6 Serious BMW N46 Engine Problems (From Owners)

The N46 motor by BMW is 1 of those universally hated engines. Wondering why? Well, for one, nan second-hand, precocious mileage owners usually cashed retired their wallets connected each nan repairs and secondly, nan N46 replaced immoderate of nan legendary 4 cylinder engines (M44 for example) that were featured successful nan E46 BMW 3 Series.

Here are nan astir communal BMW N46 motor problems:

• Timing concatenation and tensioner failures
• Various and superior lipid leaks
• Cam and crankshaft sensor failure
• VANOS solenoid problems
• Valvetronic and VVT centrifugal failures

To find retired much astir these problems, I contacted 3 past owners of BMW E90s pinch this motor and I did thorough investigation online. Here is much specifications astir each problem I listed above.

BMW N46 Engine Specs & Applications

Before we get into each nan concerns surrounding this engine, it’s important that you cognize nan basics of nan motor building and nan cars that characteristic it.

The N46 motor has a displacement of 1.8 aliases 2.0 litres, depending connected nan type (N46B18 is nan 1.8 and nan N46B20 is nan 2.0). Both variants characteristic 4 cylinders successful a consecutive 4 configuration.

This motor uses nonstop substance injection and BMW’s Valvetronic valve timing technology, which makes judge that nan valves are adjusted continously.

All variants of nan motor are people aspirated, meaning you don’t request to interest astir immoderate turbocharger relates problems. Talking astir turbo’s, let’s screen nan powerfulness and torque figures next.

1. N46B18:
   • Power: Approximately 115hp / 85 kW
   • Torque: Approximately 175 Nm astatine 3750 rpm
2. N46B20:
   • Power Output: Approximately 127 to 170 hp (depending connected nan variant)
   • Torque: Approximately 180 to 210 Nm

The N46 motor tin beryllium recovered successful nan pursuing BMW models:

• 1 Series – E81/E82/E87/E88 pinch nan 120i badge made from 2007 to 2011
• 3 Series – E90/E91/E92/E93 pinch nan 320i badge made from 2007 to 2013
• 5 Series – E60 pinch nan 520i badge made from 2007 to 2010
• X1 Series – E84 pinch nan xDrive 18i badge made from 2009 to 2015
• X3 Series – E83 pinch nan X30 2.0i badge made from 2007 to 2010

Common BMW N46 Engine Problems

I listed each nan communal motor problems for you astatine nan beginning, but I’m judge you want to cognize more. Here’s much item for each of nan problems.

Timing concatenation and tensioner failure

They opportunity nan pome doesn’t autumn for nan character and successful this lawsuit it’s not bully news. Just for illustration nan N47 engine I wrote astir recently, nan N46 motor besides suffers from timing concatenation problems.

This is astir evident successful early exemplary years of nan N46 and nan main problem is timing concatenation stretching. This occured chiefly arsenic a consequence of timing concatenation tensioner failures, but nan consequence could beryllium catastrophic if near ignored.

The main denotation of this rumor is nan emblematic cold motor rattling, nan ignition of nan cheque motor informing ray and reduced motor performance.

Like I said before, if near untreated, nan timing concatenation could skip up and origin catastophic motor damage. The repairs for this rumor are acold from inexpensive and owed to nan outrage amongst nan owners.

This lead to BMW ackonwleding these timing concatenation issues successful immoderate of their models equipped pinch nan N46 engine, and successful definite cases, they person extended nan warranty aliases offered assistance pinch repair costs for affected vehicles.

Sensitive to motor lipid type

If you’re buying a BMW pinch this engine, make judge that done it’s life it received regular replacements of afloat synthetic BMW approved oils.

A batch of owners study nan value of only pouring successful afloat synthetic motor lipid that is recommended by BMW. Failing to do truthful tin exaggerate and accelerated way immoderate of nan problems connected this list.

If you conscionable bought a N46 powered BMW, make sure, that from now connected you only move successful afloat synthetic motor oil.

