Engine Oil & Oil Leak Question

[325_driver 422]

2.5l n51

125,000km on the clock

1. Oil Leak

Smells of oil burning at idle from time to time, and the level is definitely going down over time - what are some usual places to check

From the receipts i've seen they have recently had the head off from a mechanical insurance claim when they did the water pump and thermostat, and the rocker cover looks pretty well sealed, no major oil seeping down

can't see any obvious leaks round the sump

Whats are some usual culprits?

 

2. Oil grades

Are there any threads on here regarding oil grades for e90's n51/52 b25

I have been searching on here and can't find much, maybe i'm just bad at searching

Fully Synthetic 0w30, 0w40, 5w30?

Will 15w40 or 20w50 kill it? (Thinking of topping it up with oil i already have a bit before doing an oil change later, and obviously finding this damn oil leak)

I'm not thrashing it, and don't give it death in the morning, just wondering what everyone's experiences are.

 

Thanks so much!

 

Edited July 8, 2019 by 325_driver

[qube 3570]

oil filter housing gasket if it hasnt been done, rocker cover also common issue.

its never a good idea to mix oils. fully synthetic 5w-30 or 5w-40 is good.

even for top up's i'd try keep it the same.

[325_driver 422]

30 minutes ago, qube said:

oil filter housing gasket if it hasnt been done, rocker cover also common issue.

its never a good idea to mix oils. fully synthetic 5w-30 or 5w-40 is good.

even for top up's i'd try keep it the same.

do n51's drink a bit of oil? Done about 3,000km since i bought it, might have gone down 1lt 

I read somewhere that the accepted limit for BMW's is 1lt per 1000km 

So maybe a little leak somewhere + thirsty for oil?

I honestly can't find anything oil leak wise, it looks pretty clean since the shop work done on it before i bought it

[Driftit 2069]

Do N51's have a PCV valve?  A PCV with a worn out diaphragm (common in cold weather) will cause an oil smell and consume oil over time.

They are vacuum controlled.  So another cause is vacuum leaks.  Probably the most common BMW issue.

I would check for Vacuum leaks first.  Then have a look at the PCV valve.

There should be plenty of guides on youtube.

 

Checking for vacuum leaks isn't always easy.  The fastest way to do this is running a smoke test.  Where the smoke leaks out is where your leak is.  The gear to do this isn't usually owned by the home mechanic though.

Edited July 8, 2019 by Driftit

[325_driver 422]

5 minutes ago, Driftit said:

Do N51's have a PCV valve?  A PCV with a worn out diaphragm (common in cold weather) will cause an oil smell and consume oil over time.

They are vacuum controlled.  So another cause is vacuum leaks.  Probably the most common BMW issue.

I would check for Vacuum leaks first.  Then have a look at the PCV valve.

There should be plenty of guides on youtube.

 

Checking for vacuum leaks isn't always easy.  The fastest way to do this is running a smoke test.  Where the smoke leaks out is where your leak is.  The gear to do this isn't usually owned by the home mechanic though.

i might end up purchasing one of them, vaccum leaks seem to be a life story for me, this car seems to have a maze of vaccum lines, hidden behind tough to reach places

the person that purchased my 330ci emailed me saying he found and fixed a vaccum leak and he got about 30% better fuel efficiency and runs smooth as anything from it after

[Driftit 2069]

5 minutes ago, 325_driver said:

i might end up purchasing one of them, vaccum leaks seem to be a life story for me, this car seems to have a maze of vaccum lines, hidden behind tough to reach places

the person that purchased my 330ci emailed me saying he found and fixed a vaccum leak and he got about 30% better fuel efficiency and runs smooth as anything from it after

Yup I had to do the same thing to my 325ci in the US.  I found someone had removed one of the blanking caps on the back of the motor to stop the stuffed PCV from working.  Shitty yank mechanic trick to sell a car.  I plugged it back in and within seconds had flooded a large underground carpark (in the bloody Embassy) with white smoke.

