E90 oil leak diagnosis

ec362 · 05-16-2018, 05:56 PM

Hi
First post. My 3 series '06 E90 320i has 71000 on the clock. I've recently had to top up the 1l oil much more frequently- like twice in two months. So far, so e90. But no leak on the drive, no white/blue smoke etc... Trying to work out where the leak is coming from, going to have a proper look next week but wondered if these pictures give any definite ideas from the usual culprits. Not the best pics but worth a try before getting into UV etc. I've done a bit of basic car DIY over the years- my own oil changes, parts replacements etc- but I really want to commit to learning more around the engine and have a go within reason, this site looks really useful to help if it's a more accessible gasket to replace. (fingers crossed)
Thanks

Phil325i · 05-17-2018, 11:35 AM

Oil filter housing gasket or valve cover gasket are the most likely culprits.

ec362 · 05-17-2018, 01:07 PM

Thanks. Do the pictures indicate those things specifically, or are they just the most likely causes in general of the E90 leaks?

labrador · 05-20-2018, 04:31 PM

Those are common E90 leaks. With the valve cover gasket you need to change the Vanos motor gasket and eccentric shaft sensor grommet.

Search them up on RM European.

nickpitcher · 05-10-2021, 08:35 PM

Did you ever find the leak? Looks like one or both of the vanos solenoids are leaking. Cheap and easy fix.

e91Owner · 05-12-2021, 01:13 AM

Some of the replies seem more geared to the common US engines. We do not have the N43 here, so your question may be better answered in the international forums.

The valve cover is similar in that it has a rubber gasket that is probably equally prone to leaking; however the oil filter housing is entirely different and may or may not be a problem. Another poster commented on the valvetronic motor seal, however, I do not believe your engine has valvetronic, only vanos. The two vanos solenoids are covered with oil in your photos. They do have hard rubbber seals, so that could be a cause of a leak, but it could also just be leaking down off of the valve cover.

One beautiful thing the N5x engines don't have that yours does is a separate PCV that is not integrated into the valve cover. If yours is blown, it would be an easy replacement and often solves many top engine oil leaks on BMWs. Good luck!

lowrydr310 · 05-13-2021, 06:53 PM

Quote:

Originally Posted by ec362

Thanks. Do the pictures indicate those things specifically, or are they just the most likely causes in general of the E90 leaks?

Both. The photos indicate a possible valve cover and oil filter housing gasket leak, and they're both common failures on the E90.

05-16-2018, 05:56 PM	#1
ec362 Registered 1 Rep 3 Posts Drives: E90 320i Join Date: May 2018 Location: UK iTrader: (0)	E90 oil leak diagnosis Hi First post. My 3 series '06 E90 320i has 71000 on the clock. I've recently had to top up the 1l oil much more frequently- like twice in two months. So far, so e90. But no leak on the drive, no white/blue smoke etc... Trying to work out where the leak is coming from, going to have a proper look next week but wondered if these pictures give any definite ideas from the usual culprits. Not the best pics but worth a try before getting into UV etc. I've done a bit of basic car DIY over the years- my own oil changes, parts replacements etc- but I really want to commit to learning more around the engine and have a go within reason, this site looks really useful to help if it's a more accessible gasket to replace. (fingers crossed) Thanks Attached Images
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05-17-2018, 11:35 AM	#2
Phil325i Brigadier General 639 Rep 3,215 Posts Drives: E92 325i MSport Coupe Join Date: Apr 2012 Location: UK South East iTrader: (1) Garage List 2009 BMW 325i Coupe [6.00]	Oil filter housing gasket or valve cover gasket are the most likely culprits. __________________ E92 pre-LCI 325i - Ohlins R&T; H&R spacers; M3 strut brace; Swift thrust sheets; 3 x chassis braces; diff brace; N53 V-brace; 034 subframe inserts; BMS clutch stop; BMS CDV; RE g/box mounts; Delrin shift bushes; Saikoumichi OCC; Cyba scoops; BMW Perf Exhaust; HEL s/steel brake hoses; M3 rear spoiler; Recaro Sportster CSs; M3 white dash LEDs; LED Angels; LED side repeaters; BMW Perf black grille; CSL reps; SSDD carbon diffuser; Monster Wrap black roof/clear front
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05-17-2018, 01:07 PM	#3
ec362 Registered 1 Rep 3 Posts Drives: E90 320i Join Date: May 2018 Location: UK iTrader: (0)	Thanks. Do the pictures indicate those things specifically, or are they just the most likely causes in general of the E90 leaks?
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05-20-2018, 04:31 PM	#4
labrador Second Lieutenant 65 Rep 218 Posts Drives: E90 Join Date: Mar 2018 Location: California iTrader: (0)	Those are common E90 leaks. With the valve cover gasket you need to change the Vanos motor gasket and eccentric shaft sensor grommet. Search them up on RM European.
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05-10-2021, 08:35 PM	#5
nickpitcher Registered 0 Rep 1 Posts Drives: BMW e91 320i Join Date: May 2021 Location: Auckland, New Zealand iTrader: (0)	Did you ever find the leak? Looks like one or both of the vanos solenoids are leaking. Cheap and easy fix.
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05-12-2021, 01:13 AM	#6
e91Owner e91Owner 433 Rep 1,140 Posts Drives: 2011 e91 Join Date: Mar 2018 Location: Out of the Office iTrader: (0)	Some of the replies seem more geared to the common US engines. We do not have the N43 here, so your question may be better answered in the international forums. The valve cover is similar in that it has a rubber gasket that is probably equally prone to leaking; however the oil filter housing is entirely different and may or may not be a problem. Another poster commented on the valvetronic motor seal, however, I do not believe your engine has valvetronic, only vanos. The two vanos solenoids are covered with oil in your photos. They do have hard rubbber seals, so that could be a cause of a leak, but it could also just be leaking down off of the valve cover. One beautiful thing the N5x engines don't have that yours does is a separate PCV that is not integrated into the valve cover. If yours is blown, it would be an easy replacement and often solves many top engine oil leaks on BMWs. Good luck!
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