[DOCTOR.Y]

Hi all,

I am thinking to upgrade my 325i to 335i for more power and fun. Reliability is quite important to me, have done some research about 335i`s reliability. Known that N54 causes more issues than N55, so I would like to pick up one with N55. To me tune potential is not as important as reliability, so should be a N55 motor with no more than 50000km for sure. Just have some uncertainties about N55, any advice is greatly appreciated

1. Has BMW really worked out a solution on HPFP issue on N55? Is the new pump (943) approved to work with problem free?

2. What about the lifespan of the turbo in real life? 80000Km? Never owned a turbo BMW so no idea at all.

3. Some complains DCT easily got issue, I am not clear with this and didn't find too many information. Any one would like to add his/her opinion?

4. I noticed 335i exhasut pipe is much more dirty than 320i, 325i, 330d (these cars I have been driven for some time). Simply a layer of black stuff coated inside the pipe. These propose another question: carbon residue. Is carbon residue a series problems with this direct injection engine? If so, anyway to clean and how often should do?

5. any other issues?

That`s pretty much all I am concern. Any comments are greatly appreciated, thanks guys.

[Nitrousbird]

N55 isn't any more reliable than an N54, excluding maybe wastegate rattle:
- Same HPFP
- Similar injectors
- Same need for walnut blasting
- It's a BMW, it will find places to leak oil
- Same water pump failures
- Same coil packs

N54 is still being produced and used by BMW. N55 is not really any more reliable - owners of them typically state this to justify either a newer vehicle purchase or justify their less mod friendly motor.

[grizz311]

Its not as easy as n55 vs n54... For instance n55 vs early model n54 = n55 is the more reliable engine. Compare to 2011 n54 from 335is i would say around the same reliabilty. They had the time to iron out some kinks in the n54 motor.

[Bamaben]

The n55 head and valve cover design does a better job of not recirculating oil back thru intake and therefore has less carbon buildup in intake reducing frequency of walnut blasting.

[DOCTOR.Y]

Originally Posted by Nitrousbird

N55 isn't any more reliable than an N54, excluding maybe wastegate rattle:
- Same HPFP
- Similar injectors
- Same need for walnut blasting
- It's a BMW, it will find places to leak oil
- Same water pump failures
- Same coil packs

N54 is still being produced and used by BMW. N55 is not really any more reliable - owners of them typically state this to justify either a newer vehicle purchase or justify their less mod friendly motor.

Thanks mate

[DOCTOR.Y]

Originally Posted by grizz311

Its not as easy as n55 vs n54... For instance n55 vs early model n54 = n55 is the more reliable engine. Compare to 2011 n54 from 335is i would say around the same reliabilty. They had the time to iron out some kinks in the n54 motor.

Yeah I didn`t look at N54, simply looked at N55 made after 2011 thanks for advice mate

[DOCTOR.Y]

Originally Posted by Bamaben

The n55 head and valve cover design does a better job of not recirculating oil back thru intake and therefore has less carbon buildup in intake reducing frequency of walnut blasting.

So how often should do walnut blasting ?

[sirdaft1]

Originally Posted by grizz311

Its not as easy as n55 vs n54... For instance n55 vs early model n54 = n55 is the more reliable engine. Compare to 2011 n54 from 335is i would say around the same reliabilty. They had the time to iron out some kinks in the n54 motor.

But even that point isn't true. Most (if not all) early model N54's have had new HPFP's, turbos, etc installed due to manufacturer recalls, making them no less reliable than later model N54's or N55's.

[DOCTOR.Y]

Originally Posted by sirdaft1

But even that point isn't true. Most (if not all) early model N54's have had new HPFP's, turbos, etc installed due to manufacturer recalls, making them no less reliable than later model N54's or N55's.

I am amazed the way N55 manages its temperature after switching off the engine for a long while. I always park my car in garage which has a relatively warm condition. My last N52 had its engine oil temp below 70 when I started up the car next morning and goes up slowly; in comparison, today when I started up the N55 same time in the morning, oil temp reads 72-73°C and go quickly to 100. I believe this is good to reduce engine parts wear at cold start.

I have driven a F30 LCI for some days and found B48 has an excellent thermo management system, but didn`t expect that N55 also has such a quick warm up.

[robthewrench]

Originally Posted by Eric_Y

1. Has BMW really worked out a solution on HPFP issue on N55? Is the new pump (943) approved to work with problem free?

2. What about the lifespan of the turbo in real life? 80000Km? Never owned a turbo BMW so no idea at all.

3. Some complains DCT easily got issue, I am not clear with this and didn't find too many information. Any one would like to add his/her opinion?

4. I noticed 335i exhasut pipe is much more dirty than 320i, 325i, 330d (these cars I have been driven for some time). Simply a layer of black stuff coated inside the pipe. These propose another question: carbon residue. Is carbon residue a series problems with this direct injection engine? If so, anyway to clean and how often should do?

:

I'm biased having an N55, and this wasn't by chance. I want to avoid some of the N54 issues, real or fiction. I agree with an earlier poster that you should absolutely avoid early 07-09 N54s.

The HPFP is not completely fixed and some N55 owners have had their replaces. The software fix in later model years for the N54 and N55 to run the low pressure pump before the high pressure pump has reduced the failure rate.

N55 has a much better oil separator design and does not have the intake build up problems of the N54.

I thought the N55 had a different injection system. You also don't hear about N55 owners having to change their injectors out (at high $) like early N54 owners. I could be wrong about this.

