HELP! FRONT MAIN SEAL LEAKING, AGAIN???!!!

Hey guys...

Been a long time lurker... and rarely post.

I'm having a re-occurring issue with my 4.0L, where the front main seal leaks, spewing oil all over my serpentine belt, pulleys, alternator, etc...

First time, it left me stranded on vacation, and resulted in me towing it to a shop to get it done. The second time, happened 6mths later, and the same shop replaced the PCV, and blamed a blocked PCV for pressure build up in the block, blowing the seal.

This time, still driving it... but gonna have to undertake this again, as it's leaving oil all over the ground.

Is there a known cause for this, besides the PCV? Also, is there a fix that would avoid this from happening in the future?

Any help would be appreciated, at my wits end with this.....

Pic of my Taco and 3rd Gen 4Runner for attention....

 

Nobody? It's literally lasted 20,000kms..... seems excessive.

 

If the same shop has done it twice and it’s failed again.. I probably wouldn’t go back to that shop.. Could be cheap/faulty parts or been installed incorrectly.. I’m not sure about the pcv but I know some vehicles have to have a wear sleeve or repair sleeve put on the crank to get a good seal if the crankshaft is worn down.

 

I read in another post, that this may be the issue, and someone did chime in, saying a sleeve may be necessary to remedy the issue. I brought it to the same shop today to pick the owner's brain. He mentioned that the last seal was not OEM, but would order an OEM piece today, along with a sleeve, in case it's worn down.

That being said, I told him that the seal shouldn't be failing after 20,000 kms... there has to be another issue here. The issue I have here, is I'm extremely limited on where I can bring this truck to. I'm in a small town of 5000 people, nearest Toyota dealer is 2.5hrs away, and only 2 garages that aren't Chevy, Dodge or Ford dealerships. lol

 

A front main seal shouldn't require a brand specific shop. It's not like you are having a trans or rearend rebuilt.

Definitely use an OEM product which is made by NOK. So if you buy it on Amazon or Rock Auto, NOK is the same shit you get in the little Toyota baggy over the counter.

I've seen plenty of high mileage Toyotas and I can't recall one with a really chewed up balancer requiring a sleeve. Not to say it doesn't happen but it's rare.

Now a blocked PCV can do that but again very rare.

My vote is they used a crap aftermarket seal or drive it in wrong. I just did a crank seal on a standby generators that had a part of the lip bent over backwards from the factory.

I'd buy an NOK seal and do it yourself. The hardest part is getting the balancer off. Get a good puller.

 

Thanks for the sound advice man... I'm just not confident about tackling this right now. I recently pulled my driveshaft and attempted to do the U-joints and carrier bearing. Ended up destroying 2 of my new u-joints, busted my lip with a pair of channel lock pliers (trying to get a cap off the old u-joint), and ended up bringing it to a garage, because I couldn't get the caps to seat properly in the yolks. lol

 

At least you’ve got that sweet ass 4Runner to drive in the meantime

 

That is how you learn to do it. Start with small projects and work your way up. I spent many Saturday nights fixing my junk as a highschool and college kid so I could go work on Sunday.

I once smashed my finger, not sure how I didn't break it. Took a full swing with a 32 ounce ball peen changing ujoints on my Samurai. I slipped and hit my finger that was holding the socket on top of the cap. Spent two hours with my hand jammed in the frozen peas inside the freezer.

Point of the story, I now hold the socket with a vice grip when hammering out ujoints!

 

My bet is on a scored crank pulley/balancer. If the interface there isn't perfectly smooth, it'll tear up a seal, any brand, in short order.

 

Not even man... I park this old girl in the winter.... and we still have a about a month left of this white shit. lol!

 

What would cause that?

 

The steel internals of the seal actually wear a groove in the pulley interface, causing an oil leak. Thats pretty well documented here if you do a search. Or...one little burr can prematurely wear the seal, too, if the mechanic wasn't careful removing and/or reinstalling the pulley. I would remove and check the pulley and if it's not perfectly smooth, replace it or re-sleeve it before trying again with a new seal.

 

i agree

no less maybe a bad balancer itself ........... if its ' wear ' no doubt other crank elements are worn

big end bearings

crank thrust bearing

resulting in out of round ........movement ....... vibrations

 

You're right. Could be a wonky balancer/pulley that got damaged from debris, etc. I had a weird vibration that ended up being a small pebble worn in to my timing belt on my 5vz-fe. No idea how that could have gotten there and stayed where it did. But my money is still on a scored balancer pulley shaft as this wouldn't be the first time it's happend to someone here (myself included on our 2006 DCSB). Afterall, the big end bearings are pretty robust on these motors and you would notice that kind of vibration before you could even worry about an oil leak.

 

My guess is the shop didnt put the seal in correctly,and used a cheap junk aftermarket seal.

 

They for sure, used an aftermarket seal. This time... we're installing an OEM one. Just waiting for it to come in, and we'll also be putting a wear sleeve in there, if needed.