The Hidden Oil Leak on the E46 M3! Where it is and how to fix it in Minutes!

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Whats up everyone! If you have an E46 M3, chances are an oil leak is eventually going to develop. It will come from the back of the engine block, and will look like a bad rear main seal which takes some work to fix. However, luckily for you its most likely the Constant pressure valve. A valve that inserts into the block hidden just below the exhaust manifold, specifically header tube #6. Watch the video and learn hot to fix this leak in minutes, so you can stop losing oil and making a mess of the entire underside of your car and driveway!
You'll need a special type of draglink socket to remove the valve. Below are all the parts and specific tools needed for the job! We recommend the kit listed below because its likely the original valve slot(where you insert the bit of the tool/screwdriver) will get some mild damage making it tough to tighten down properly when reinstalling after putting an Oring on. But if your'e confident in not damaging the valve and have a proper tool to remove it, just replacing the O ring will be fine.
Please support Fatboy's Garage by using the links below when its time to purchase parts!
Constant Pressure Valve Repair kit- Includes the socket tool, O ring and Valve
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Constant Pressure Valve Heavy Duty O-ring
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Constant Pressure valve- No O ring included
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BMW Side skirt/ Rocker panel ( Left)
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BMW Side Skirt/rocker panel ( Right)
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Redline Rear DIff 75/90 oil
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Limited Slip Additive
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[@bsouza1675]

ECS Tuning has a Viton seal for the CPV and it is lifetime. I just had this happen to me on my E46 M3. My M3 has only 47K original miles. The stock seal is buna rubber and it shrinks and becomes brittle. Go with the Viton invented by DuPont years ago. Thanks for the vid and I hope this helps.

[@FatboysGarage]

thanks ! thats actually the one we have listed and linked in the description. Perfect choice.

[@TAspeed1]

While using your videos as guide to rebuild my Vanos I replaced that seal at the same time. Mine was barely sipping oil but I figured it was a good preventive maintenance

[@FatboysGarage]

yes! good idea to just do it when you can. Even if its just a little leak it can make a big mess over time. Glad to hear you went and did it and also that you were able to rebuild your Vanos system!

[@BestMotorWerks]

You guys show us very useful things for our m3s e46..thank you

[@FatboysGarage]

Glad to help out man, glad to hear the information is used to keep these cars on the road!

[@BestMotorWerks]

@@FatboysGarage I want to ask you if you will make a video for cracks on the strut tower on the m3 e46, especially on the driver's side...thank you

[@FatboysGarage]

@@BestMotorWerks Yes We will be, We actually have to perform the repair on our track car. So it should be coming soon. Lots of editing underway now. But yes we are definitely doing a video on repairing the strut towers, We also have rear frame reinforcement on the way. Editing is just taking a while.

[@FatboysGarage]

@@BestMotorWerks Yessir. We have some cracks on our strut tower that recently popped up that need repairing. WE will show the repair and reinforcement.

[@chicagovasko]

Seen you at FF had to add you brother. Yeeyee!

[@ninofajardo1288]

Does your clutch pedal buzz/vibrate on high rpm ?

[@8MWm3e4b]

I have a strange feeling that oil is also squitring from there. Everything is dirty from the block back. But, I don’t refill the oil because it’s not missing. This oring is probably the real cause. I would ask, what does this valve regulate at all? Very useful video!

[@FatboysGarage]

Very good chance! The O ring is what fails for sure. We only replaced the valve as well because the slot on the old valve to remove it was damaged and we rather just replace it so if its ever a problem its not an issue to get out. Shouldn't ever happen with the viton seal though. If your valve is good to go, then just do the seal for sure.

[@minuevoluck8197]

Una gran ayuda para cambiar este anillo 👍👋

[@fearthereaper5663]

Hello this can cause oil burning? Thanks a lot

[@FatboysGarage]

yes, if its bad enough you may notice some oil loss and smell the oil from burning on the block and or getting on to exhaust manifolds.

[@tarzan30809]

Thanks! Is this an issue for the e46 in general or only for the M3s? My 2004 325i 210K original miles has a small leak and they think is the oil pan gasket.

[@FatboysGarage]

I cant say that its 100% the issue. IT very well could be though and its a good place to start looking for sure! get it on jacks and start tracing own the leak. If you're finding oil in places that doesn't match an oil pan, its a good chance. I haven't worked on an M54 or id give you more details. Let us know what you find!

[@tarzan30809]

@@FatboysGarage Thanks, that applies to the S54 engines (M3) M54 apparently does not have one

[@macyfrommaxpeedingrods1861]

Hello dude!this is Macy from Maxpeedingrods,do you have any contact?there has a business enquiry for you