something locked up - help

[infurno]

Had my car towed today.

Its smoking from the belt area, a lot of smoke from the front of the engine. A lot of noise, like a loose belt but everything seems tight. I think something locked up, I have a hunch its the alternator but i don't know if thats possible. Someone mentioned possibly air compressor.

One of the belts looks like its in really bad shape, with gashes and torn edges.

http://www.buysmartpc.com/temp2/DSCN4826.JPG

The belt doesn't seem too damaged in this photo, but its just the spot it stopped at. Its the one by the red mark, connecting to the alternator. im not sure if this is the belt that is smoking, its just the one in the worst condition.

Is there anything belt driven that can lock up? And where should I look first?
- im not sure where to start.

[Dave M]

Well, to answer your question. Yes, belt driven components can seize.

If it smells like burning rubber, you've got a locked-up-something-or-other. First off, make sure your engine isn't overheating, then get it running and look a lazy/seized pulley. Shouldn't take long its its bad enough to create smoke.

Alternarors tend to continue to spin and may shed metal bits as the bearing explodes. Not sure about AC components as I have little experience. The water pump is the most important thing down there, so make sure you don't driove it if you determine its pooched.

Dave

[DaveVoorhis]

Remove the sizzled belt (it's trashed now, anyway, and should be replaced) and try turning the water pump, alternator, A/C compressor pulley, power steering pump, or whatever devices the belt operates. All should turn easily by hand except the crank pulley, but it's driving the others so it's not the problem. I've known A/C compressors, power steering pumps, and water pumps to seize. As mentioned, alternators usually disassemble internally rather than seize.

[infurno]

Thanks a lot, i'll get started first thing in the morning.

Yeah the belt is toast, im defiantly buying one with whatever seized part it is I need.

The car really can't be driven anywhere. It wont stay on, it dies without some gas.

Im positive the engine is not overheating, it smokes when the engine is cool after turning it for 10 seconds. Also the smoke is coming from right behind the radiator, not the cylinder side.

I'll try to figure out but if anybody has any tips about the best way to get to the belts and parts down there I would appreciate any pointers.

[Rus]

It would be helpful to know what kind of E34 this is. Looking at your picture, it looks a lot like my 535i. If it is, then you will need to remove the radiator fan, loosen the nut on the belt tension adjuster and move it in by rotating the larger bolt head that faces the radiator (these tensioners love to strip out their teeth, so be sure you loosened the securing nut on the back). After you do this, you can remove and replace the belt. There should be three tensioners total on an M30 engine. HTH

[infurno]

Your right, sorry. Its a 1990 M20 with 265k miles

I think the process will be similar, the fan has to go for sure.

I remember the belts easier to reach on my 1984 533i E28 with the m30 but im not sure if its the same m30 as in an e34? Looks different. - wish i could just swap.

i doubt its wise to replace a 1990 m20 with a 1984 m30

[Ferret]

Rule of thumb:
Rubber burning smell = seized ancillary/loose belt
Plastic burning smell = seized AC compressor

AC compressors make that smell because the plastic clutch mechanism gives up before the belt starts to slip...

[Dave M]

Is there a belt on the M20 dedicated to AC ONLY? (M50 is like this)

If so, remove it and you can safely start the car to determine if thats the issue. If it is, then you've bought yourself some time and can drive around without AC. Someone who knows the M20 can qualify this or tell me I'm out to luch.

Dave

[infurno]

My crappy repair book dosnt even show the front of the engine...

It looks like the belt connects to 3 wheels. The alternator(1), the wheel behind the fan(2), and the big wheel right under the fan wheel(3).

(2)o o <- alternator(1)
(3)O

I can't move #2 & #3 obviously. Im not sure how the fan clutch or anything like that works, if that even has anything to do with it.

Should I be able to trun #2 by hand?

[[1990]525]

Is there a belt on the M20 dedicated to AC ONLY? (M50 is like this)

If so, remove it and you can safely start the car to determine if thats the issue. If it is, then you've bought yourself some time and can drive around without AC. Someone who knows the M20 can qualify this or tell me I'm out to luch.

Dave
I've had my AC belt disconnected for quite some time (just cut it with scissors :D). (m20)

[Ferret]

My crappy repair book dosnt even show the front of the engine...

It looks like the belt connects to 3 wheels. The alternator(1), the wheel behind the fan(2), and the big wheel right under the fan wheel(3).

(2)o o <- alternator(1)
(3)O

I can't move #2 & #3 obviously. Im not sure how the fan clutch or anything like that works, if that even has anything to do with it.

Should I be able to trun #2 by hand?

2 should be your waterpump and should easily turn by hand... I think?

[Rus]

Your pulleys are as follows:
1) Alternator
2) Water pump pulley
3) Main crankshaft pulley

1 and 2 should move freely with the belt off. The Alternator is the one with the tension adjuster (which is visible in the first picture you posted). HTH

[DaveVoorhis]

the wheel behind the fan(2) ...

Should I be able to trun #2 by hand?
Yes, with the belt removed, of course. If you can't, your water pump has seized.

[infurno]

I was hoping it was something easier to get to...

Looks like im going to have to buy a better repair manual.

I would appreciate it if someone could just summarise what needs to be done to get to the pump so I have a better idea of what im getting into.
I don't suppose this will be simple.

[Ferret]

I was hoping it was something easier to get to...

Looks like im going to have to buy a better repair manual.

I would appreciate it if someone could just summarise what needs to be done to get to the pump so I have a better idea of what im getting into.
I don't suppose this will be simple.

It wont be that hard, while you're at it change your visco fan coupling so that wont have to be done in the near future :D

Have a look at:
http://www.bmwe34.net/e34main/Maintenance/Engine/M20Timing.asp

yes it's about the timing belt but it's got some pretty damn good photos and explains how to get the pump in and out/belts on and off.

[infurno]

Thanks! That helps a lot.

Anything else I should change while im in there?
Timing belt has ~40k

[infurno]

Fixed it. That was really easy and cheap.

Its running very well again.

I wish I went ahead and bought all new belts, there was another that looked pretty worn.

The timing belt was not very tight... is it meant to have just a little slack?