Under the hood

Gettin' greasy...

Meanwhile, under the hood, the sound insulation was missing, which is usually pinned to the underside of the lid. It probably got torn at some point, so was just thrown out without replacement. A quick run down to Jolly's Auto Parts fixed that for $15 with one plucked off a wrecked E46 including plastic rivets, and it wiped up very nicely with wax and grease remover to look new. You couldn't even buy the fasteners for that little money.

Then there were new gas struts to hold the hood up, with the original ones barely holding. $55 for a pair from Peninsula BM. And while I was looking at gas struts I also replaced the boot ones to stop that being floppy.

The microfilter housing was badly faded, which happens, and made my eye twitch, so it was given a spray of vinyl coating. The whole cabin air intake asssembly was removed and cleaned while I replaced the spark plugs. Who knows how old they were? They looked original, and were stamped with BMW/NGK, so it was time. The same type of NGK OEM ones went back in.

The existing microfilter? It was new.

Diving into the air box, the existing air filter? It was also new.

Good signs regarding maintenance, so I guess the service books are accurate.

  • Rocker cover off. Engine flush with brake cleaner and two oil changes. It really wasn't that bad in the engine, with not much built-up oil gunk, which is a sign that this engine has received pretty regular oil care. PCV? Oil filter housing gasket and rocker cover gasket $100, plus x cans of brake cleaner for the flush, plus around twelve litres of fully synthetic oil for two changes. I already had plenty of oil filters with gaskets in the shed, having ordered a dozen at one stage to service all the E46s I seem to have owned over the years, in between the recommended BMW oil change intervals that the dealer does. Oil is a car's blood, and keeping it clean keeps an engine that you want to keep for a long time clean and working inside. The oil filter housing gasket wasn't leaking, but I've replace two on previous cars, so did it anyway while I was there. The same for the rocker cover gasket, which seem to be a regular point of oil leaks on E46s (ironically because people usually do the bolts up too tight), and with me taking the cover off anyway it was sensible to change it at that time.
  • The power steering fluid was brown in its reservoir. It should be red. The brown colour will have been coming from the degrading insides of the rubber hoses, which is a sign that they need to be replaced. The reservour with integral filter was also replaced with an original equipment one and new cap beacuse it was leaking, along with the return hose because it was weeping fluid, which is a common thing on E46s. I then flushed the lot. There will probably be another hose or two to replace as well in the near future, but I'll see how the new fluid goes. $215 plus fluid.
  • The coolant in him was water. Just clear water, maybe from a tap. It should be a green coolant-ish anti-rust, anti-freeze, anti-boil BMW colour, so I flushed the cooling system and filled it with a 50:50 mix of BMW supplied fluid and demineralised water. Shit maintenance done the last time something blew or broke in the cooling system, obviously. I hope that was recently, because tap water and engines shouldn't mix.

Cold starts for the engine saw frequent immediate stalls, requiring re-start, and then rough idling, which cleared after a few hundred metres of driving. There wasn't an appreciable fuel smell to indicate unburnt fuel on cold start, so my suspicion was that fuel delivery was the problem. Sure enough, replacing the fuel pump fixed it completely. That also solved some other drivability concerns I'd noticed, and was also a good preventive repair to avoid future side-of-road-it's-fucked surprises.

I replaced one of my sons' original fuel pump on the back of the experience, which is also an E46 and somewhat more travelled, which was having the same issue.

That car is also better now.

Fuel pump under the rear seat cushion.

Then I retrofit an OEM electric cooling fan.

E46 automatic transmission cars came standard with a fan driven by the engine, incorporating a viscous fan clutch that varies the rotational speed based on temperature. This was a really great idea to ensure that a fan is always running at the right speed to cool the radiator, and the engineers at BMW did it because of the increased cooling loads added by fitting an automatic transmission. The manual transmission cars came standard with an electric fan.

Although a really great idea, the really shit part introduced by this always rotating fan is that when the mechanical fan clutch fails on these installs (which seems to be with regularity at typically far higher mileage than Arraow) the fan usually rotates constantly at engine speed, which results in stressed fan blades shooting off in random directions taking out many plastic and rubber components, like coolant reservoir, radiator bits, or serpentine belts, or hoses, or all of these, which gets ... expensive. And usually leaves you stranded on the side of the road.

I recall it happened on my wife's car years back (an E36 manual which had a relatively young 80,000km on the the clock, and this clutched fan arrangement), and the bang was like a gun going off, with plastic bits ricocheting off the road followed by much steam billowing from under the hood. Thankfully this happened a hundred metres from our driveway, so I could park it up and order a shit load of parts.

The other downsides are that the mechanical fan saps power from the engine, makes a truck-like whining sound every time you accelerate, plus doesn't cool very well in bumper-to-bumper traffic, which is often in the city. And it's a bitch to get off the car if needed to repair some engine bits, requiring special tools.

Ugh. Yeah, great idea, but that piece of engineering is gone. I replaced it with the electric job for the win. BMW engineers can go get fucked; it was a great idea that was poorly executed from both a reliability and practicality point of view. The electric fan will now run when it's needed, even if more often than a manual car, and that makes perfect sense to this engineer.

And if the replacement electric fan fails? At least it does so quietly and inexpensively, unless you ignore the temperature gauge warning light. I guess I'll address that surprise in 100,000 more kilometres, which probably won't come.

By the way, if you have a BMW, do not ignore a temperature warning light for more than a minute or so. According to Arraow's service record a previous owner did, which resulted in a blown head gasket and a whisker under AUD$7000 in repairs back in 2014... At least they got a complimentary car wash.