[FD7683]

Hey guys,

I'm looking to getting a E90 328i possibly next year as a "fun car." It will be a manual. Although i'm a college student, i can repair the car no issues as i will have a backup fund, and a Honda Civic as the real daily.

The 335i N55 is really tempting given the dual exhaust, and the nice sound it gives. Although the chance of me buying an N55 powered 335i is very low, i'm curious to see if the N55 Rod Bearing failure is really that serious of a problem.

How long do N55's usually last before they get rod knock? just curious. Also, how's reliability in the aspect of the N55 engine.

[E92.Dom]

It's not serious at all. It can happen but it's extremely rare. As long as the car is taken care of and the oil is changed you'll be fine. 335i is 10x the car the 328 is if you like it buy it and don't look back.

[9krpmrx8]

It's a non issue and honestly you could not (try it) find five actually documented cases of the rod bearings being the failure point. Sure people have had their engines fail, but every engine you can think of has a premature failure rate. And there are so many variables as to what the cause actually was. But most of the people reporting failures like some here for example, who blame the engine, were on multi owner cars with little to no maintenance history throwing 25psi +, etc, etc on who knows what tune. Of all the stories I have seen, I can only think of two that were original owner, non modified cars that were well maintained and they just got new engines under warranty, no inspection or verification as to why they failed. The ones that were reported failures at the dealers (big reddit post about it), were typically after some work and such so who knows wtf happened at the dealer. The N55 was produced in much higher numbers and was in in many more models than the N54 was. For example in 2012, BMW sold 1.8 million vehicles. Most dealer reported failures ( a few guys here and there with basically no details) are guesses at best because the dealers are not even allowed to crack open the engines to find out how they failed. So even if you could find 50 documented failures, they would be statistically insignificant. And N54's fail at a decent rate (search and you will see) and you don't hear anyone saying the N54 has a rod bearing problem, and the rod bearings are used on later model N55's, S55, etc. and those don't have a problem. The N55 was in the following vehicles over the past 10+ years.
N55B30M0

2009–2017 F10/F11/F07 535i
2010-2013 E90/E91/E92/E93 335i
2010-2013 E82/E88 135i
2010–2017 F25 X3 xDrive35i
2011-2013 E70 X5 xDrive 35i
2011–2015 F30/F31 335i
2011–2014 E71 X6 xDrive 35i
2012–2015 E84 X1 xDrive35i
2013–2016 F32/F33/F36 435i
2014–2018 F15 X5 xDrive 35i
2014–2019 F16 X6 xDrive35i
2014–2016 F26 X4 xDrive 35i

N55B30

2011–2018 F06/F12/F13 640i[13]
2012–2013 E82/E88 135is[14]
2012–2015 F20/F21 M135i[15][16]
2012–2015 F01 740i/Li

N55B30

2013–2016 F22/F23 M235i
2015–2016 F20/F21 M135i LCI

N55HP

2013–2015 F30 ActiveHybrid 3

N55B30T0

2015–2018 F26 X4 M40i — 265 kW (355 bhp)
2016–2018 F87 M2 — 272 kW (365 bhp)

[oVeRdOsE.]

Even if its not an issue, I coded the auto stop/start to ''last known position'' .

Basically, the stop feature is always disable when I start the car. It will give a huge break to the rod bearing on heavy city drive.

[Biginboca]

All the reports of N55 RB issues I have come across were related to the oil filter housing gasket repair process. Apparently bmw has revised the procedure for that to now include a priming of the engine by running the starter without fuel delivery before the first cold start after the OFH Gasket repair.

OP I recommend you do some googling on N55 Failure after Oil Filter Housing Gasket Repair and see what comes up. Then you can determine if its an issue for you.

Personally, I’m very risk averse and that’s why I purchased a N52 car. But knowing what I do the N55 is within my risk tolerance and if I wanted a turbo car I would not think twice about buying a clean one with maintenance records. I would just be cautious about the start up procedures after an OFH Gasket repair.

[Tunafish]

The ofhg is one of the big things that happened to this engine and others as i read.. The priming procedure and complete replacement of the ofh is now a procedure bmw uses... But there is reports of oil starvation under heavy track use, mainly in the cornering, psi dropping down to 10 then back up, i believe that individual did spin a bearing eventually..

