May 4 - car work

We got drizzle, sometimes heavy, on and off all day.  That didn't stop me from working on the car.

First up, I changed the pre-cat O2 sensors.  They were hard to get at, my offset 22mm wrench too long for the space in there.  I could "almost" turn it enough to reposition the wrench to move it another part turn.  Almost doesn't cut it.  Vice Grips and Crescent Wrench helped; didn't take long overall.

I started the car up and the 76 - throttle body sensor code - didn't come on ... have I fixed the problem ?  Time will tell.  Sandy went to the market with the car and the code had come back on.  Oh well.

Since there was still a lot of rain on the Doppler, I made my decision that this would be car day, beyond the 1/2 hour to replace those sensors.

First -- out with the fan.  That was quite easy with the correct wrench and considering that it had been removed not long ago and tested to be easily freed just a week ago.  The fan comes out with the fan clutch bolted to the center of it and the fan clutch screws onto the water pump.  The fan & clutch come out at the same time as the shroud, no room otherwise.  The last time I had it out, I'd reached down inside and removed the fan from the clutch using an allen key, not even being able to see the bolts.  This was a lot easier.

Next, drain the coolant, put a bucket under the coolant expansion tank and unscrew the plug.   Remove the coolant expansion tank cap (there isn't a radiator cap, per se) and let 'er drain.

Next, remove the thermostat.  There are four bolts and an electrical connection.  The way this thermostat operates, it's normally open and a solenoid closes it depending on a temperature sensor.  Then remove the hoses from the thermostat, dump coolant onto the driveway ... whoops, move bucket and catch that coolant.  I don't want to leave too much coolant around because it's temptation for Abby, since it's sweet, but it's devastating to dogs.

I can see where the thermostat has been leaking -- sweating, actually -- through the rubber seal to the engine block.  Well, that will be corrected.

Next, will I try the water pump ?  Ok, let's go for it.  Following the instructions, but not really understanding, I attach an allen key to the belt tensioner and turn it counter-clockwise.  That loosens the pulley but doesn't really loosen the belt.  What am I missing ?  Well, I found out later as I was putting things together, that had I turned it clockwise, I'd be pressing against the belt tensioner spring and loosening the belt.  As it was, I couldn't figure out how to loosen the belt.

I removed the extra pulley on the alternator, assuming that somehow I'd figure out how to get the belt back on, but sweating.  Four bolts hold the pulley to the water pump.  Four more bolts and the water pump is loose -- both loose, that is, after a little tap, not much else.

The water pump is now out; it's in good shape.  These in-block water pumps are much less prone to failure than the old external kind, because there's less to them.  The old OEM part has a plastic impeller; my new, upgraded part, has a metal impeller.  That should keep me for another million miles.

In with the water pump, four bolts.  On with the pulley, four bolts.  On with the belt.  Now, how do I get that guide pulley back into place on the alternator ?  Stand on bumper, put body weight on belt, get it over the pulley. Tighten that pulley.  Put allen key on belt tensioner, turn clockwise and tighten, see the belt tension release .... due ... now I see how the belt tensioner works !  This would have been so much easier !!!!

Put in new thermostat, four bolts.  Attach hoses and electrical.  Replace fan & clutch and shroud.  Attach electrical to shroud.  Mostly done.

Back under car, tighten plug.  Break plug.  RATS !  Hope it's tight even though head is broken off plastic plug.  Add coolant to tank.  Start engine.   Go through several cycles of "coolant low" and refill as air is worked out of the cooling system.  Throttle Body sensor code comes on some of the time, not consistent as before.  Drive around the block, watch temperature vary between low 80'sC to normal operating at 97C.

The Fedex man shows up with more parts.  Replace the engine air filter and cabin filter.  That delivery also has the same filters for the M5 and 330xi.  They need a little TLC as well.

We went out for dinner with Harris and Debbie, over to the local Thai place.  It was excellent !  We drove -- there and back and the Throttle Body 76 code never came on.  Did replacing the O2 sensors plus the easier breathing of the new air filter stop the engine from sucking air through some miniscule crack after the Mass Air Flow sensor and thus get rid of that code ?  I can only hope.  Today's errands will tell -- this morning will also tell whether I'm getting any leaking out of that broken coolant expansion tank drain plug.

I went online and ordered a new plug; two for good measure.  It's only $5 but without the plug ... well, perhaps a pared down wine cork might work, but only after I drink the wine !

Timing of all this is good.  I've got a week+ before we leave so any shake-out issues should appear in the meantime.

How much did this cost ?   How much did I save ?  The O2 sensors were about $80 each; the thermostat and  water pump both sub $100.  From BMW they'd have been about 1k, so I saved about $600 on parts.  On labor, I probably saved at least 4 hours @ 200.  So I probably saved about $1400 or so on the work.

If the throttle body sensor problem has been solved, that saves a bunch of diagnostic work and whatever else.  BMW might have just changed that part as well, which would clock in around $800, including parts.  I can only hope that this problem has been solved as well !

Time will tell.

Today -- I sure hope to ride my bike !  I can see lightening out to sea even as I sit here.

It's our anniversary.  32 years; >35 together.  Where has the time gone ?

Onward !