Sunday, March 7, 2010

The Belly of the Bimmer...

The 325i turns 9 years old this month. At 63,790 miles, there are some good preventative things we can do. The list was on the last post, but this was the weekend to actually get it done.

A recent contribution to the BMW club magazine gave me some direction about how to tackle several jobs at once. The suggested best practice is to start with the simplest items first. This makes a lot of sense. If I get hung up on something difficult, I don't have a lot of parts for easy projects lying around. I think my wife was encouraged to see the items disappear from the floor piece by piece over the course of the weekend.

Friday afternoon I went ahead with the oil, air filter and cabin filter changes. I must be getting good at this, because I got it all done in 50 minutes.

Today, I started in with the fuel filter (the next logical task, because it can be done in isolation, unlike the water pump). The secret here was to get the car as high off the floor as comfortable. The filter is connected by rubber hoses and clamps (very different from the Benz) and working them free after 9 years proved to be a challenge. Rather than depressurize the system like I did on the Benz, I just opened up the gas cap, and it's important to be aware that there will be some fuel spray when the first hose lets go. How exciting! I've been getting crummy mileage around town as of late, so maybe this will help. The fuel that came out of the filter was very clean, so that's a good sign.

The next job was the water pump and ancillary projects. Step 1: Drain the coolant. I got some of it, but unfortunately, the block drain plug is in the most bizarre position imaginable. Somewhere behind the alternator, above the steering link, and in front of the exhaust manifold. I actually purchased a special wrench with a swiveling head, but no luck. It wasn't imperative, so I moved on.

Step 2: Fan removal. This was easier than thought as well. I actually purchase a set of special tools to make this happen. One tool is a thin strip of metal to hold the pulley still while you slide a thin 32mm wrench to loosen the fan. Once the fan comes off, it all lifts out of the engine bay.

Step 3: Belt removal. Very straightforward, no problems.

Step 4: Removing the pulley from the pump and the pump from the engine block. All simple.

At this point, I also tried to disconnect the hoses from the thermostat to replace it. Removing the hoses was real tough and I was hesitant to try too heard for fear of breaking something. Given that the water pump itself was in very good condition (I only replaced it for cautionary reasons and to upgrade to a metal impeller) and I was on a bit of a roll, I decided to dispense with the thermostat replacement and will hang on to it just on case.

Step 5: Replace pump, reinstall pulley. Easy.

Step 6: Replace belts with new ones. This was a little tricky, as you had to thread the main over 5 pulleys with one hand while holding the tensioner at bay with the other. Juggling is easier, but it got done.

Step 7: Replace fan. Worst part of the job. There is little to no room for your hands, and you have to spin the fan onto the new pump 1/16th of a turn at a time. I ended up trying from the bottom and calling in my wife for support. After a few minutes of swearing, my wife politely suggested that when I moved to the bottom of the bay, I needed to try and rotate it back on in the opposite direction (it's reverse threaded and confusing enough as it is). Voila - Her idea and helped worked.

Step 8: Replace intake ducting

Step 9: Refill coolant system. Messy and a little disconcerting the first time you do it, but relatively simple.

At this point, it's time for the ultimate test - starting it up and seeing what breaks. A 20 minute test drive to check proper operating temperature was a great success!

I haven't done a proper coolant flush in 5 years. What I added today probably helped, but that will need to be done by a professional. The thermostat can wait until something breaks, I figure. I spent roughly $400 on parts, and estiamte I saved about $5-600 on labor.

And speaking of professionals, the Benz is actually at the local indie shop getting some suspension work done. That will get a post of its own.

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