BMW Secondary Air Pump Replacement - Progress Update 1
My work in replacing the secondary air pump in my 1998 BMW 323is has been positive. Last Sunday, I performed about 80-percent of the total work involved.
This included replacing the non-return valve and gasket attached to the exhaust manifold. The valve is actually the cause of the pump failure; water got past the valve and entered the pump, which contributed to deterioration of the pump motor. This was pretty easy. I used a 10mm socket wrench with extension to work on the two nuts affixing the valve to the manifold.
The more difficult and frustrating steps involved removal of the non-functioning pump. The pump rests on three vibration-dampening rubber posts which are attached to a hard plastic mount. The mount is attached to the car chassis using three 10mm screws. The mount was easy to remove. The rubber posts connecting the pump and the mount were a subject of concern from the outset. Most of the how-to's state that these posts are extremely fragile and must not be subjected any torsion. I broke the first post in a matter of five seconds. The second post broke just as easily. The third and final post was broken by me in a fit of frustration.
To exacerbate the problem, the rubber posts are as expensive as they are fragile. The OEM replacement costs over $16 per post. Multipled by three, that's a total cost of at least $48. Fortunately, one of the how-to's suggested purchasing general-purpose rubber posts (McMaster part 9376K57) matching the OEM specifications. These are only $1.48 per post. I should be receiving the posts today, and will complete the repair this weekend.
So, for the last three days I've been driving my car with the new non-return valve installed and no secondary air pump. The biggest difference is the sound of the engine during the first two minutes of driving. It's a lot louder. It sounds like the mixture is extremely rich. I'm really hoping that the installation of the new pump will resolve the noise and 'check engine' light issues.