N55 oil transmission cooler/heat exchanger leaking?

c_trak · Yesterday, 09:53 AM

Hi.

I have a 2011 BMW 335 (N55) and noticed this slow leak coming from the oil transmission cooler/heat exchanger. Does anyone know if this can be taken apart so I can replace the gasket/seal? If so, can someone please share the part #.

Thank you for any of your input.

StradaRedlands · Yesterday, 09:39 PM

Yes, 100% a DIY job.
Here's the seal: https://www.fcpeuro.com/products/bmw...ng-11428637820

You'll want to replace the OFHG seal whilst there: https://www.fcpeuro.com/products/bmw...et-70-37157-00

And right below it the Mickey Mouse flange: https://www.fcpeuro.com/products/bmw...e-rein-chc0609

Also, if oil has been leaking on the accessory belt, replace it ASAP as well. Check tensioner and pulleys while doing that, you may want to R&R at the same time.

Sort of fun/rewarding jobs. Do it right now though, leaking oil onto the belt can lead to catastrophic engine failure. That's bad.

N55 engines should be primed for oil after you take the OFH off, so research that procedure as well.

Yes, it never ends...

Yesterday, 09:53 AM	#1
c_trak Registered 0 Rep 1 Posts Drives: 2011 BMW 335i Join Date: Sep 2024 Location: Chino CA iTrader: (0)	N55 oil transmission cooler/heat exchanger leaking? Hi. I have a 2011 BMW 335 (N55) and noticed this slow leak coming from the oil transmission cooler/heat exchanger. Does anyone know if this can be taken apart so I can replace the gasket/seal? If so, can someone please share the part #. Thank you for any of your input. Attached Images
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Yesterday, 09:39 PM	#2
StradaRedlands Brigadier General 6105 Rep 3,649 Posts Drives: 2006 BMW 330i MT Join Date: Dec 2021 Location: SoCal iTrader: (2) Garage List 2006 BMW 330i [8.25] 2009 BMW 328i Touri ... [8.00] 2013 BMW X5 35i [7.80] 2011 BMW 528i [8.70] 2006 Mazda3 [5.50]	Yes, 100% a DIY job. Here's the seal: https://www.fcpeuro.com/products/bmw...ng-11428637820 You'll want to replace the OFHG seal whilst there: https://www.fcpeuro.com/products/bmw...et-70-37157-00 And right below it the Mickey Mouse flange: https://www.fcpeuro.com/products/bmw...e-rein-chc0609 Also, if oil has been leaking on the accessory belt, replace it ASAP as well. Check tensioner and pulleys while doing that, you may want to R&R at the same time. Sort of fun/rewarding jobs. Do it right now though, leaking oil onto the belt can lead to catastrophic engine failure. That's bad. N55 engines should be primed for oil after you take the OFH off, so research that procedure as well. Yes, it never ends...
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