What could be wrong with my car?

[L1FE]

I'm going to take my car in to see a mechanic, but I'd like to get an idea of what I might be dealing with before I send my lamb into the lion's den. I drive an automatic, '92 BMW 525i and it has just over 110k miles on it. Everything runs great (except for the electronics) and so far I've been very lucky that such an old car has given me so few problems.

However, last night, after putting the car into reverse, I hear a loud BANG similar to a large twig snapping. At first I thought it was just that and was worried about it popping one of my tires. Well, I put it in park, get out and see that all the tires are just fine, so I get back in and put the car into drive. At this point, the car starts to jitter a bit so I thought that maybe when I first got out the tires were just beginning to deflate. Get out again and see that the tires are just fine. Put it in drive to see if I can reproduce and the ride quality goes back to normal - except for a loud whirring sound (like you're winding something up) and that car shift knob vibrates a lot. It doesn't feel like I've lost any power, and the car handles normally, so what the heck could have broken?

Thanks in advance since I'm a total car nub.

 

[Demon-Xanth]

Engine mount.

Edit: actually, more likely harmonic balencer.

my dad had one go out on his work truck a while back, the company mechanic couldn't figure out what was going wrong with it, so he drove it until it exploded, yanked out half a dozen hoses but kept running. A 454 needs one of those. The 525's I-6 wouldn't need one quite as much.

 

[L1FE]

Any idea on how much a harmonic balancer would cost to replace? Doesn't it always seem like when you're trying to save money, shit starts blowing up??

 

[Demon-Xanth]

Are you doing it yourself, and do you have a pulley puller? I'd guess a $50 part if it was a Chevy, so probably $150. If you're having a mechanic do it probably an hour of labor. I don't know how the timing belt is arranged, but if it comes off the balancer you might as well have that done if it's been a while

 

[Zenmervolt]

There's something off about having an older German car while also trying to save money...

More relevantly, the 525 will not have a harmonic balancer, so it cannot be that. The inline 6 is naturally balanced without the need for any additional balancers.

Most likely in my mind is something in the transmission or a transmission mount. The whirring noise worries me as that is typically an indicator that something's screwy in the gearbox. Take the car to a dedicated transmission shop or a dedicated BMW shop (not necessarily a dealer) and have it inspected.

ZV

 

[L1FE]

Originally posted by: Zenmervolt
There's something off about having an older German car while also trying to save money...

More relevantly, the 525 will not have a harmonic balancer, so it cannot be that. The inline 6 is naturally balanced without the need for any additional balancers.

Most likely in my mind is something in the transmission or a transmission mount. The whirring noise worries me as that is typically an indicator that something's screwy in the gearbox. Take the car to a dedicated transmission shop or a dedicated BMW shop (not necessarily a dealer) and have it inspected.

ZV

Hey now...I've had the car for like 10 years! up to this point, it's never given me any major trouble...hmm this sounds like an expensive endeavor!

 

[Zenmervolt]

Originally posted by: L1FE

Originally posted by: Zenmervolt
There's something off about having an older German car while also trying to save money...

More relevantly, the 525 will not have a harmonic balancer, so it cannot be that. The inline 6 is naturally balanced without the need for any additional balancers.

Most likely in my mind is something in the transmission or a transmission mount. The whirring noise worries me as that is typically an indicator that something's screwy in the gearbox. Take the car to a dedicated transmission shop or a dedicated BMW shop (not necessarily a dealer) and have it inspected.

ZV

Hey now...I've had the car for like 10 years! up to this point, it's never given me any major trouble...hmm this sounds like an expensive endeavor!

I'm just giving you a hard time having had older German cars myself. They don't fail often in my experience, but when they do... Yowza. Overall I don't think that the average maintenance cost is much different from other older cars, just that German cars tend to consume money fewer times but in larger chunks as opposed to small chunks spread out over time.

If it's just a mount, it may not be that bad. Honestly, if nothing else is wrong, even if it is the transmission I say just get it rebuilt and keep the car. The transmission will still be cheaper than payments on an equivalent car.

ZV

 

[L1FE]

Thanks for the advice! I'm taking it in tomorrow morning to a shop specializing in German cars. I hope it's nothing serious since I love that car...

 

[exdeath]

Broke a u-joint maybe? That might make a bang when it broke, and if it was still holding the drive shaft in, it would be loose and cause drive train noise and vibration like you're describing.

 

[Demon-Xanth]

Could also be the carrier bearing siezed up then tore the rubber isolation and the whirring you're hearing is the bearing spinning in the housing.