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Discussion Starter · #1 · (Edited)
So about this time last year I was doing an oil change and noticed oil hanging from the bottom of the transmission housing. Took my ST to the dealership and they diagnosed it at the rear main seal and it was repaired under warranty. Just got under my car today to do an oil change and guess what? Rear main seal is leaking again in less than 7k miles. This time my clutch is feeling like it's slipping so I'm pretty sure it's fouled. Any ideas of what would make the rear main seal fail repeatedly?

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Rear mains are a pain.

Could be from crankcase pressure, caused by any number of things. Possibly bad PCV valve or some other blockage. Put a vac/boost gauge on the crankcase and check.

I had one I never could figure out that ended up being a small nick in the crank eating the seal.
 

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How hard are you driving the car? Almost any engine will leak a bit out of the rear main if you're stomping on it. Drive easy for a week and check to see if it's leaking.
 

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So about this time last year I was doing an oil change and noticed oil hanging from the bottom of the transmission housing. Took my ST to the dealership and they diagnosed it at the rear main seal and it was repaired under warranty. Just got under my car today to do an oil change and guess what? Rear main seal is leaking again in less than 7k miles. This time my clutch is feeling like it's slipping so I'm pretty sure it's fouled. Any ideas of what would make the rear main seal fail repeatedly?

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Not entirely sure, normally accidents or front end trauma seem to cause leakages, but if you don't have such a history then idk.

As stated above though, any kind of flaw on the crank would eat up the seal. In a perfect world the Ford tech would have thoroughly inspected both the crank end, and the sealing surface in the block. Which I highly doubt, given today's trends in auto repair.

I wonder if @PA_LE has any luck on his second rear main...

How hard are you driving the car? Almost any engine will leak a bit out of the rear main if you're stomping on it. Drive easy for a week and check to see if it's leaking.
Huh? This is a statement I have never heard anything about, never experienced firsthand, and am highly skeptical of in its entirety.

A motor in good health should not be leaking oil from the rear main seal at all regardless of how you drive it. It's a seal, not a "oh lets weep a bit of oil when the crankcase pressure increases".

In all my years, and all my cars, I have never seen this to be true. I drive the **** out of all my cars. Wrench on all of them, and have never seen this come to fruition.

If driving your car spirited is causing your rear main seal to leak, then your motor has issues. Either PVC issues, blow by issues, a seal issue, or something else that is causing the crankcase to either over pressurize or just defeat the seal under normal working parameters.
 

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Discussion Starter · #6 ·
How hard are you driving the car? Almost any engine will leak a bit out of the rear main if you're stomping on it. Drive easy for a week and check to see if it's leaking.
Average to slightly spirited driving 90% of the time. The only driving I would consider hard was a half-day autocross driving course I did a few months back but no hard launches or clutch dumping. Either way as Duece said, a rear main shouldn't fail under normal operation. I drove my Mazdaspeed pretty hard on a regular basis for 3 years and never had a rear main seal issue, in fact I don't think I've had a rear main go bad on any car I've ever owned. If Focus ST's are this delicate then **** 'em I'll get something else, probably not another Ford.

Not entirely sure, normally accidents or front end trauma seem to cause leakages, but if you don't have such a history then idk.

As stated above though, any kind of flaw on the crank would eat up the seal. In a perfect world the Ford tech would have thoroughly inspected both the crank end, and the sealing surface in the block. Which I highly doubt, given today's trends in auto repair.

I wonder if @PA_LE has any luck on his second rear main...



Huh? This is a statement I have never heard anything about, never experienced firsthand, and am highly skeptical of in its entirety.

A motor in good health should not be leaking oil from the rear main seal at all regardless of how you drive it. It's a seal, not a "oh lets weep a bit of oil when the crankcase pressure increases".

In all my years, and all my cars, I have never seen this to be true. I drive the **** out of all my cars. Wrench on all of them, and have never seen this come to fruition.

If driving your car spirited is causing your rear main seal to leak, then your motor has issues. Either PVC issues, blow by issues, a seal issue, or something else that is causing the crankcase to either over pressurize or just defeat the seal under normal working parameters.
I'm inclined to agree here, there is on reason a healthy motor should be leaking from the rear main. The seal has a job of keeping oil in, if it's failing to do that then something is abnormal. Have yet to call the dealership as I haven't had time to go without my car for a week while they sort this **** out. Soon hopefully..
 

