BMW N47 Engine (N4720, Problems, How To Fix)

BMW N47 Engine Problems – How to Fix Timing Chain Failure!

Introduction

From 2007 to roughly 2014, the BMW N47 was an inline 4-cylinder diesel engine that was used in the BMW 1, 2, 3, and 5 series, as well as the X1 and X3 diesel models.

The N47 engine series is prone to early timing chain failure due to severe timing chain wear. The situation is indicated by a rattling noise coming from the engine’s rear. Failure of the timing chain may necessitate engine replacement or a costly repair. The problem affects all applications and power variations of the engine manufactured between March 1, 2007 and March 1, 2011. The most severely damaged units, which require the most substantial repairs, were manufactured between the dates of 01.03.2007 and 05.01.2009. UPDATE – It appears that a small number of engines made after the recall are having problems.

Timing chain

The timing chain on this engine is sandwiched between the engine and the transmission at the back of the engine. Its replacement is especially difficult because it is located in such an inaccessible location. In most cases, parts installed in such inaccessible locations are intended to survive the life of the engine, but not in this situation. The timing chain in the N47 can fail anywhere from 40 to 100k miles, causing catastrophic engine damage as its components lose synchronization.

Diagnosis – Symptoms of a Failing Timing Chain

The symptoms of a failed timing chain usually appear gradually as the chain becomes longer and more worn. As a result, you’re unlikely to detect a sudden dramatic symptom until the chain is near to break completely. Instead, think about how your vehicle is performing today and how it performed many months ago. Small issues could suggest that the chain is about to fail completely.

Here are some of the signs that your timing chain is failing:

  • Rough idling: Start your automobile and walk away. It’s possible that the timing chain is wearing out if it shakes or vibrates more than usual. Of course, there are other issues that could result in harsh idling, but the issue is always worth investigating because it tends to worsen over time.
  • Strange noises: You might hear your N47 engine rattle, especially when it’s idling, but not only when it’s idling. The issue could be that the timing chain is loose and rattling against anything else if the sound is persistent and rough. 
  • Metal shavings in the oil: Over time, the timing chain will wear down. When it reaches the end of its useful life, it may emit metal shavings. If it does, it will end up in your engine oil, perhaps causing further issues.  However, any worn-out portion of your car can produce metal shavings, so it’s worth looking into before merely replacing the chain.
  • Engine failures: If your BMW would not start, the chai may be damaged and not supplying enough pressure to start the engine. If the chain breaks while you’re driving, it’s possible that the timing chain has broken as well. If this occurs, the pistons may be broken, and the belt problem may cause more damage to your car.
  • Engine misfires: Your N47 engine may misfire before the chain has completely snapped. The cam and the crankshaft are linked by a chain. The chain might cause the vehicle to skip a gear on either the crankshaft or the camshaft if it is overly stretched out. It will become more stressed as a result of this, and it will eventually break.
  • Check engine light is on: Of course, the check engine light could signal a large variety of things have gone wrong with your BMW. However, it’s possible that the timing chain has failed or is soon to fail.

Replacement and Repairs

Because the timing chain is in such an inaccessible location, the mechanic must totally remove the engine from its bay to gain access to it. Taking the engine out is a massive and difficult undertaking in and of itself. Following that, another lengthy disassembly is required to gain access to the chains themselves.

Three timing chains are included in the timing chain replacement kit: one for the oil pump, one for the camshaft, and one for the high-pressure fuel pump. You’ll also need the looking tool kit to keep the crankshaft and camshaft synchronized while you’re working on them. These are the primary tasks that must be completed after removing the engine from the bay in order to replace the timing chains.

To begin, make sure that cylinders 1 and 4 are at top dead center in order to retain the point for synchronizing the points.

With the tools you have, lock your crank shafts at this location.

Remove the camshaft chain tensioner to loosen the chain a little, and loosen the three bolts on the camshaft sprocket.

It will be easier to remove the fuel pump sprocket if the high-pressure fuel pump is turned off.

Remove the flywheel from the crankshaft by removing the bolts that hold it in place.

Remove the starter motor’s bolts to gain access to the oil sump.

By undoing the necessary bolts, you can remove the oil sump.

Remove the timing cover by loosening the nuts that hold it in place. It will take some prying and a few mild taps with the hammer. You can now access all of the chains and sprockets.

By loosening the bolts, you may now remove the oil pump sprocket and the oil pump guides. Remove the oil pump’s chain as well.

Similarly, remove the camshaft sprocket’s guides and tensioner, as well as the sprocket and belt.

After TDC, twist the crankshaft 45 degrees and remove the high-pressure fuel pump tensioner, guides, and sprockets. Take off the belt and the sprockets as well.

The last item is your oil sprayer, which you may remove for replacement if necessary.

Then, in reverse order, install the replacement belts, ensuring that all components are in sync until the conclusion.

Conclusion

This timing chain issue is a design flaw in the engine, and the only method to remedy it is to avoid cars with this N47 engine or, if possible, get rid of it in working order. Because of the emission control equipment put in it, such as the EGR and DPF, this engine also has a lot of issues.

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