The most likely culprit in a 4-cylinder manual 2wd Toyota 4Runner leaking motor oil?

[mom]

Lately, there is a small pool of Mobil1 10W40 motor oil underneath the engine of my 4-cylinder 2wd Toyota 4Runner.

It doesn't leak much - just a few drops, perhaps twenty or so drops overnight. In fact, the oil level doesn't seem to diminish much over time (surprisingly) so I'm not really sure what the problem is.

What I'll do is buy some Gunk engine degreaser, get the engine nice and hot, drive up on ramps, and spray it down and wash it with water.

Just so I can 'see' where the oil may be coming from.

I've already changed the oil, so I know it's not coming from the filter itself but it could be any number of gaskets (that I don't know anything about).

May I ask WHICH is the most likely culprit in a 4-cylinder manual 2wd Toyota 4Runner for leaking drops of oil while parked overnight?

 

[mom]

Doing a search, I see the main culprit is the oil filter itself.

• Maintenance > leaking oil, help!!!

Is your oil filter on tight?,did you change it recent?

And, it seems that the oil pan bolts are another potential cause.

if you suspect it might be your oil pan try to tighten the nuts down a little

Some say the "valve cover bolts" loosen up.

• 3rd gen T4Rs > Valve Cover Gasket is leaking

every 5VZFE engine I've had my hands on ... the valve cover bolts were loose ... so, just tighten them up with a 10mm wrench, you should be fine. But you can only reach about 7 of them without taking out the intake.

 

[steezemcqueen]

Valve cover gasket, oil pan gasket, rear main seal, and front crank seal are the places I would start. You should be able to narrow it down at bit just by where the oil is on the engine. For instance, if there is only
oil near the bottom of the engine and not halfway up it like near the valve cover, it's probably not the valve cover gasket

 

[YotaZach85]

The oil filter extension housing has O rings that go bad quite often but the pan, front and rear seals are also good places to check out, I never had a valve cover gasket leak on mine in 255k miles though.

 

[attitudeofgratitud]

The oil filter extension housing has O rings that go bad quite often but the pan, front and rear seals are also good places to check out, I never had a valve cover gasket leak on mine in 255k miles though.

X2

Front Crank seal and oil filter housing

 

[mom]

The oil leak is getting worse in my base manual 4 cylinder 2WD 4Runner - I had to put two quarts in today.

I had bought cans of engine degreaser and sprayed it all over the bottom and top but I still I couldn't find where the oil is coming out from once the 4runner was driven a bit.

I'm spraying again this week to try again.
I think this is the final list of key culprits to suspect in this order:
0. Oil drain plug, oil filter gasket
1. Oil filter extension housing o-ring
2. Oil pan gasket
3. Rear main seal
4. Front crank seal
5. Valve cover gasket (and front & rear camshaft covers & housing plug to the rear of the camshafts)

I think the location of all but the rear main seal and front crank seal are self explanatory. I'll look up to see if I can find a diagram or picture of those two seals.

EDIT: Looking for a picture of the front and rear seals, I find these threads:
Rear Main Seal or Oil Pan Gasket Leak (no pictures)
a. 6 hours labor for each seal
b. Best to use oem seal

Rear Main Seal Question (no pictures)
a. No additional groove or sleeve for the rear main seal (RMS)
b. Don't drive the seal in all the way
c. Use OEM seal only
d. Good mechanic can do the job in 5-6 hours

new rear main seal still leaks (no pictures)
a. Fel Pro seal was sealed with RTV but still leaks (grooved crank?)
b. OP said he may sleeve the crank
c. OP said OEM seal worked, after greasing
d. ChildrenOfBodom said the same thing happened to him
e. Unfortunately for the RMS, you remove motor or drop transmission
f. To drop transmission, FSM says remove sway bar & exhaust but that's optional
g. 11 hour job, need transmission jack

2000 4Runner - Rear Main Seal Leak? *Help!* (no pictures)
a. A large leak will affect manifold vacuum

write up for rear main seal (no pictures)
a. OP is looking for a RMS writeup
b. Remove transmission & flywheel, R&R the seal, perhaps sleeve the crank
c. References 3.4L Oil Leaks (150k) - Page 2 - YotaTech Forums

Rear main seal replacement inquiry (no pictures)
a. $1,300 job at Toyota to replace RMS

Pretty sure I have a leaky Rear Main Seal
a. disconnect driveshaft, undo bell housing bolts and linkages, drop tranny crossmember.
b. Chadman refers to: CYi5's '99 4Runner Buildup - Page 15 - Expedition Portal Forum but that's for the 4WD

rear main seal leaking questions ? (no pictures)
a. Nobody replied

changing the rear main seal... (no pictures)
a. Rather slit my wrists before doing that job again

leaky rear main seal?
a. Implies that the use of Mobil1 oil cleaned out the sludge around the rear main seal

rear main seals (no pictures)
a. $1,100 dealer repair for RMS

Rear Main Seal (no pictures)
a. Pour oil additive seal leak into the engine oil?
b. 8 hours to drop the transmission

YotaTech 3.4L Oil Leaks (150k)
a. VCG is a PITA because you have to remove the intake
b. Make sure you seal the camshaft covers (use a mirror for the rear CSC)
c. Use Toyota black RTV (not Advance Auto Parts black RTV)
d. When doing the valve cover gaskets replace the gromet for the PCV
e. Use Felpro VCG
f. 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
g. Buy FIPG from the dealer (whatever that is)
h. Don't forget the cam cover plugs
i. Toyota FIPG and Grey RTV make for a great and lasting seal
j. Replace spark plug grommets while you're there

Is This The Rear Main Oil Seal?
a. Pressure wash first to find the leak
b.Use blacklight dye to pinpoint the leak

oil leak problem (no pictures)
a. There are ultraviolet leak detectors you can buy

 

[T4R2014]

That diagram is a 5VZ. ^

You could also check TacomaWorld since they have more 3RZ's.

