I need a little help thinking through something odd that happened the other day. The car's history as it pertains to this set of issues is that we put a rebuilt starter unit on the car about two years ago, and have had no starting issues of any kind until now.

The battery voltage and current have been checked to exhaustion. The battery is new within the last 3 weeks following the death of the old one during the first cold snap of this winter. I've verified my charging voltage (13.9 at idle, according to the tester Advance used when they installed my new battery) and have checked with my own multimeter to my satisfaction. The posts and clamps have been cleaned and firmly fastened.

The car currently has its summer oil in - Rotella 15w40 dino - I'll be putting something lighter in for the winter sometime over Thanksgiving. Last winter was milder; we only had about two below-20 days all year and it wasn't an issue. So cold/thick engine oil is definitely a factor in this particular case.

All six glow plugs are brand-new Bosch plugs with less than two months of use on them.


Now, my problem:

We experienced our first dramatically colder weather event of the season last weekend - the car sat for well over 24 hours in 15-20 degree air temps with 4 inches of snow sitting on top of it; at the time of my start attempt, the air temp was 19 degrees.

After running the glow plugs a little longer than normal, to give me a better shot at this start (Which shouldn't have been this hard; I did it last winter a few times with no issues). Turned the key and heard a noise like you'd expect to hear if the starter teeth and/or flywheel teeth were damaged or rounded off to the point that they were crunching against each other instead of engaging each other. It wasn't quite such a dramatic noise; it didn't sound like they were ripping each other apart - but obviously the engine didn't engage.

So, after a brief panic moment (I had a friend with me; we were on our way to a concert) - I re-glowed for luck and retried it - the thing engaged perfectly. Engine started with no more difficulties. Engine wasn't even THAT hard to turn over through the thick oil; starter speed was reduced a little bit by the cold and the oil stiffness, but not significantly enough to sound like it wouldn't start.

The worst-case scenario here that I can imagine is that I either have a starter tooth broken (relatively easy fix in that the starter is all that has to be replaced) or a damaged place on the flywheel. I see this as a possibility... but also find it hard to believe it likely. I can't see that the failure of this thing can possibly be coincidental with the first frigid weather the car has seen in 11 months.

I'm wondering if it's possible that the starter gear either was moving slowly (due to thick lubricants in it? not sure about my understanding of starters) - and was already spinning too fast to engage the flywheel without grinding the gears when they finally reached the meshing point - or else, possibly the gears meshed, the starter suddenly hit a wall of hard-to-rotate-engine due to my oil thickness and the extreme (for the conditions it had been seeing) coldness, couldn't spin the engine over a complete revolution in those circumstances, lost its momentum, and retreated just far enough to disengage the flywheel and then got back up to speed and tried to re-engage.

Are either of those cold-related situations likely explanations? Or am I facing flywheel/starter tooth trouble and this was my warning?

I'm paying careful attention to it; we charged the new-from-Advance group 49 1000/850CCA battery up with our trickle charger just to be sure it was completely topped up from the factory charge, and I'll listen to the thing when I crank for any trouble for the next few starts. Preceeding and succeeding this event, I haven't heard any unusual noises at startup at all; I always listen closely and I certainly haven't heard anything that sounded like gears clashing or teeth getting crunched until now.

If I'm panicking, it's just because I don't want to have a major repair (flywheel) now. I'd rather know what's going on than keep guessing until it leaves me starter-less.

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~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

I have never rebuilt a starter. I can only say that 75% of my rebuilds do not perform the way anew ever does or would be expected to work. The failures I have encountered sound very simialr to yours.

Do question the rebuild's source

Do follow up on your warranty if the problem persists

__________________

In my opinion, your symptoms are consistent with the grease on the bendix being thickened by cold weather, hindering the full extension of the bendix. Not something to worry about unless is happens repeatedly in which case you could remove the starter, clean the shaft and put a light coating of a synthetic lubricant on the shaft.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

That's what I wanted to hear; that it is at least technically possible for this situation to be the problem. Makes me a little less panicky about the more severe things it could be. Particularly if this rebuilder used thicker grease than they should have.

Fortunately, it's lifetime replacement.

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

There are a couple of potential scenarios.

-The one that has been described, although it would seem to me there is something wrong with the installation if the starter motor is engaged before the pinion gear is engaged.
-The teeth on the ring gear can be ground off in the particular positions the engine stops in, if the starter pinion gear is allowed to grind its way into engagement. This can be an issue and will eventually grind off the teeth, and the noise is nerve wracking as it happens. Loud, shrieking noises. In that case you need a new ring gear pressed onto the flywheel.
-And, there is another possibility that the clutch in the "bendix" is bad, and you are hearing it grind on itself. Technically I am not clear these things have a real "Bendix" helical gear. I think it is a solenoid that doesn't start the starter motor until the solenoid reaches the end of its stroke.

At the least you need to remove the starter and have a rebuild shop test it. While it is out, stick your finger in and feel the flywheel ring gear teeth.

Good luck, Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

On my 2 1980 300 TDs, once the starter is out, I can look in and inspect the ring gear. I turn the engine with a wrench on the power steering pulley nut. One of mine had the "failure of starter gear to engage ring gear" problem pretty badly. The ring gear teeth looked a little worn in a couple of places, but not really bad looking. I cleaned and tightened ALL electrical connections, including the engine ground strap, and the problem went away.
Steve

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1980 300 TD

1997 Dodge Pickup/Cummins 5.9 12-valve