So, you’re looking at a BMW with the N54 engine but you’ve heard that this may not be the most reliable engine in the BMW line up. Hi guys and welcome back to the SimpleCarGuy channel. Today, we will talk about the history, common problems, issues solved over time, how reliable the engine is 15 years later as well as my personal experience.
The reason I’m making this video is because I owned a BMW 335i e92 with the N54 engine for about 4 years from 2013 to 2017 and I wanted to catch myself up and see how the reliability has been since I sold my car! This is also part of a small series where I’m looking into engines I own or have owned and creating reliability reports like this video. BMW N55 video is coming up soon, so subscribe to see it and hit that like button to support the channel!
BMW N54 is one of the best straight six engines every made by BMW for a few very good reasons. Not only was it the first mass produced BMW turbocharged engine, but it also came with a forged crankshaft and connecting rods leaving HUGE tuning potential. Even though the stock engine made 302 HP, it’s not very difficult to get it up to 500hp or even much, much more. So, how can this reward winning engine [show which awards] have issues? Well, while the actual engine has had some amazing innovations and engineering, a lot of the accessories and auxiliary components are not as well designed. Of course, when looking at a used BMW with the N54 engine, it doesn’t help that a lot of them have been tuned and driven hard! [HUGE tuning potential and people love it, but also abuse it] So, let’s take a look at some common problems you can expect on a BMW N54 engine
Even though there were 3 different power figures for this engine, mechanically its basically the same engine. I’ll go over the difference between the standard N54B30 and the N54B30TO that was used in the 1 Series M Coupe and Z4 sDrive35is.
Let’s start with the stand N54B30 engine. The biggest and most common issue that has haunted the BMW N54 engine since the start is the HPFP going bad and preventing the engine from starting, sometimes stuttering, misfiring or running well in general. It was such a big issue that BMW has extended the warranty on these to 10 years and 120,000 miles in the United States. The good part here is that most of the cars have already had the pump replaced with a revised version while under warranty.
- Water Pump
Another big common problem on the N54 engine is the electric water pump that uses some plastic parts. These fail unexpectedly and usually at the worst time! I’ve had 2 OEM water pumps fail on me when I had the car. I got the yellow triangle saying that the engine is running hot and within 2 minutes a red triangle with a message saying to drive moderately and to shut off the engine as it has overheating. Unlike the HPFP, there is no extended warranty or anything like that and unfortunately, the pump is very difficult to get to. I paid around a $1000 each time it failed in Chicago. The pump is about $400 and labor is at least that much again.
- Fuel Injectors leaking, Ignition Coils
These engines also suffer from leaky injectors. BMW N54 uses direct injection and these must be very precise for the engine to run correctly. Unfortunately, when they start leaking which can cause many different problems including hard to start engine once warmed up, rough idle and misfires as well as terrible fuel economy among other issues. Of course, some of these symptoms can be caused by a bad spark plug or coil and I would definitely recommend replacing those before touching the injectors as each injector is about $250.
- Turbochargers/wastegate rattle – people upgrade them for more power
Next issue that’s common on many BMW engines including the N54 is the wastegate rattle. Early on, this isn’t a huge issue as it mostly just makes a rattling noise on start up, it gets worse and worse over time. Eventually, the wastegate flapper starts leaking boost and causing performance issues. If not taken care of at this stage, the ECU will try to compensate for the lack of boost potentially overheating and destroying the turbocharger and maybe even the engine if metal gets into the intake. In addition to the wastegate rattle issue, turbo seals can fail and cause smoke out of the exhaust. These issues are more common on tuned or hard driven cars. Small piece of advice here is to not punch it hard until the engine is fully warmed up and to let the engine idle for a little while after driving hard before shutting off the car. [explain why let it idle][Aftermarket upgrades are very popular.]
- Leaks become more common once getting closer to 100k
If you have watched my BMW N20 engine video [link it], this will sound very familiar. There are a few oil leaks to watch out for and the most common one is the valve cover oil leak. Usually, the plastic valve cover will crack and start leaking. Sometimes the gasket goes bad as well and the entire cover should be replaced. It’s important to get this done quickly as it would be leaking on the exhaust manifold, turbos and the O2 sensors. The oil filter housing gasket is also prone to leaking and should be replaced ASAP as it will leak oil onto the serpentine belt and can cause all kinds of problems. Oil pan leaks are less common, but possible.
The next common issue on these engines is the chargepipe that cracks over time. BMW used a plastic pipe between the intercooler and the intake manifold which runs under boost a lot of times and of course becomes brittle and eventually fails. I’ve had this fail on my N55 [n55] engine as it uses the same design and replaced it with an aftermarket one that works much better. This is an easy and inexpensive fix to a common problem.
- Minor items:
There are of course many other little issues with these engines that you may need to take care of over time, such as the starters going bad out of no where [link N20 video] or VANOS solenoids causing loss of power, engine hesitation, rough idle and decreased fuel economy. I have actually made a video on how to test and clean these if you’re interested and they are a decently simple DIY. Carbon build up is another issue that shows up on many lists, but that’s common on most direct injected engine and not BMW or this engine specific.
As I mentioned earlier, N54B30TO was the more powerful version of the N54 engine making 335HP, but this was achieved mostly by adding a performance power kit tune and some supporting cooling hardware. [list: upgraded fan, radiator hoses, secondary radiator, oil cooler]. So, the engine itself was the same but with just a little more boost. This also means that all problems we have discussed so far are also present on this version of the engine as well.
Best and Worst Years:
Now 15 years after it has been released and after so many problems, should you even be looking at buying one? Luckily, this engine has had somewhat of a cult following lately and is becoming sought after in the tuner’s world. This also means that most people are trying to preserve it and maintain it properly. Additionally, issues like the HPFP and injectors have been resolved from the dealer and mostly done under warranty. Most other issues have been figured out in the aftermarket world with the upgraded turbochargers to get rid of the wastergate rattle and metal chargepipes to prevent boost leaks. One word of advice, avoid getting an already tuned engine if you plan on dailying your ride. [notes on why not]
A quick note on my personal experience with the engine. Over the period of 4 years and about 55,000 miles, I had to replace the spark plugs, ignition coils and 2 water pumps and nothing else. In every video I’ve made about the BMW engines I’ve owned, people tell me I just got lucky and that may be true, but it doesn’t hurt to properly take care of these engines as well.
In conclusion, remember that this is an aging BMW motor that was packed with top-of-the-line technology and most likely driven hard by the last owners, so be ready to spend a little bit of money on maintaining it properly. It’s a wonderful, powerful and still one of the more reliable engines made by BMW with lots of aftermarket support and capability to produce tremendous power! Check out my BMW N20 and N63 engine reliability reports and stay tunes for the N55 video as well. Thank you so much for watching and I’ll see you in the next one!