 

[mom]

That diagram is a 5VZ.

Thanks for pointing that out. I removed the offending diagram so as not to lead anyone astray.

BTW, I was shocked and amazed I could not find representative photographs of each of the five different types of common oil leaks on this forum, but, maybe my search just missed them.

To that end, I snapped a dozen pictures of 'my' oil leak, which I will post tonight as I have to pick up the kids from school right now.

It would be nice to identify pictorially (or diagramatically) the five locations to look for oil leaks. Mine seems to be on the passenger side but that's about all I can pinpoint visually.

It's NOT the oil filter itself, not the drain plug, as they're both dry, and the rear seal area (if I am looking in the right spot) appears reasonably clean. Also directly under the harmonic balancer appears clean, however just after that, on the engine, it's soaked - but I can't tell if it's the oil filter housing gasket, or if it's the valve cover gasket, or the oil pan gasket.

Pictures to follow tonight.

 

[mom]

From these pictures, where would you suggest the oil is leaking from?

 

[mom]

What can I do to narrow down what exactly is leaking all this motor oil?

 

[BURNINGAIR]

From the pics I would do the oil filter and oil pan.

 

[BURNINGAIR]

Looking closer, did you jack the truck up using the oil pan? Maybe hit a rock with it? The marks on it would suggest something happened... Anyways, do the oilpan atleast. Possibly replace the pan.. But take a good look at it furst.. The marks dont seem to be enough dmg to need a whole new pan, but maybe the gasket

 

[KidVermicious]

I second Burningair - oil can climb dirt, so don't be fooled by oil slightly above the pan.

 

[mom]

Thanks for looking at the pictures to advise me as I've never done anything like this before.

Taking your advice, I will replace the oil pan gasket after looking for 3RZ-FE 2WD DIYs (I have the FSM and the Haynes also, but in general, they skip zillions of steps).

One other wet spot that worries me is this spot a few inches above the oil pan gasket:

I really don't know what 'part' it is, and it's hard to snap a photo of, but here are some full-sized photos if you can help me identify why this part above the pan is very oily.
http://www3.picturepush.com/photo/a/11967986/img/11967986.jpg
http://www4.picturepush.com/photo/a/11967987/img/11967987.jpg
http://www2.picturepush.com/photo/a/11967990/img/11967990.jpg
http://www5.picturepush.com/photo/a/11967988/img/11967988.jpg

 

[nevada]

that engine uses a timing chain, correct?
it may be the timing chain cover that is leaking.

i think the oil filter mount/adapter is suspect aswell.


and that last thing is just a mount bracket. has nothing to do with oil. its just wet from somewhere else.

 

[kball]

Your passenger side valve cover gasket is leaking so I would start there. Clean it all up really good and then just run it enough to get the leak started so you can hopefully tell where it's coming from. Maybe get some of that dye you put in the oil to use with the light.

 

[mom]

Maybe get some of that dye you put in the oil to use with the light.

I've heard (in the threads) about the UV dye - which I guess I should get as it will show me the first bit of oil seeping out.

I'm beginning to think there are three culprits at the moment:
1. Passenger side VCG is 'slightly' leaking (I don't think it's the biggie though)
2. Oil filter housing seems to be leaking the most (I think)
3. The oil pan gasket on the passenger side is very wet (but it may be #2 above it).

Does it look like an OFH leak to you?

Here are some full-sized pictures of the oil filter housing.
http://www3.picturepush.com/photo/a/11971501/img/11971501.jpg
http://www4.picturepush.com/photo/a/11971502/img/11971502.jpg
http://www5.picturepush.com/photo/a/11971503/img/11971503.jpg
http://www2.picturepush.com/photo/a/11971505/img/11971505.jpg
http://www3.picturepush.com/photo/a/11971506/img/11971506.jpg

 

[nevada]

theres more to it than just adding the dye.
but, i agree a leak detection system would be a good idea.


it does look like the oil filter adapter is leaking. i think its a fairly simple fix. id start with that.

 

[JohnsD90]

If you figured out where the leak was coming from, then why make a thread, just order the gasket and replace it, its pretty simple. But if it leaks less than a quart in 5000 miles, then it really isn't something important, but leave it at your own risk, but you have a safe 1 quart float on the dipstick.

 

[mom]

If you figured out where the leak was coming from, then why make a thread,

Good question.
I don't know where the leak is coming from - hence the thread.

Also, every thread I start, I want to be a reference for the next person who, like me, is clueless when just starting out - so that they too can get the job done (It's why forums work).

For you this may be simple; but for me, I've never replaced anything with a gasket before.

All the work is usually in diagnosis (not in throwing parts at the problem).
I am still just in the diagnostic stage, which is why I ask for your advice.

Moving forward, we've found the six most likely causes, and we've looked at all of them (at least superficially) to narrow it down to three possibilities.

I'll look for the UV dye in the auto parts store to better diagnose where the oil is leaking from.

just order the gasket and replace it, its pretty simple.

Simple for you perhaps ... but I have no idea (yet) how involved it is, and, there may be more to it than just replacing a simple oil filter bracket o-ring or oil pan gasket.

The diagnosis & replacement probably entails knowledge that I need to learn (and will try to find out), like what each gasket does, what's the best gasket to use, and whether to use sealant, and how to perform the task, and what else to do there while I'm at it.
...
Wow. Searching this forum came up blank on a DIY for the oil filter housing gasket replacement. I'll keep looking...

From this yotatech thread, I find the official name to search for the DIY:
"the FSM calls it an "oil filter bracket" and it looks like there is an oval shaped gasket and an O-ring to seal the mating of the block"