No luck w/ptfe seals?

So I’ve replaced 5 crank seals within 8,000 miles trying to get the front of my crank to not leak oil, albeit a very small leak, it bothers the hell out of me, my rear main is leaking too...just haven’t had the motivation to tackle that at all.

I’m a mechanic by trade, a foreman at the Subaru dealership I work at, I know how to install seals correctly and with care.

I’m starting to blame it on the type of seal Cummins uses for these applications, a PTFE (teflon) type seal, with no retaining spring. I contacted a custom seal manufacturer to help me develop a spring type seal...they will most likely make me buy a lot of them.

Anybody else ever have atrocious luck with the teflon seals that our trucks use??

Thanks for any and all help/comments

Have any end play on the crank?

Not sure for the CR but the 12V has a speedy sleeve for when the crank has a groove, if that’s what is possibly going on?

Also too much crank case pressure will push seals out quick.

Does this thread need to be a group buy thread or troubleshooting thread?

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I have a few rear main seals that are rubber with a spring in them for tension.
I bought them on Ebay, from a guy back east a few years back, who apparently had a large quantity made because he was tired of the PTFE ones leaking.

IIRC, he was an engineer for Chrysler back when.

Mark.

I sleeved mine and bought new Oversized CNH seals for the sleeves and I have no leaks so far from the mains.

biggy238 said:

Does this thread need to be a group buy thread or troubleshooting thread?

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Click to expand...

Was just thinking out loud I guess, dont intend to start any kind of group buy

smokinVE said:

Have any end play on the crank?

Not sure for the CR but the 12V has a speedy sleeve for when the crank has a groove, if that’s what is possibly going on?

Also too much crank case pressure will push seals out quick.

Click to expand...

The front of my crank has been sleeved, the rear is soon to be once I tear out the trans again.

Engine was rebuilt about 9k miles ago, so I have not checked endplay recently, but I will right now. The engine is a heavy breather, meaning it has a little bit more blow by than average (I broke it in like a *****). I am also utilizing a stock 6.7 valve cover and ccv filter, using the turbo inlet as a source of vacuum.

I’ve tried a gutted ccv filter and fresh crank seal at the same time, with no changes, besides oil residue in my charge air piping.

Mark Nixon said:

I have a few rear main seals that are rubber with a spring in them for tension.
I bought them on Ebay, from a guy back east a few years back, who apparently had a large quantity made because he was tired of the PTFE ones leaking.

IIRC, he was an engineer for Chrysler back when.

Mark.

Click to expand...

Interesting....pm sent

Pics of the seals I mentioned.

Mark.

Poulina said:

Was just thinking out loud I guess, dont intend to start any kind of group buy

Click to expand...

I was just trying to steer it away from a "this is what you did wrong" thread. Nothing against you

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