Originally Posted by simey_binker
Well, might as well introduce myself; I'm a 27-year-old mechanical engineer, who has mostly driven turboed RWD Volvo wagons (4 of them). The first burnt to the ground, the second crashed, the third went to the yard, and the 4th my wife flipped on the highway. So now I drive a 2002 BMW 325i wagon in manual. nearly 300k kms.
I'll keep this short to avoid any "TLDR"; I've got problems:
#1, when going over bumpy roads, the front suspension "chatters" a little. It was safetied about a month ago, and a tierod replaced. at time of purchase, I inspected those rear a-arm bushings that seem to go in the front suspension (apologies for not the correct term), and they checked out. I haven't crawled underneath yet, but I'm suspecting the anti-roll bar. It sounds like the chatter or knocking you'd get from a strut not seated properly.
#2, on warmup, the idle fluctuates. When the car is cold, it's ok. When the car is warm, it's ok. when the car is nearly at operational temperature, the idle fluctuates, sometimes stalling. I've heard about the plastic intake boots cracking, but wouldn't that affect the car all the time, and also throw a code (no engine light on dash)? I don't want to automatically attribute it to this, but it seemed to arise after I siphoned gas from a parts car which makes me question the cleanliness of said gas. however I've gone through 4 tanks since then, so the only possibility would be the injectors. With all the stories of Vanos going, could it be this? I seem to lose oil very slowly. what are the indications of a Vanos needing fresh seals?
#3, at time of sale, the seller said that the previous owner had put in a shorter gear in the diff (or, he attempted to communicate this to me but I had to read between the lines as I don't believe he understood completely). lower gears don't seem unreasonable, but on the highway and in 5th, the car is operating at 3500 rpm at around 110-120km/h. this means I don't need to downshift to pass, but I'm also skeptical of the fuel efficiency. seems like I cruise around 8L/100km which isn't bad, but perhaps this could be better? what are you guys running?
Other than those things; it's a great car. I'm glad I've put the mid-80s and early 90s Volvos aside to join the rest of the population in the new millenium.
Adding to above posts:
1) Top strut mounts, and end links (loose, broken or deteriorated) fit these symptoms. If its been 100k+ km since your last suspension refresh, its already time for new struts and shocks, rear shock mounts, FCABs, LCABs, etc. if you're doing it by the book.
2) Could be a torn boot or vacuum leak as mentioned. I would also go ahead and replace the voltage regulator on the alternator (Hopefully your have a 120a Bosch - cheap and easy), as this is not only preventative maintenance, but will also solve a plethora of other electrical, idle, and misc. E46 personality quirks you're bound to have. Oil consumption even if 1 quart every 4k is within spec and I'd expect it for such a high mileage engine. At the bare minimum I'd replace the Valve Cover Gasket (VCG).
3) Use the differential calculator the other poster linked. Sounds like at 120km/h you're a bit high. I know at that speed I'm less than 3500rpm. If you're running the appropriate 91 octane WITHOUT ethanol (Shell V-Power ftw), you're achive better fuel economy figures.