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Discussion Starter · #8 ·
Update:

Car is at the dealership. Hadn't heard anything for 4 days so I called to check. They are suggesting that my Roush intake may be why my rear main seal is leaking. Service advisor states they are checking with Ford service to see. Have a sneaking suspicion they are about to refuse to cover it.
 

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Update:

Car is at the dealership. Hadn't heard anything for 4 days so I called to check. They are suggesting that my Roush intake may be why my rear main seal is leaking. Service advisor states they are checking with Ford service to see. Have a sneaking suspicion they are about to refuse to cover it.
This is compete bull****. A bigger tube is not going to damage any component, it has nothing to do with a rear seal breaking. Only thing a tube does is allow for smother air flow, The crank case builds pressure because of pressure from the turbo. We have a small crank case plate on the front of the engine block( this is the PVC system). Not the best set up but its there.
 

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Discussion Starter · #11 ·
Final update with added bonus:

The rear main seal was repaired under warranty. According to the dealership there was an update to the service manual that changed the installation proceedure. There was some issue with the installation that would cause the rear main seal to fail again. They promised this time it's fixed and won't leak again (not soon anyway)

Bonus:

My dash cam caught a technician repeatedly revving my car to redline and talking to another tech about trying to "get it to shoot flames". Shortly after they noticed I had a dash cam and guy 1 asked guy 2 "have you driven it hard yet?" This video will be provided to the service manager shortly.

Edit: I should mention, I didn't have the dash cam last year and they put 75 miles on my car in the time they had it which seemed suspicious for just doing a rear main seal. That made me decide to review all of the videos after picking the car up tonight.
 

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75 miles wtf, and also wtf to the rest of that post
 

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Well here I am with my #2 Rear main seal leaking....Special process? WTF, i'm irate. 10 miles on the new one and it failed. I didn't remove the oil pan prior to install.
Oh geez man.
 

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LMAO i KNOOOOOW! :haha: I just found a stripped bolt in the linkage plate (above the tranny) probably due to vibrations....poopy
Stripped bolt from vibrations? That's a tough one to see happening. All of my bolts would be stripped by now, lmao!

Looks like you are pulling it all apart again, you better inspect the crap out of the sealing surface, and the crank for imperfections.

Are you wrenching by hand, or using air/electric tools?

Wrenching while fatigued or stressed?

Idk wtf is going on meng, but it doesn't seem to be working well these days.
 

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Stripped bolt from vibrations? That's a tough one to see happening. All of my bolts would be stripped by now, lmao!

Looks like you are pulling it all apart again, you better inspect the crap out of the sealing surface, and the crank for imperfections.

Are you wrenching by hand, or using air/electric tools?

Wrenching while fatigued or stressed?

Idk wtf is going on meng, but it doesn't seem to be working well these days.
Your right, i'm having a hard time with this build...I'm wrenching by battery, then torquing by hand to spec.
pulling it all apart again....I don't want to...but i'll just be wasting money on oil.
I'm tired of this car to be honest
 

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Your right, i'm having a hard time with this build...I'm wrenching by battery, then torquing by hand to spec.
pulling it all apart again....I don't want to...but i'll just be wasting money on oil.
I'm tired of this car to be honest

I hear yah, it always blows when you spend so much time and more/same problems arise.

Battery gun most likely stripped that bolt. Being the shade tree mechanic I am, I pretty much stick with hand tools for everything on the ST. I use a battery impact for removing some bolts, everything is installed by hand. Except that V-band clamp, I impact the **** outta that, lol

We need portals, so I can zip over with some beer and give you a hand tearing her apart/putting her back together.

Hang in there Bro, she's a sweet ride, just has a few kinks.
 

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I hear yah, it always blows when you spend so much time and more/same problems arise.

Battery gun most likely stripped that bolt. Being the shade tree mechanic I am, I pretty much stick with hand tools for everything on the ST. I use a battery impact for removing some bolts, everything is installed by hand. Except that V-band clamp, I impact the **** outta that, lol

We need portals, so I can zip over with some beer and give you a hand tearing her apart/putting her back together.

Hang in there Bro, she's a sweet ride, just has a few kinks.
Thanks @Duece McCracken, the thought is much appreciated. I'll stop using the hand impact for these little job's; the housing is def. stripped i'll have to go to a shop to have them re-thread since i'm not exp. in re-threading myself.
I'll be looking for a Transmission shop to re-install the rear main seal, Ford wants to charge my soul to put a new one in.
 
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