Valvetronic centrifugal and crankshaft sensor failures

A communal problem reported connected nan N46 motor is nan nonaccomplishment of nan Valvetronic motor. Once this centrifugal fails, nan motor whitethorn commencement showing signs of each kinds of problems, including:

• Hard aliases no-start occurances
• Rough idling
• Power loss
• Reduced substance economy
• Engine informing ray illumination

The Valvetronic, together pinch nan VANOS strategy is designed to optimize motor capacity by adjusting nan timing of nan opening and closing of nan engine’s intake and exhaust valves.

On nan different hand, a grounded crankshaft sensor is besides communal connected nan N46 motor and it whitethorn origin nan aforesaid issues. That is understandable, since nan crankshaft sensor is responsible for monitoring nan position and velocity of nan crankshaft and is important for motor management, ignition timing, and substance injection.

Cam sensor failure

Long cranking, stalling astatine debased speeds, motor informing light. All of these symptoms bespeak a grounded camshaft position sensor. This is simply a common, but easy to hole rumor connected this engine.

High lipid depletion and galore lipid leaks

I decided to group each of these lipid leaks successful a azygous “problem” because there’s excessively galore communal lipid leaks to database 1 by one. Let’s dive in!

Valve stem seal lipid leaks

This is nan astir communal culprit down nan precocious lipid depletion phenomena pinch this engine. If you do a speedy Google hunt for “N46 and valve stem lipid leak”, you’ll spot a full number of DIY guides and moreover owners printing their ain 3D parts trying to lick and forestall this issue.

The astir communal denotation of this lipid leak is incredibly precocious lipid depletion and achromatic aliases bluish fume coming retired from nan exhaust pipe.

Oil select & lipid cooler lodging seal lipid leaks

This is 1 of nan astir communal lipid leak areas connected this motor and 1 that you’ll look eventually. Replacing some gaskets is simply a alternatively elemental DIY job, truthful this 1 is not a woody breaker.

Oil sump gasket leaks

The lipid sump gasket is bound to commencement leaking astatine 1 constituent successful clip connected this engine. Again, if you’re into DIY repairs, this should not beryllium excessively hard. Make judge you cheque your bottommost motor protection for lipid leaks regularly arsenic this lipid leak tin lead to important nonaccomplishment of motor oil.

Valve screen gasket lipid leaks

This should beryllium connected your to-check-list erstwhile it comes to uncovering lipid leaks connected nan N46 engine.

Brake vacuum pump O-ring and main seal lipid leak

This lipid leak location is emblematic for some nan N42 motor and nan N46 engine. Owners picture nan main show communicative motion of this lipid leak is nan smell of burned lipid erstwhile braking and aft braking. You tin besides spot hints of achromatic fume coming from beneath nan hood arsenic nan lipid burns disconnected nan basking manifold.

When you break, nan lipid leaks retired of nan vacuum pump connected nan O-ring and nan main seal of nan vacuum pump and it drips connected basking motor components.

This is communal rumor truthful successful lawsuit it hasn’t been return attraction disconnected yet, expect to do nan occupation sometime successful your ownership. Luckily, it’s not a large nor costly repair truthful you should beryllium conscionable fine.

If you want to tackle this repair connected your own, I propose you travel this amazing guide.

Dirty aliases faulty VANOS solenoids

VANOS solenoids connected each BMW models are responsible for controling nan travel of lipid to nan VANOS unit, which regulates nan timing adjustments of nan camshafts.

If you’ve ever owned a BMW than you cognize VANOS problems are bound to arise. Two of nan communal problems are soiled aliases faulty VANOS solenoids. Once these solenoids became soiled aliases faulty, they suffer their expertise to power lipid flow.

This leads to timing issues, which results successful mediocre idling, mediocre and unpredicatable motor capacity and moreover nan ignition of nan motor informing light.

At nan aforesaid time, besides communal is nan deterioration of nan VANOS seals. As these seals fail, they leak lipid and nan nonaccomplishment of unit successful nan VANOS strategy tin lead to unsmooth idling, reduced power, and mediocre motor performance, particularly astatine little RPMs.

FAQ

Is BMW N46 motor reliable?

No, BMW’s N46 motor is decidedly not BMWs astir reliable petrol engine. One of nan biggest issues we spot pinch this motor is nan timing concatenation and tensioner problems which tin lead to costly repairs aliases catastrophic motor damage.

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