Crank Seal Oil Leak Opinions

Man, have i been leaning on you guys HEAVILY… Back at it again with another “please help me identify a leak” I am 95% sure it’s a crank seal that went tits up, but i would love some opinions from people MUCH smarter than i..
06 4.0 4x4
189k
i hadn’t noticed a leak until my most recent CV axle change.. judging by the grime build up from what appears to be the Mesozoic Era, i’d say it’s been dripping for some time.. never enough to register on the dipstick between changes. Any advise is greatly appreciated.
straight on with the pulley

under the bumper facing aft towards pulley

Power steering pump

 

I had a similar leak and it was my crank seal. I noticed it when I was driving one day with my windows down, I could smell oil and didn't think anything of it until the next day and I had a small puddle of oil under the truck. Fairly easy job remove fan/shroud and used an impact to take off the crank bolt and pulled the oil seal out. It still looked ok but a new seal fixed my leaking.

 

Thanks, man!

 

There’s other things that can leak.

leaks travel downward due to gravity, and rearward due to the car moving forward. Not to mention pathways of the engine shape, and things spinning because the fan.

usually, a working PCV system applies vacuum to the crankcase helping keep oil inside. Versus excessive crankcase pressure from a bad PCV system forcing oil past seals to leak.
Depending on the car.

that being said. It is old. And has miles. It wouldn’t be crazy for the seal to be bad. After all, the rear ones go and people change those whether they’re bad or not. And rear may be harder to access.

if you’re in doubt, there are multiple diagnostic steps that can be done.
-clean and re evaluate
-UV dye into oil
-component removal to inspect
-doing other repairs one at a time and re evaluating
-clean, dry, spray foot powder. It changes color when it gets leaked on

that other thread where the guys crank pulley went bad has me paranoid wanting to change mine preventatively. If you decide to do the same that may allow you access while the pulley is off to change the seal.

I don’t know off the top of my head what is involved. But I imagine it’s simply
-remove belt
-remove pulley
-replace pulley bolt / crank dampener
Providing access room to the seal
-re assemble, line up the pulley, torque bolt to spec
-possibly oil drained during this

If it was German there would be 2mm room, no ability to take that picture, and require removal of entire front end

last time I did a main seal was rear. Followed instructions of sealant cure time
-clean and prep
-used a Teflon-lined seal that advised to let sit a minimum of 4 hours prior to any turning over of engine
-installed inner PTFE onto crank
-then to be gentle turned over by hand to start the depositing of the PTFE prior to actual start up which is faster spin rate
(Teflon seal is said to wear less of a groove into the riding surface of the crank)
-use tools if I have them, if not made one out of a soda bottle cut to slide the seal on; had to walk through grocery store until finding the right shape size plastic bottle
Etc

on a vehicle that DOES have sensitive PCV system, leaking main seal can sometimes be also confirmed by
1. Equals vacuum leak and CEL
2. Spraying brakleen on it while running causes change in idle

 

posts like this is why i ask questions here. Thank you!

 

Also OP I would just like to add I am like 99% sure that is your crank seal, for some reason it seems some of these trucks have issues with them. Not the first one I have seen go bad. For reference my truck is a 2014 and it went out at around 115k. It's tricky when looking at the residue but I took a chance on mine and it was correct. I think with the crank pulley spinning it flings oil all over the place. Quick little tip if you do end up changing it yourself, I used a bit of grease to help hold the spring on the inside of the seal. Much less risk of it coming off while installing and possibly falling into the front cover

 

honestly I’m curious about those springs. I’ve never messed with them but recently saw a video from a reputable shop where guy put dabs of sealant inside on the spring area claiming it will basically help keep the spring from falling out forever (at least for the life of the seal itself)

might try that trick next time, I don’t see how it done carefully would hurt anything.

or even grease versus nothing at all tends to stay liquid (provided it’s not corrosive and doesn’t thin at temp) and hold things versus dry

sometimes seal install (without cover removed and on a bench to inspect) requires tapping it in to final position after it’s initially slid on, which if the spring isn’t secure could knock it off.

 

It's an old school trick to keep the garter spring in place while tapping it in with a seal installer. The worry is it will pop out from the shock of tapping it with a hammer. Once it's in there with the crankshaft slightly spreading the seal the spring isn't going anywhere. Back when I was doing timing belts a lot I'd pack a bunch of dielectric in there.

 

Yea I think it's just to help keep it in place, once the seal is where it needs to be the spring shouldn't come out. I did it because my buddy that is a mechanic told me to do it, he also told me to use locktite on the OD of the seal. I used grease and he told me why that wouldn't help future leaks but honestly I didn't want to have to deal with cleaning out locktite if this seal ever goes bad again.

 

I mean maybe. The OD is not as critical. Have put the OD dry before as well as with a thin film of oil.

ideally a good main seal is gonna last 100k or more, including a new next one.
Any seal is going to dry wear eventually.

 

I would change the belt while you’re there too man !
Looks to be some cracks on the right sid rod the first photo.
I wouldn’t let one go more than 100k even if it’s crack free.

 

Hmmm, I'm at 158,000 miles on my stock belt and it isn't cracking yet. I just checked it last week. Do these belts begin to shred when they fail, or do they just blow? I even have new spare idler pulleys that I've had for a couple of years now but my truck just keeps ticking along.

 

They can get thin. You can tell by looking at the tensioner arm, it'll be clocked farther to the side taking up the extra slack. And sometimes you can tell just by looking at the belt sitting in the grooved pulleys. It will be "sunken" down in the pulley because the belt is thinner

Sometimes the stitching comes apart

Hasn't it made any squeaking noises yet? I probably would havreplaced it when you did the idler pulleys. If it breaks on the road unexpectedly it'll be an inconvenience to say the least

 

I've never actually had one fail on this truck, but other cars I've had will shred and just get frayed.
I don't think they would snap unless it's way too tight (wrong belt), at that it'll probably just wear out pulleys fast if it's only a bit too tight in a manually tensioned system like the 5vz's.
I figure they're cheap, easy to change. not worth being stranded if I'm out in the middle of the desert or far away from home!

 

This too.
Mostly I've seen ones that just get worn and stretched and have less than optimal tension on them.
my rule of thumb is you should be able to rotate it 90 degrees on the longest run between pulleys by hand, but not further, or like 180 deg.

 

I replace the PCV and check the hose for cracks every 40-50k on my vehicles. They are always still rattling when you shake them, but they never sound as good as a brand new one and they always have some sludge on/in them even with 5k oil changes. Hose cracks=vacuum leaks. Very inexpensive part with a tough life and dirty job to perform, especially living in a valve cover: oil vapors and moisture, cold winter temps.