Car won't start...but makes a strange noise instead

[miliue]

1992 BMW 525

I just drove to the auto parts store to get some UV dye to check for leaks in my AC system (just replaced the compressor and retrofitted from R12 to R138a or whatever it is last weekend) anyway, the car ran fine after the retrofit. And ran fine 10 minutes ago while I was driving around.

So, I put the dye in the system and ran the car for 10min with full AC and all that. Shut the car off, no leaks. Hurray!

But when I tried to start the car up again it acted like the battery was about dead. I let go of the key and it continued to crank, and then started up. I was kind of confused by this so I shut it off. Then this loud-ass noise (it sounds just like a vaccuum cleaner with a rock stuck in the hose or something) started coming from the engine. And now the engine won't crank when I turn the key.

I disconnected the battery and the noise stopped. But as soon as I connect the battery, the noise starts again and I can't crank the engine. All the lights come on in my dash like normal, the radio starts up, all that like normal when I turn the key, but the engine won't crank and that damn noise keeps coming.

It sounds like it's coming from the back of the engine bay near the firewall, but I can't see anything spinning or moving. I'm guessing it's some kind of fan behind the firewall...or the starter.

I need to fix this so I can drive to work tomorrow! Anyone have any idea what the problem could be? Thanks!

[joshua43214]

I have seen starters get stuck and run constantly before. Your comment that it continued to crank leads me to this. the contacts inside the starter will fuse and cause the pinion to remain extended and it to continue to crank.

After the engine starts, the huge ring gear will now be driving the tiny starter gear. in theory the one way portion of the starter gear will protect it, but its really only meant to deal with it remaimng engaged for a very short time. eventualy the windings inside the starter will kinda explode inside the case.

the sound you are most likely hearing is the oneway gear in the starter slipping. makes a really ugly grinding, stripping noise.

its possible the ignition switch failed and is feeding constant power to the starter as well, but by the sounds of it, your starter is toast, so you will probably need a new one anyway, just hook the battery back up with caution.

[miliue]

I have seen starters get stuck and run constantly before. Your comment that it continued to crank leads me to this. the contacts inside the starter will fuse and cause the pinion to remain extended and it to continue to crank.

After the engine starts, the huge ring gear will now be driving the tiny starter gear. in theory the one way portion of the starter gear will protect it, but its really only meant to deal with it remaimng engaged for a very short time. eventualy the windings inside the starter will kinda explode inside the case.

the sound you are most likely hearing is the oneway gear in the starter slipping. makes a really ugly grinding, stripping noise.

its possible the ignition switch failed and is feeding constant power to the starter as well, but by the sounds of it, your starter is toast, so you will probably need a new one anyway, just hook the battery back up with caution.

I smacked the starter with a rubber hammer and it quit making noise. The car starts "fine" now, heh. By "fine" I of course mean that it seems to be OK now but we all know it's just a matter of time before something explodes and/or catches on fire. It'll get me to work tomorrow though!

[632 Regal]

keep the rear seat bottom out of the car with a 1/2 inch wrench on the floor, since the starter id fubared you never know the problems you can have with this. stripping the flywheel gear is real bad. Get a used or new starter asap. I wouldnt recommend a used one but they usually last the life of the car = 300k miles or so. so if you find one with under 100k for a good price I wouldnt worry bout trying it.