Tacotex

Well, the 4runner is finally showing a little age. It is dripping oil from the tranny/bell housing area, which at 1st guess could indicate a rear main seal. The leak leaves fresh oil about the size of a quarter when parked overnight. I noticed that the leak seems to be higher up than what may result from a rear main leak. Using a mirror to view the back of the engine, I see wet oil starting near the driver side valve cover gasket. I was able to tighten the bolts on the intake side of the cover at the front and back corners (as well as the easier to reach exhaust side bolts), but the others are obstructed by the intake manfold. Its been over a week since I tightened the cover up as much as possble with the intake in place, and the leak seems about the same. From what I can see at this point, it seems like valve cover gasket replacement and/or rear main seal may be needed, but shouldn't have tightening the loose cover bolts at least slowed the leak?. My questions are can a rear main leak throw oil higher than the drain hole at the engine/bell housing interface?, and is there another location higher on the engine I should be looking at other than the valve covers? Wet oil is soaked from the drivers side rear of valve cover down side of bell housing to steering rack area and hydraulic tubing beneath bell housing, and seems to be dripping more from the tubing under the little bell housing drain than from the drain hole itself. My best guess is to pull the intake and go from there, but any advice that would save some labor is welcome.

93Toyota PU

Tightened the cover will not stop the leak in many cases if the valve cover gasket is bad....I recently changed mine and the rubber gasket was severly cracked, which explains the leak I experienced. The torque specs on the valve covers are usually very low, meaning your should not crank them down past the recommended torque. That can cause other problems, including contact with the valve train on some of the 4 bangers.

hross14

I bet it is just the valve cover--And i agree--most people tighten valve covers bolts to tight and cause a leak due to warping or the gasket being destroyed.

Clean up the area and then take a peak again....OR get the additive you add to the oil that lights up with a black light to show you where the leak is.

97ltd4x4

When the valve cover gaskets get hard,There is no tightening them down,they will leak worse.Don't forget there are half moon plugs on the front and rear side of the head,There are also "cam cap" on the rear of both heads,and they can leak oil..They are steel with hard plastic/rubber on the outside,there will be a bracket holding it to not squeeze out of the head,but If you remove the cam cap that retains it under the valve cover,you do not need to mess with this bracket

I just did the valve cover gaskets,cam caps,half moons,also did PVC valve and PCV valve gromett on a friends 99' ,We did the spark plug seals as well,But they were difficult(i am a bit rusty).The best kit to use is this :Beck Arnley 036-1583 Valve Cover Gasket Set: it comes with gaskets,gromets and spark plug seals...Unless you want to piece together the set from the dealer individually.

You can reuse the intake gaskets since they are steel,so all you need is the valve cover set and good quality sealant,I like the right stuff found at NAPA...That or unless you have Toyota FIPG black.

We removed upper and lower intake,removed valve covers,removed pvc& gromett,cleaned w/brake clean,replaced tube seals...

If yours are ok,just lube w/vasoline on the inside,so they slide down the tubs easily..

removed 4 half moon plugs,removed both rear cam caps,removed cam plugs,cleaned up half moons,cam plugs..

used 2 cans brake clean and cleaned rear and sides of heads to remove residue oil,hit w/compressed air to dry..

used right stuff on the 4 half moons grooved part,put sealant all around cam plugs,installed half moons,cam plugs,reinstalled rear cam cap(retains cam plug).

put sealant at corners of cam caps(90* angle where they meet head),installed valve cover gaskets,pcv valve gromett&pcv valve,reinatalled valve covers(make sure not to hit gasket on anything or the gasket might slip out of cover groove)

Installed grommets on bolts,installed bolts into valve covers,tightened them in "X-Pattern"...Just snug will do until the rubber just starts comming out from the steel washer part of the gromett.

Topped off coolant,lost a little from removal of throttle body,you can use hose pintch pliers on both lines and not half to deal with this.

* One word of percaution,as soon as we removed lower intake I stuffed a few rags to cover lower manifold intake runners,as dropping anything down there will ruin your day*

If you do Valve cover gaskets,half moons/cam caps..Now is the perfect time for plugs and/or wires...

Here are some links:
valve cover gasket set,quality parts,NAPA does not stock this set anymore,just the valve cover gaskets:
http://www.amazon.com/gp/product/B000CAVM0A

The right stuff,can find at NAPA and other places:
http://www.vapnapa.com/bk7652427.html

Tacotex

Thanks Guys Sounds like its valve cover gasket time. Sounds better than dropping the tranny...Merry Christmas!

florider

does not sound like this is your problem, but i had some not so tight oil pan bolts at the back ( where pan meets bellhousing ). tightened up about two weeks ago, and no more leak. lucky me. good luck

f L O

hross14

Tacotex--i wouldnt use sealant on the intake gaskets--Like an old mechanic told me

Henry--dont try to out engineer the engineer henry

97ltd4x4

No need for any type of sealant on either intake/plenum/throttle body gaskets,they are steel and will seal fine even after several removals and installs.

logsurfer

I know for sure my leaks are coming from the half moon/cam caps.
are these caps easy to remove? any special tools that i will need?
do they have gaskets too?

stir_fry_boy

You don't remove the half moon caps to do the valve cover gaskets. Put the FIPG on the corners of the half moon on the head. Also, you will notice that there are upside down half moons further toward the outside of the fender of the vehicle (on the heads). These need FIPG also. There is a break in the metal so you can tell where they are. So, there are 4 total places on each head that need FIPG.

logsurfer

stir_fry_boy,

I used that mirror thing and i've confirmed that most of the leak is seeping below the cap. When I remove the valve cover, is this cap easily accessible? from what i see outside this cap is held by a steel tab with 2 bolts.

thank you!

stir_fry_boy

The half moon caps? You do not remove the half moon caps. The half moon caps stay on the head, there are 4 of them on each head (2 right side up inline with the timing belt driven cam, and 2 upside down about inline where the gear driven cam is). The cam shaft runs through the front half moon. It probably is leaking on the corners of the half moon around the timing belt driven cam. When you take it apart, you will see (if it hasn't been done before) brown silicone sealant around where you need to put your FIPG. You have to scrape that off and put new stuff on (Toyota FIPG is black) in order for it not to leak. My valve cover gasket was leaking on the left side rear close to the exhaust manifold.