syn and never had that problem. Haven't used M1 since.

CYi5

Valve cover removed, condition after 150,000 miles. The old valve cover gasket is still in place and later came off easily.


Removed and applied new gasket material to semi-circle plugs.


Applied new gasket to the corners where they are known to leak after removing old glob in corner.


New spark plug tube seals hammered in. Remove the old ones by using a flat head screwdriver to pound the metal ring inwards, then punch out from the outside.


New gasket in place. The felpro brand fit very snugly, I had no issues with it falling out.


Put in a new PCV grommet as well while I had the cover off. PCV valve was still operating correctly.

Worth noting is that a major leaking spot on the 3.4's is the housing plug to the rear of the camshaft. It is covered by the rear plate. To access this you must unbolt (2) the rear plate from the back of the engine as well as unbolt the last bracket holding the plate in. From there, just grab the plate and wiggle it out. I put gasket material all around this and then bolted it down tightly. Big thanks to YellowTT (yotatech) for bringing this to light, it will definitely need to be done on the opposite side when my intake plenum gaskets arrive. (Will update with pics of those components at that time.)

logsurfer

This is what i thought too, but from further investigation and with the help of stir_fry_boy,
I discovered that the leak is actually coming from one of the corners where you need to put the fipg,
then leaks down to the housing cap.But what the heck, good job on making sure its oil tight.

I see from your pictures that you didnt cover the plastic wiring harness with tape.
That worked for me on the passenger side. But take my word, you will not be so lucky with the drivers side. Trust me.

btw, the picture below tells where my leak is coming from. maybe this will help you too. I cleaned the area and used the remaining fipg
that i had and put some on the area inside the red polygon. waited for it to dry then drove it around. No leaks so far!