A turbo is typically good for about 100K miles, depending on conditions. This applies to all turbos in my opinion. Having previously owned a WRX, even that turbo wore out at 100K miles.

[JustDriveIt]

Yikes, I wouldn't do it unless it was under a CPO warranty. If reliability is what you're looking for, this car is going to cause way more headache than enjoyment for you. Of course it's always the luck of the draw, but with so many issues these cars have it's going to cause you problems at some point.

[Shock6822]

If peace of mind is super important to you, maybe CPO or even another party's warranty is worth researching.

[mike@x-ph.com]

Reliability is important to you and you are considering N54/N55?

These are the best cars to own for fun driving and absolute cheap mod potential but they are not reliable thats for sure

Surprisingly the engine is very reliable, problems occur with the supporting components

[Fundguy1]

Originally Posted by Nitrousbird

N55 isn't any more reliable than an N54, excluding maybe wastegate rattle:
- Same HPFP
- Similar injectors
- Same need for walnut blasting
- It's a BMW, it will find places to leak oil
- Same water pump failures
- Same coil packs

N54 is still being produced and used by BMW. N55 is not really any more reliable - owners of them typically state this to justify either a newer vehicle purchase or justify their less mod friendly motor.

+1. Same issues. It's a falacy that the n55 is more reliable. The parts in question were redesigned and now are the replacements on the n54 and since they're bound to have failed by now they probably have the new parts on the n54s. Find one you like, either motor, and go. As to the mileage, these parts and turbos have different milage they go at. Turbos should last a long time. Really I'd say it should be more about styling, mod potential, and price. Also know the lci n55 bodies can't fit as big a rear tire.

[CharlieBear]

In bold...Then don't buy a 335i, seriously. Previous 335i owner.

Originally Posted by Eric_Y

Hi all,

I am thinking to upgrade my 325i to 335i for more power and fun. Reliability is quite important to me, have done some research about 335i`s reliability. Known that N54 causes more issues than N55, so I would like to pick up one with N55. To me tune potential is not as important as reliability, so should be a N55 motor with no more than 50000km for sure. Just have some uncertainties about N55, any advice is greatly appreciated

1. Has BMW really worked out a solution on HPFP issue on N55? Is the new pump (943) approved to work with problem free?

2. What about the lifespan of the turbo in real life? 80000Km? Never owned a turbo BMW so no idea at all.

3. Some complains DCT easily got issue, I am not clear with this and didn't find too many information. Any one would like to add his/her opinion?

4. I noticed 335i exhasut pipe is much more dirty than 320i, 325i, 330d (these cars I have been driven for some time). Simply a layer of black stuff coated inside the pipe. These propose another question: carbon residue. Is carbon residue a series problems with this direct injection engine? If so, anyway to clean and how often should do?

5. any other issues?

That`s pretty much all I am concern. Any comments are greatly appreciated, thanks guys.

[DOCTOR.Y]

reliability is important, but not means it can`t go wrong. I just don`t want a car to break down all the time. Certain well known issues like HPFP etc I can accept if they happens not quite often.

[mike@x-ph.com]

Originally Posted by Eric_Y

reliability is important, but not means it can`t go wrong. I just don`t want a car to break down all the time. Certain well known issues like HPFP etc I can accept if they happens not quite often.

If you are good with chaing fuel pumps, water pumps every 3 years and turbos every 5 years .. Get the 335 it is well worth it

Othen changes that might be needed radiator, radiator lines, stock charge pipe

Other than fuel pumps, water pumps and turbos the 335 is as reliable as any other BMW

[Delta0311]

Originally Posted by Nitrousbird

N55 isn't any more reliable than an N54, excluding maybe wastegate rattle:
- Same HPFP
- Similar injectors
- Same need for walnut blasting
- It's a BMW, it will find places to leak oil
- Same water pump failures
- Same coil packs

N54 is still being produced and used by BMW. N55 is not really any more reliable - owners of them typically state this to justify either a newer vehicle purchase or justify their less mod friendly motor.

Wrong on injectors. N55 uses Bosh selnoid injectors and not piezo injectors like the N54. Water pump failures and gasket leaks are common to all BMWs. N55 also does not require frequent walnut blasting.

[Jsoboti]

61k miles and just had to have the HPFP replaced. 2011 E92 335i.

[DOCTOR.Y]

Originally Posted by mike@x-ph.com

If you are good with chaing fuel pumps, water pumps every 3 years and turbos every 5 years .. Get the 335 it is well worth it

Othen changes that might be needed radiator, radiator lines, stock charge pipe

Other than fuel pumps, water pumps and turbos the 335 is as reliable as any other BMW

That sounds not too bad to me, thanks for providing such detailed information.

[bimmerboi510]

Hey, I'm in the same step as you, looking for a n54 335i, do your research on this forums regarding the common issues and then take it to a trusted mechanic of YOUR choice, make sure the previous owner isn't someone shady and I think you will be good.

[DOCTOR.Y]

Originally Posted by bimmerboi510

Hey, I'm in the same step as you, looking for a n54 335i, do your research on this forums regarding the common issues and then take it to a trusted mechanic of YOUR choice, make sure the previous owner isn't someone shady and I think you will be good.

Howz your N54 hunting mate? I have found my N55, checked all over, its all good

Just one thing I notice is different from previous 325, the engine speed increases a little bit, say 200 rpm when I turn the steering wheel at stationary. Not sure if this is because the hydraulic power is supplied by the engine.