3RZ Oil Leak

1999 3RZ Automatic
I have been chasing some engine oil leaks for quite a while. I am assuming that most of these leaks are due to the age of the seals in the engine, after about 20 years these things start to break down.

Roughly 2 years ago I had my local dealer at the time fix the oil pan gasket, crank seal, and valve cover gaskets. About 6 months later I took my truck back to them because it was still leaking. They put in dye and determined that it was still leaking from the crank seal and oil pan. They therefore replaced these AGAIN. In the process they had to BREAK the oil pump to get it off, so I got a brand new oil pump out of the deal. I'm assuming that the tech didn't use an impact to remove the screws.

I replaced the oil filter housing gaskets myself.

Flash forward to now, I still have an engine oil leak that appears to be coming from the oil pan. I'm not sure how Toyota could mess it up TWICE, so I am thinking something else is going on here. I recently did a cross country move and there was oil covering the right side of the oil pan, transmission pan, and steering rack. I completed de-greased the engine the best that I could and put in some UV dye. After that I drove around for roughly 50 miles and I can already see the oil coming out.

At this point I'm trying to determine if the leak is coming from the rear main seal or the oil pan.

This photo is of the passenger rear corner of the oil pan looking towards the rear of the truck. You can see the transmission cooler lines on the left.


This photo is of the bottom of the bell housing at the inspection cover. You can see a small amount of green here, this is new oil. There is oil around the edge of the inspection plate, but I don't believe this is new, just stuff I didn't clean off earlier.


I removed the inspection plate to look for oil in the bell housing, but I didn't see any on the flywheel. There was some residual oil in the bottom of the bell housing, but it's hard to tell if this is new or not. I did not de-grease this area when I was cleaning.

My question is, if I had a rear main seal leak, would the flywheel have oil on it? I've rear that it would tend to fling oil around inside of the bell housing, is this true?

I did snug up the oil pan bolts at the rear since they were pretty loose. I know these are 9ftlb, but I'm assuming that's dry and not with oil on them. Therefore it's really hard to tell if they were loose enough to cause a leak.

 

Man that sucks. It should be surprising that the service dept at the stealership didn't get it right twice, but it doesn't surprise me.
I'm thinking along the lines of what you're thinking with regard to the oil leak. I don't have experience with leaks there at the crank seal but I would think it would fling at least a little bit of oil there in the bellhousing. I would think there would definitely be enough oil collected there at the bottom if leaking from crank seal. It wouldn't surprise me if the pan is leaking again, that same pan leak those mouth breathing knuckle draggers 'repaired' for you.... Twice... Now a third time. Amazing to me places like that stay in business

 

I'm hoping it's just loose bolts. When I went to tighten the rear ones I realized why they could be off. It is difficult to get a torque wrench on the rear ones because of the bell housing and flex plate being right there.

If I can determine that it is the oil pan leaking again, then I will most likely buy a new oil pan. The only thing that I could think of that keeps causing this would be if the pan was warped.

 

Are you sure it calls for a gasket and not just cleaned spotless and using the toyota sealant,,, I know there's a break in time when car manufacturer's went to the sealant away from the gaskets, it depends on the design of the mating surfaces. Just a idea.

This is just some info if you didn't know this already. I have no idea if your year model calls for a gasket or not, just a general FYI

If it does require a gasket, there's a procedure for straightening the flange on the pan where the holes get dimpled from over tightening and it cuts the gasket.

 

Oh the oil pan is definitely Toyota FIPG (form in place gasket) aka RTV. The only people that have ever touched it have been the dealer, so you’d think they would know what to do.

 

i chased an oil leak on my v6 and after replacing the oil pan, valve cover gaskets, half moons, it turned out to be the rear main seal. from the looks of your pictures its the rear main seal.

 

mine had a bad leak, and looked just like those pictures, the fly wheel on mine didnt have much on it, but the starter did, and it leaked onto the rack and pinion.

 

This is good info man. I would have thought more oil would be flung around the bell housing, but I guess if it leaks a small enough amount it will just slowly find its way out without flying all over in there huh?

 

well while it spins the oil gets shot up to where the starter is at, and then it leaks down. when I removed the transmission plate, my flywheel looked clean. it was a pain, after doing all the work myself, I took it to a shop I trust and he replaced the real main seal for 500 bucks which I think was awesome, I hear on a v6 its a pain to replace. for oil pans, I used the Toyota black rtv, and it is very dry under my engine. I also installed a small hose to re-rout my AC condenser line so the water can drip away from the engine area, so that would be confused with another leak.

 

use only oem rear main seals, I made the mistake of using a after market one before my engine was installed, and it leaked within 4k miles.

 

I agree with you fully. And I'm glad you're posting up your experience with it cause it's gonna help a lot of folks as we're coming up on that age on these tacos where we gonna see mains start to leak more and more common

 

So I decided to buy a cheap inspection camera so I could look at the rear main seal. I could instantly tell that it's leaking. It must not be a fast leak since it just runs down the back of the block to the oil pan.
It's not worth it to me to try to replace this unless I'm pulling the transmission for some reason.
I might try some of this stuff and see if it helps https://barsleaks.com/product/concentrated-rear-main-seal-repair-1040/
I've read a lot about it, and it's not like other stop leak chemicals that clog orifices in the engine. It just makes the seals swell a little.
I'll also switch to some high mileage oil on my next oil change.

While I was looking around the engine for more leaks, I decided to unbolt the ignition coil mounting bracket and clean around it. This has always been covered in grime, which I assumed was from my valve cover gasket leaking. Low and behold, the distributor plug, is the source of this leak. Here is a photo of it after I wiped away the grime. This is the plug that covers the hole where a distributor would mount (95-97).
You can see oil starting to seep out already.

EDIT:
Just found the part number 90339-36001
It is called the "valve cover cam plug"

I skimmed through the FSM but I didn't see mention of this. Does the valve cover have to come off to replace this?
I did find LCE selling a plug, but this is for upgrading a 3RZ to coil packs from a distributor.

 

You gotta be kidding, the 'rear main leak' was from this distributor hole plug deal this whole time? I gotta look at a diagram to make sure but looks like it could be a real easy fix with some FIPG or similar. It's just the machined hole where the distributor was, correct?
Edit: just reread your post and saw this is a seperate leak you're referencing. You did in fact see the rear main leak with the camera. I follow ya now.

 

I don't know man, the half moons leak a lot, this might just be one leak, I doubt the half moon leak would get into the flywheel area. just saying....

 

yep, separate leak that I never knew was there. I ordered the part and some fipg, I just don’t know the procedure for removing it. I’d rather not pull the valve cover. I’m thinking I can just drive a screw into it and pull it out, but once I do that there’s no turning back haha.

half moons are fine(those are different than the plug where a distributor would be). Most people don’t know that plug exists because it’s behind the bracket that mounts the coils, and you’d never need to remove the bracket for anything.
The rear main is definitely leaking, but I’m not pulling the transmission to fix it.

here’s a pic of the rear main leak from the inspection cam

 

Sounds like a reasonable plan to me

 

yea I agree, dude your main seal is leaking, hate to be the bearer of bad news, and when it happen to me I was like... nahhhh maybe its just.... save yourself some time and start with the rear main seal.

 

Haha yea it’s definitely leaking, but I’m pretty sure it’s been leaking for the last 10 years. And it’s not a lot, not even noticeable level drop after 5k miles.

 

That dude got banned quick?! The dude that responded before me?! Isn't that what the line through his username means? Banned?

 

Yeah just checked. He got a 3 day ban for something to do with selling stuff on here. Doesn't say specifics. Hopefully he sticks around, he's got good experience and input