Replaced the PCV and all the problems were solved.  That was a stuffed PCV though.  After that she stopped eating oil and became as fuel efficient as they get.  Engine light for running lean stopped coming on too.

Should mention changing out the PCV is a prick.  Usually under the intake manifold.  BMW quoted me $1800USD to do it.  I did it myself for whatever the PCV was worth.  $50 odd on Amazon with overnight delivery.

Edited July 8, 2019 by Driftit

[325_driver 422]

1 minute ago, Driftit said:

Yup I had to do the same thing to my 325ci in the US.  I found someone had removed one of the blanking caps on the back of the motor to stop the stuffed PCV from working.  Shitty yank mechanic trick to sell a car.  I plugged it back in and within seconds had flooded a large underground carpark (in the bloody Embassy) with white smoke.

Replaced the PCV and all the problems were solved.  That was a stuffed PCV though.  After that she stopped eating oil and became as fuel efficient as they get.  Engine light for running lean stopped coming on too.

hmm i did have an engine check light come on, and i'm waiting on the OBD tool to arrive, i wonder if they are linked

Fuel efficiency seems to be pretty nice though, 9.5l/100 round town, 7.5l/100 on open road, which to me is living the dream for a 325i

It's just this oil thing that's a bit confusing, 

i'm not sure if the electronic oil dip stick is a little in-accurate either

missing the good old days where i had an oil dip stick

[325_driver 422]

8 minutes ago, Driftit said:

Yup I had to do the same thing to my 325ci in the US.  I found someone had removed one of the blanking caps on the back of the motor to stop the stuffed PCV from working.  Shitty yank mechanic trick to sell a car.  I plugged it back in and within seconds had flooded a large underground carpark (in the bloody Embassy) with white smoke.

Replaced the PCV and all the problems were solved.  That was a stuffed PCV though.  After that she stopped eating oil and became as fuel efficient as they get.  Engine light for running lean stopped coming on too.

Since it didn't come with an owners manual, i've been reading online, and found someone else's,

according to the electronic dip stick reading on the dash, the difference between the minimum line and the maximum line is 1l approximately?

When I picked up the car it was just below the maximum line, 3,000km later it is now slightly under half, towards the minimum line, so maybe gone through so maybe at that rate 1lt of oil per 6,000km?

Do you think this is within the common amount of oil these engine's burn through, as every where i look it seems to be that these motors drink a bit of oil.

[Jacko 2152]

N51s are US spec emissions choked versions (SULEV). Your car should be an N52B25A

 

N52s, of the "silver top" variety run an external CCV system, which is a known failure point. Essentially its an oil/air seperator under the intake manifold which dumps oil back to the sump, and the fumes to the intake. When they die, the oil goes to the intake. Pretty common reason for excessive oil consumption.

Oil leaks - 

Rocker Gasket - It'll pool over exhaust manifold and stink. They also break bolts (ali, torque to yeild, and often just snap because they can). If its broken a bolt, since the engine work, it'll leak like a sieve. Lift the engine cover and check they all still have heads. 

Sump Gasket - Common leak, left rear corner, will pool on bottom of bellhousing where the o2 sensor plugs are, gets hot as gets flicked on exhausts and stinks

Valvetronic motor gasket - Look under the engine cover, will pool out on top of rocker cover and down the plug tubes etc

Oil Cooler/Filter fitting - Common leak, makes a mess down front of engine. Put ya hand under neath the oil cooler and you'll know if its leaking

Edited July 8, 2019 by Jacko

[Driftit 2069]

Ah yeah wrong name.  I meant CCV valve the entire time.  sh*t of a thing.

[Jacko 2152]

Oil grades -

BMW LL Rated 5w30.

Castrol make some, super cheap have it on special often. 

