It is probably safe to update this thread. It is hard to say when I started hearing unsavory noises from my engine, but for more than 15,000km, this motor has been making "low oil pressure" type noises. No knocking, but it just sounded a bit rattly, was susceptible to lifter tick and would make dangerous sounding noises above 5000rpm... another clue was the red oil pressure light that would take 3 or 4 sec to switch off on startup while the motor made a weird didgeridoo type noise. To help me sleep at night, I compartmentalized this as typical old engine noises...
Ignoring all that, I needed to tackle my powersteering system which had developed a catastrophic leak from the steering rack. I would use this opportunity to throw in a known good used pump (mine was noisy and had a lot of play on the shaft) and steering rack (my old one had already been rebuilt less than 100,000km ago) and make up a new powersteering line that looked to be knocking on deaths door.
My "good used" pump was of a different design and did not fit (why BMW, why?) so I replaced that with another used pump which turned out to be properly fu@ked. I finally swapped that with another used pump. I really should be less of a jew with this car. Anyway, with all this running around, I had some spare time to drop the sump to investigate the possibility of a loose oil pump nut. The nut was fine, but the oil pickup most assuredly, was not! Shit.
That was properly blocked I'd say 🤦♂️ Looks like tissue somehow found its way into my engine...no idea how or when. Perhaps stupidly, I decided to ignore the one or two magnetic flakes in the oil filter and send it. The car had been off the road now for 2 months and I needed it for a trip to the coast. After all, the oil pump looked fine...how bad could it be?
I buttoned the car back up to be greeted with a silky smooth and quiet M54! It felt more responsive at lower rpm with no more oil pressure and didgeridoo noises at start up...amazing what a bit of oil pressure can do...
Alas, it could not be such a simple fix...There was a distinct knocking noise which was getting worryingly louder...the wolf was at the door, and it was impatient. At this point I deserted the E46 and focused my time on the E39 which was to take us to the coast where it found new and interesting ways to test my resolve. Anyway, that misadventure is covered elsewhere on this forum.
After an unexpectedly expensive holiday, I prepared myself for a bottom end rebuild while debating if I should pull the head off the motor to replace the oil burning piston rings. I was using about a litre of oil per 1500km. Debate over I would say...
2 spun bearings and yes, that really is a bearing cap in 4 pieces...
Crank took a beating as well
Sitting with a dead E46 and E39, I was "stuck" dailying the Z4 (tough, I know) and needed this car back on the road quickly, so after much searching and many bad/dodgy engines, I found what seemed like a good "low mileage" engine from a X3 at a frankly exorbitant cost.
"Low mileage"
Compression seemed consistently poor...but perhaps understandable for a motor that had been standing for a while.
No signs of bore damage and the oil pump and pickup looked mint, so I figured I would send it
Out with the old
Swear and shout a lot
Do a spot of cleaning
Notice anything missing? I didnt...
Hmmm...I should probably change the clutch "while Im at it"... As Richard Hammond wisely said: You need to keep draining your bank account. You cannot give it the chance to recover and gain strength as it will start defending itself. To this end, I replaced the engine mounts, stabilizer links, oil filter housing gasket, rear main seal and valve cover gaskets.
At this point, while access was easy, I placed an order for a set of Viper exhaust manifolds - surely my original cats must be blocked and not doing much for the environment any more. Viper, being the useless company they are, quite simply never fulfilled my order and I needed to get the motor in and tested before the warranty expired, so I installed the "new" engine with the old manifolds.
But wait, BMW left me one last easter egg...You see, the replacement engine came from a X3, and ofcourse the X3 would have a different coolant return hose and ofcourse the hose would break off in the block while removing it and ofcourse the O-rings will pinch when you try reinstall it and ofcourse you will discover this once the engine is back in...
Swear and shout some more because removing the inlet manifold to get to the offending hose is now a 6 hour knuckle busting affair.
Thankfully, the motor sounds good. I did an oil flush, replaced all filters and fluids and buttoned the car up for a test drive only to be greeted with a propshaft-like vibration on deceleration...hmmm
after engaging my finest chin scratching, I realized the "new" engine, being from an automatic car, did not have a pilot bearing which supported the gearbox input shaft! Blithering idiot! 😡 Car immidiately went back on the lift to remove the gearbox and clutch. AGAIN. FFS! At this point, the obvious thing to do was order an exhaust manifold from Powerpipes since the car was on the lift and the gearbox was out.
Proceed to swear and shout at the manifold which turned out to be an absolute ballache to remove. Would have been a 5min job with the motor out, thanks Viper!
See something strange? These were sold to me as "equal length" bolt in manifolds. All one can do is laugh...
Yup, that is akin to throwing a sausage down a hallway...and ironically, that is a Viper manifold 🤷♂️ Should flow better than the contorted stock manifolds.
After a hilariously noisy drive to work, I dropped the car off a powerpipes to make up the missing exhaust piece
Then proceed to give the motor an italian tune, it deserves it. The Viper manifold has made the exhaust quite raspy, I am not sure I like it, but at least the volume has not increased and the nice deep tone of the M54 remains.
After 4 months of dailying the Z4, the E46 feels like a wallowy SUV! I really missed this car tho...now to put some hopefully trouble free miles on it 🤞
