Is the aircon broken?

Homer_Bart

Well-Known Member
Joined
Sep 10, 2006
Messages
991
Location
Singapore
Car(s)
2007 BMW 320i
Hi guys. It's a really stupid title name but I don't know what will be more apt since my mechanical knowledge is extremely limited.

So "my" BMW 320i E90, built 2007 and currently with 90000km, has been having problem with noises and engine lately.
First, the engine of late has been running much louder than before, it used to hum quietly but now it drones loudly, and the noise difference is especially apparent when heard outside the car.
Secondly, the car's acceleration sometimes feels jerky. I depress the gas pedal a little, there'd be minimal gain in speed for a fraction of a second or sometimes longer, and then the car jerks forward. When it happens on a "cold" morning of 28 degrees, I understand, but sometimes it just happens on a hot day of 37 degrees and the engine is very or extremely warm.
Thirdly, the engine makes rattly noises. When in Drive at higher revs and the aircon off, the car sounds fine. But with the aircon on in drive but in idle or lower revs, the noise is rather alarming. In Park, the rattly noise isn't there, either with the aircon on or off.

What's the problem here? Is it the timing belt?
Thanks!
 
Last edited:
Sounds like you have multiple problems, not just one. However, from the description and the fact that it's an E90, it sounds like your problem is that the gearbox is going out.
 
The only major servicing done recently was to change the hoses, which leaked oil. My friend's dad's 2005 E90 also has a regular gearbox issue, clunks and refuses to change gears, and when it does the car jerks.
I presume the gearbox only has association to problem 2? I can live with the jerk, it's not so significant, but I'm really worried about the hefty bills that are to come as it needs a timing belt change etc. at 100k km.
 
Both the rattling and noise can be attributed to a failing automatic gearbox. The jerkiness could be due to that or due to the sometimes-wretched BMW throttle by wire system.
 
Now I know where the problems are, I'll take extra care to keep this ailing gearbox holding for a little bit longer to keep the costs spread out. Thanks Spectre!
 
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