Penrite HPR5 5w40+10 also meets the LL spec, and the 5w30 spec (and comes in a 6l bottle, handy for the 6.5l sump)

 

 

Oil in them is pretty critical IMHO, the LL spec includes all the additives for the magnesium block, and the vanos system is not gonna be happy running weird viscosity, never mind all the bearing tolerances (or the cam ledges). The only really lunched N52 ive heard of was a guy running 0W50 superbike oil in one... because racecar? 

Edited July 8, 2019 by Jacko

[Gaz 1058]

13 minutes ago, 325_driver said:

do n51's drink a bit of oil? Done about 3,000km since i bought it, might have gone down 1lt 

I read somewhere that the accepted limit for BMW's is 1lt per 1000km 

So maybe a little leak somewhere + thirsty for oil?

I honestly can't find anything oil leak wise, it looks pretty clean since the shop work done on it before i bought it

Not overally common for them to drink oil, more so with the 4/8 cylinders. Map your usage over time to get a handle on how much it is using. Eg - do an oil change and once the add 1 litre warning comes on, note how many KM's you have done. Repeat a couple of times to get an average. Correct oil can also make a difference.

That limit is typically for M cars, if you are doing that then typically have valve stem seal issues but again, dont see that too often

[325_driver 422]

43 minutes ago, Jacko said:

Oil grades -

BMW LL Rated 5w30.

Castrol make some, super cheap have it on special often. 

Penrite HPR5 5w40+10 also meets the LL spec, and the 5w30 spec (and comes in a 6l bottle, handy for the 6.5l sump)

https://www.supercheapauto.co.nz/p/valvoline-valvoline-synpower-engine-oil---5w-40-5-litre/100341.html

Basically anything fully synthetic 5w30 / 5w40 ?

[Jacko 2152]

Nope, LL01 5w30.

 

https://www.supercheapauto.co.nz/p/castrol-castrol-edge-engine-oil---5w-30-a3-b4-5-litre/299206.html#q=Castrol%2B5w30&lang=en_NZ

 

https://www.supercheapauto.co.nz/p/penrite-penrite-hpr-5-engine-oil---5w-40-5-litre/14911.html#q=HPR+5&sz=1&start=12 

[325_driver 422]

1 minute ago, Jacko said:

Nope, LL01 5w30.

 

https://www.supercheapauto.co.nz/p/castrol-castrol-edge-engine-oil---5w-30-a3-b4-5-litre/299206.html#q=Castrol%2B5w30&lang=en_NZ

 

https://www.supercheapauto.co.nz/p/penrite-penrite-hpr-5-engine-oil---5w-40-5-litre/14911.html#q=HPR+5&sz=1&start=12 

Thanks, you the man

Really not in the mood to damage an engine from poor oil choice

i might have got away with it in the m54b30 because it was high km's, but not wanting to risk it on this

[325_driver 422]

9 minutes ago, Jacko said:

Nope, LL01 5w30.

 

https://www.supercheapauto.co.nz/p/castrol-castrol-edge-engine-oil---5w-30-a3-b4-5-litre/299206.html#q=Castrol%2B5w30&lang=en_NZ

 

https://www.supercheapauto.co.nz/p/penrite-penrite-hpr-5-engine-oil---5w-40-5-litre/14911.html#q=HPR+5&sz=1&start=12 

Just trying to figure out how i find out if it's LL-01 approved (in future when i'm looking at oils), what am i looking for on the page

i.e. is this one ll-01 

https://www.supercheapauto.co.nz/p/penrite-penrite-full-synthetic-engine-oil---5w-30-4-litre/518962.html#q=penrite&prefn1=adArticleType&prefv1=Full+Synthetic+Engine+Oil|Full+Synthetic+Oil

[Jacko 2152]

37 minutes ago, 325_driver said:

Just trying to figure out how i find out if it's LL-01 approved (in future when i'm looking at oils), what am i looking for on the page

i.e. is this one ll-01 

https://www.supercheapauto.co.nz/p/penrite-penrite-full-synthetic-engine-oil---5w-30-4-litre/518962.html#q=penrite&prefn1=adArticleType&prefv1=Full+Synthetic+Engine+Oil|Full+Synthetic+Oil

Check out the penrite site, the supercheap listing doesnt have all the spec. I have about 210,000km N52B30 kms ticked up on the Castrol now (between two cars), last oil change switched to HPR 5, as saw it also met the spec.. and is arguably technically superior... 

