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BMW N55 Common Problems and Repair Costs
The N55 repairs owners report most are oil leaks (oil filter housing gasket, valve cover gasket, oil pan gasket, rear main seal), the plastic charge pipe, cooling parts such as the electric water pump and expansion tank, and wear items like injectors and spark plugs.
Last updated · By BimmerQuote (how we build guides) · Costs on this page come from the linked repair pages, each citing its sources.
What this list is, and is not
The list below comes from owner price reports that BimmerQuote has cited. It tells you which N55 repairs owners have been quoted or paid for, not how often they fail. The engine page is BMW N55 engine.
Our repair data names the N55 in the 335i, 435i, 535i, 135i, M235i and M2, plus the X5 35i. If you are comparing it with the newer inline-six, the BMW B58 vs N55: Which Engine Is More Reliable? guide sets the two side by side.
Oil leaks
Oil leaks lead the N55 list. The oil filter housing gasket drips oil onto the serpentine belt and is the classic one (Oil Filter Housing Gasket (OFHG)). Several commenters stress priming the oil system before starting the engine after this job. The valve cover can warp or crack, and then the whole cover is replaced (Valve Cover / Valve Cover Gasket). The oil pan gasket usually means lowering the subframe, and xDrive cars cost more because the front axle is in the way (Oil Pan Gasket).
Oil from the filter housing, pan or valve cover often collects at the same place as a rear main seal leak, so diagnosis matters before approving the transmission-out job (Rear Main Seal).
A loud pop followed by a sudden loss of boost, limp mode or a hissing noise under acceleration is the charge pipe. Most commenters recommend an aluminum aftermarket pipe so it does not crack again. See N55 Charge Pipe.
Injectors show as a misfire on one cylinder that follows the injector, with rough idle and a fuel smell. Ask whether a quote is for one injector or all six, and note that EU5 injectors need injector codes entered in the DME. See N55 Fuel Injectors. The in-tank pump is a separate cause of power loss (Low Pressure Fuel Pump (In-Tank)).
The electric water pump and thermostat are normally replaced together (Electric Water Pump + Thermostat). On F30 cars the plastic expansion tank is the repeat offender; one N55 owner went through three tanks in eight years, each failing at the bonded seam (F30 Coolant Expansion Tank & Coolant Lines).
According to the repairs owners have priced: oil leaks (oil filter housing gasket, valve cover gasket, oil pan gasket, rear main seal), the electric water pump and thermostat, the plastic expansion tank and the plastic charge pipe.
How much does the N55 oil filter housing gasket cost?
Oil Filter Housing Gasket (OFHG) on a BMW with the N54/N55/N52 engine typically costs $208–$1,950 at an independent shop, $500–$2,257 at a BMW dealer, or $32–$100 in parts DIY, based on 27 real owner-reported prices.
How much does an N55 charge pipe cost to replace?
N55 Charge Pipe on a BMW with the N55/N20 engine typically costs $500–$1,400 at an independent shop, $600–$1,900 at a BMW dealer, or $250–$446 in parts DIY, based on 9 real owner-reported prices.
Do N55 ignition coils need replacing with the plugs?
Several commenters say coils are not a wear item and only need replacing if they cause misfires. Spark Plugs & Ignition Coils (N55) on a BMW with the N55 engine typically costs $250–$1,200 at an independent shop, $650–$1,500 at a BMW dealer, or $150–$480 in parts DIY, based on 8 real owner-reported prices.
Where this comes from
Every cost on this page is pulled from these repair pages, which list the price, the forum or shop source and the details for each report. This guide adds no prices of its own.
