Some steps forward over the past couple of days and a few new jobs for the list: We (I'm doing some of this project with my brother) replaced the leaking vanos casing gasket and whilst in there replaced the vanos piston o-rings and seals (including a major brown trousers moment) and the valve cover gaskets. First though we tackled the apparently dead passenger seat electric adjustment.
The seat was stuck in the fully up and nearly fully back position. The switch did absolutely nothing - totally dead - so we suspected a simple blown fuse when purchasing the car. No such luck. Getting the seat out was the first challenge as the rear rail bolts were obscured by the seat. We disconnected the spindles from the forward/backward motor and inched them forward by using the chucks of two electric screwdrivers. You have to apply quite a lot of force to the spindles to separate them from the motor.
Using two screwdrivers sped things up a bit rather than using the "alternate sides an inch at a time" method. With the seat eventually unbolted from the floor and out we checked the resistance across both motors. Both looked fine at about 4 ohms, so we tried applying a voltage using a starter battery. The forward/back motor worked fine. The up/down motor jolted the mechanism and shorted. The motor was trying to work but the mechanism was jammed.
The height adjustment relies on a rotating bolt/shaft which pushes (height up) and pulls (height down) on a metal housing. Anyone know what this kind of mechanism is called? The end of the shaft is seen on the left in this picture, terminated with a retaining washer. It got jammed in this fully extended position (seat at highest). Anyway, we managed to disconnect the other end (off this picture to the right) and force the housing back onto the bolt/shaft using an appropriately sized spanner to turn it back onto the thread.
We also had to replace the passenger seat adjuster fuse (which was missing from the fuse box - position 5). I guess the original blew, was replaced and blew again so was removed by the garage. Incidentally, the car's BMW centre history says the adjuster switch was broken, requiring a whole new seat at £700, so this felt like a nice DIY victory.
The seat now works perfectly although I'll have to ask passengers, particularly small ones, not to adjust the seat too high for fear of the same happening again. Has anyone had the same issue and found a solution that stops this bolt coming out too far and getting jammed again?
The vanos seal / gasket replacement procedure is well documented elsewhere so I'll just say what went wrong in our case:
I thought I'd read the M54 engine didn't require the viscous coupling fan removal tool. Wrong! Very fortunately we managed to disconnect it using the intertia of the system, a 32mm spanner and a big hammer. The job couldn't have been completed with the fan on as there's not enough space to pull the vanos out from the head bolts.
Brown trousers moment: Despite knowing better, I used a torque wrench near the bottom of its range to tighten the very delicate vanos piston bolts. The inlet piston bolt sheared. As I felt it go I desperately hoped the torx bit had fallen out, but sadly not. Some words were exchanged and I had visions of flat-bedding the zed to a BMW specialist. It was a sorry sight:
That's having taken the vanos unit back off. The white thing in the middle of the timing cog is the sheared end.
Much to our relief, the end of the bolt wasn't actually that tight in the thread. It took my bro about half an hour using a pair of very pointy electronics tweezers to slowly wind the end out. High fives ensued.
We had spare bolts, so thankfully we could carry on. We thought it was going to be so much worse.
Nothing else particularly remarkable happened and I've driven the car 70 miles since with no further visible oil leaks. I can feel no improvement in performance but I guess that's to be expected due to the faulty cam position sensors (see below).
The vanos seal procedure is largely straightforward except the removal of the old seals and o-rings from the vanos pistons. To do this without damaging the pistons took me about an hour and a lot of patience with a very sharp pointed craft knife. The seals were hard and the o-rings were a bit flattened so I think it needed doing. Certainly, before replacement the pistons were looser in their chambers.
New jobs:
The car's throwing up three fault codes which I assume have been there since I bought it.
- P0344: Camshaft position sensor A circuit intermittent (this is the inlet cam sensor)
- P0365: Camshaft position sensor B circuit (this is the exhaust cam sensor)
- P1620: MAP cooling thermostat control circuit signal high
It looks like I need to replace both camshaft position sensors and the thermostat. I don't like the idea of the thermostat being faulty, but the car hasn't overheated at all yet.
Bonnet release: During the vanos/gasket work I closed the bonnet with something resting in the left hand side of the engine bay. I had to pretty much force the bonnet back open and now it's coming unlatched whilst driving along (not completely - it's being caught by the manual safety latch thankfully). It's bloody dangerous anyway. I don't know where to start with this. The bonnet release still works normally when it is closed, but I guess the latches are now loose or broken somehow. Kicking myself about this one - such a dumb mistake.
Anyway, it was good to start making some headway on the car. Still a long way to go.
James
