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Odd intermittent starter noise

Started by daantjie, 27 April 2020, 08:56 PM

daantjie

Hi guys

This one's been bugging me for a while but has been low on "the list".  I am getting a weird noise from the starter intermittently, usually when the car has sat for a while.  It is not a grinding noise, rather a higher pitched whining noise.  Also it coincides with a "no start" so then I back off the key, and it then always starts on the second attempt with no further noise or drama.

Also, once I take it out for a spin, and then try and restart it after stopping for a coffee or such, it never makes the noise again upon restart, I barely touch the key and it fires immediately and strongly.

I have receipts from the previous owner where both the ring gear and starter were replaced somewhere along the line, so I know for sure it is not the originals.

Quite odd, no?  I have researched on sticky Bendix gear and such but I profess not to know much about electrical so maybe the brain trust here can weigh in?

Cheers
Daniel
1977 450 SEL 6.9 - Astralsilber

chinny4290

I have the same issue. The only thing I can think of is that a starter replacement might be on the horizon. Not sure when. It only seems to happen in cold weather for me and after sitting for a while. It comes across as the starter is seizing until actuated.

Either that or it needs to be lubricated or cleaned, if such a thing is possible.
1975 W116 280S - SOLD
1994 W124 E320 Coupe - Gone

CURRENT - 1974 450SEL

rumb

The Bendix has a bunch of ball bearings that can be cleaned up. They are loose on the spiral that pushes the Bendix out so they are quite fun to do. One starter I fixed was missing several bearings. The Bendix gear was cracked and I managed to find a new one. I have extra ball bearings if you need them.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

revilla

Quote from: rumb on 28 April 2020, 06:46 AM
The Bendix has a bunch of ball bearings that can be cleaned up. They are loose on the spiral that pushes the Bendix out so they are quite fun to do.

Exactly.  Mine, only during cold mornings, used to do that until I changed the bendix (000-151-71-13) which is still available, not at all expensive and so easy to replace.  There's a cylindrical insert that wears, causing the bendix to wobble slightly then sticking which makes the starter turn without engaging the flywheel.  It's a good opportunity to change or just clean the selenoide and the mechanism/arms that pushes the bendix out.  Other failure mode I have seen  is flywheel missing or worn teeth. The motor itself is quite robust rarely going bad. Many change the whole starter but most times is the little cheap bendix causing that problem. Fun little project.

Cheers

daantjie

#4
Thanks guys

I guess I see a starter pull in my future, oh joy :o

Can I try and be lazy and lube the bendix with the starter in situ ;D?
Daniel
1977 450 SEL 6.9 - Astralsilber

rumb

You can be lazy all you want but the starter won't get lubed.  :D the Bendix is the part in by the ring gear.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

daantjie

Daniel
1977 450 SEL 6.9 - Astralsilber

revilla

Quote from: rumb on 28 April 2020, 12:16 PM
You can be lazy all you want but the starter won't get lubed.  :D the Bendix is the part in by the ring gear.

Right.

If your bendix is suffering (like mine was) from a worn almost none existing brass insert, grease alone won't do the trick.  With that piece no making friction with the starter axle, the little clutch/bearings won't engage thus it will turn freely without engaging the flywheel. Again, assuming it's your bendix the problem and not the selenoid/fork/etc. But it's highly probable it's the bendix acting up.

Cheers

Mattr

Another thing to consider: My blue 6.9 has a flat spot on the flywheel. If the car stops on that spot, I have to tap the key a time or two to get it past it, and then the car starts right up without issue. It makes a similar kind of noise, where it's a brief, high-pitched screech, and then the car starts.
1976 450SE 6.9 FrankenBenz (#2288?)
1977 450SEL 6.9 #2333

daantjie

#9
Thanks yes I guess it's time to take a hard look at the ring gear, kind of dreading this tho...It would really suck if the ring gear is toast after already having been replaced by the previous owner.  From the paperwork looks like it was done 10K miles ago, sounds a bit early for a ring gear to already be toast ???
Daniel
1977 450 SEL 6.9 - Astralsilber

daantjie

#10
OK so clearly I have too much time on my hands, let's blame Covid :)

I just went and did 15 starts from cold, garage is at approx 15C ambient.  1st crank, made the noise, then 2x good, then 4th one bad, then 5 - 10 over the course of the motor warming up to normal operating temp, no issues.

So it would appear that it is temp related, and thus I am going to assume (hope springs eternal ;D) that I have a gummy bendix gear on my hands.  Of course it is possible that on all 10 good starts it missed a potential bad spot on the ring gear, but I am going to again hope that this would be unlikely ;)
Daniel
1977 450 SEL 6.9 - Astralsilber

rumb

Anyone with a bad ring gear of course replacement is best, but since the motor tend to stop in the same place most of the time, one could remove the ring gear and put back on 90 or 180  degree offset. That would be a 95% solution.

The bear of course is you get to pull the engine and trans to get to the bugger.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

Randys01

Dodgey bendix Daniel....pulling the starter motor out is chicken feed for you... :'( disconcerting is the suggestion of a recon not so long ago however get into it!!

daantjie

Thanks all yes I think it's time to get stuck in as they say, let's not be lazy 8)
Daniel
1977 450 SEL 6.9 - Astralsilber

Lance

I had the same problem, was a loose mounting bolt.