[325_driver 422]

11 minutes ago, Jacko said:

Check out the penrite site, the supercheap listing doesnt have all the spec. I have about 210,000km N52B30 kms ticked up on the Castrol now (between two cars), last oil change switched to HPR 5, as saw it also met the spec.. and is arguably technically superior... 

Sweet, HPR 5 looks like the go, just looking for an oil to stick to, unless some 50% off pops up on another suitable brand lol then i'll bulk buy

[325_driver 422]

For reference, for those looking in the future

this oil here meets the grade requirements in the owners manual also meets the LL-01 requirement - and is 50% off at the moment at super cheap auto.

https://www.supercheapauto.co.nz/p/castrol-castrol-edge-engine-oil---5w-40-5-litre/299205.html?cgid=catalogue-onsale

https://www.castrol.com/en_au/australia/car-engine-oil/engine-oil-brands/castrol-edge/edge-product-page.html

[Olaf 3309]

I changed from Castrol Edge 0w40 to Penrite HPR in two vehicles, found they ran smoother, reduced oil consumption, and leaked less.  HPR5 meets BMW LL01.  It’s cheaper than Castrol Edge; bought on sale in 20 litre packs it works out closer to $7.50/litre.

[Olaf 3309]

Also interesting to note that BMW in USA have changed from 5w30 to 5w40.  Regardless of what’s in the owners manual.

[325_driver 422]

36 minutes ago, Olaf said:

I changed from Castrol Edge 0w40 to Penrite HPR in two vehicles, found they ran smoother, reduced oil consumption, and leaked less.  HPR5 meets BMW LL01.  It’s cheaper than Castrol Edge; bought on sale in 20 litre packs it works out closer to $7.50/litre.

yeah i've bought enough for the next bit + next oil change, but i'll be keeping an eye out for discounts on penrite hpr 5, that's the oil i would prefer.

might give the CCV a crack, it does have a small stream of white smoke in the start up which i thought initially was just humidity, but combine that with the very subtle variation in the start up idle, and smell of oil at idle, i'm leaning towards thinking the CCV (or PCV what ever it is) is old

[325_driver 422]

21 hours ago, Driftit said:

I did it myself for whatever the PCV was worth.  $50 odd on Amazon with overnight delivery.

Do you just buy the cover?

https://www.amazon.com/Cover-Engine-Valve-128i-328i/dp/B077SNPPPQ/ref=sr_1_4?keywords=n52+pcv&qid=1562639215&s=gateway&sr=8-4

[Driftit 2069]

Mine was slightly different but that's the but that fails. 

[Jacko 2152]

6 hours ago, 325_driver said:

Do you just buy the cover?

https://www.amazon.com/Cover-Engine-Valve-128i-328i/dp/B077SNPPPQ/ref=sr_1_4?keywords=n52+pcv&qid=1562639215&s=gateway&sr=8-4

Thats not it. This is the one on my 330, yours will be similar - https://www.fcpeuro.com/products/bmw-crankcase-breather-kit-11617531423kt1 check on realoem.com.

Its pretty annoying job, grab some aircon disconnect tools (cheap) to disconnect the sump connection, its a total pig without them. 

You can change them without changing the lines, however odds are good you will break a line removing them (they get really brittle) -

 

This is what mine did with a dead CCV, it was coating all the manifolds sensors with oil, and making the fuel trims go all up the pish. Reseting the DME adaptations fixed it temporarily, post CCV it uses the same as the 130 (maybe 100ml between oil changes)

 

Edited July 9, 2019 by Jacko