I personally think that the long oil changing intervals that bmw went to helped premature bearing wear (i have no actual evidence of this). The DI engine which dilutes the oil and running a turbo causing added oil thermal breakdown is not a recipe for success.. That is one thing i would look for in a n55, good oil change history and not going by bmw intervals, i like to see 5k oil changes with full synthetic and 3 with convention..

[solo118]

Originally Posted by FD7683

Hey guys,

I'm looking to getting a E90 328i possibly next year as a "fun car." It will be a manual. Although i'm a college student, i can repair the car no issues as i will have a backup fund, and a Honda Civic as the real daily.

The 335i N55 is really tempting given the dual exhaust, and the nice sounding exhaust. Although the chance of me buying an N55 powered 335i is very low, i'm curious to see if the N55 Rod Bearing failure is really that serious of a problem.

How long do N55's usually last before they get rod knock? just curious. Also, how's reliability in the aspect of the N55 engine.

I would say it should be very low on your list of concerns with the N55. Thankfully the engine is decently reliable, when maintained properly.

The failures I saw was premature, or where the OFHG was changed improperly.

[solo118]

Originally Posted by oVeRdOsE.

Even if its not an issue, I coded the auto stop/start to ''last known position'' .

Basically, the stop feature is always disable when I start the car. It will give a huge break to the rod bearing on heavy city drive.

Can you explain this? I did not know the e9x even had auto start/stop.

[9krpmrx8]

Originally Posted by solo118

Can you explain this? I did not know the e9x even had auto start/stop.

The E9X does not have this feature.

[9krpmrx8]

Definitely follow the service bulletin if you are opening the oiling system. I have also attached an internal dealer memo that a tech shared with me.

[Leucosticte]

Originally Posted by 9krpmrx8

The E9X does not have this feature.

It did in Europe, you can retrofit it pretty easily if you have the switch.

[FD7683]

Thanks for the replies! given the record history of rod bearings from BMW, i might just settle for the N52 powered car. I'll just throw in the 3-Stage Intake Manifold to give it a bit more kick like the 330i.

I would hate to get rod knock on a BMW. Also, i'm not sure how much the 335i will cost to insure as a young driver lmao.

[E92William]

N52 with 3 stage and 3.91 final drive is a fun car just it lacks the immediate torque of a turbo engine.

The n55 seems like it has an electronically controlled oil pump which might have something to do with these bearing issues after you empty the filter housing for the gasket change, still though it doesn't make sense to me how this happens because you'd drain it too to change the filter.

[kart23]

Originally Posted by E92William

The n55 seems like it has an electronically controlled oil pump which might have something to do with these bearing issues after you empty the filter housing for the gasket change, still though it doesn't make sense to me how this happens because you'd drain it too to change the filter.

Are you sure it's electronically controlled? I'm pretty sure it's mechanically driven off the crankshaft, like literally every other car.

https://www.newtis.info/tisv2/a/en/e...e-oil/F7gMhV54

[E92William]

That's what I've been told I haven't really checked at all tbh. But it wouldn't have surprised me that even if it's crank driven that it would have some kind of actuator that would adjust its operation, not like the n55 didn't eventually go to an electric waste gate for the turbo too. If it's not a pump issue then I'm at a loss as to why these engines spin bearings after draining the oil filter housing once when others don't

[MightyMouseTech]

The N55 oil pump is mechanically driven, but the pressure is electronically controlled. Pretty much all of the engines that seize do so during cold snaps in the winter. Must have something to do with the variable pump pressure system getting stuck. Much more common on the X3 and X5 N55's. I believe it is also why this happens on the N63. It is significantly more frequent with that motor.

[hi rpm]

Originally Posted by MightyMouseTech

The N55 oil pump is mechanically driven, but the pressure is electronically controlled. Pretty much all of the engines that seize do so during cold snaps in the winter. Must have something to do with the variable pump pressure system getting stuck. Much more common on the X3 and X5 N55's. I believe it is also why this happens on the N63. It is significantly more frequent with that motor.

I read hundreds of posts in a dozen threads hoping to find something to prevent my N55 rod bearings failing without much luck, so I'll just hope. But one thing I thought of that I didn't see mentioned was the accessory oil cooler with thermostat valve that doesn't open until the engine is hot. I wonder if some failures are caused by cold oil rushing into "warmed up" engines, the tight clearanced bearings prevent flow into them, and that's that. In winter it can be several minutes before oil temp hits even 160F, so you could be gunning it on the highway when the cooler valve opens. Just an idea.