SD didn't start after city driving

[Robert W. Roe]

Last night we had the SD in New York City, crawling around mid-town Manhattan traffic for at least an hour, with the AC on. I finally found a free parking spot and parked, shut off the car, and about 5 minutes later decided to move the car a bit closer to the curb.

When I tried to restart the car, the temperature guage was close to 115 deg C, and the starter didn't crank at all. No click, no cranking whatsoever. I did hear the aux fan running. I had 12 VDC without the glowplugs on, and the alternator does seem to be charging. After jiggling the trans selector a few times, and letting the fan blow for maybe 15-20 seconds, the starter kicked right over and the car started fine.

My question is, is there some sort of "thermal overload protection" that wouldn't let the starter solenoid engage, or could I have a problem with something else? I figure the whole starting system electrically anyway, consists solely of the battery, transmission safety switch, ignition switch, starter solenoid, and starter.

After getting home, I tried to restart the car, and it fired right over no problem. Should I be worrried about getting stranded or is this a fairly common MB glitch? Any thoughts appreciated.

Thanks,

[MikeTangas]

"After jiggling the trans selector a few times, and letting the fan blow for maybe 15-20 seconds, the starter kicked right over and the car started fine."

Maybe you just weren't fully in park or the shifter bushings are nearing time for replacement. If you had power to everything, but no starter noise or action, and wiggling the shifter allowed it to start chances are it's one of those two scenarios.

[Robert W. Roe]

I'm wondering if the extreme underhood temperatures somehow may have contributed to this. I do recall the car starting after I cycled the tranny selector all the way from P to L a couple times. I'm hoping it won't give up the ghost all at once. I have a driver's side power window switch that gets flaky every few *months*, and as long as it's that infrequently, I won't pull the switch...yet.

"Maybe you just weren't fully in park or the shifter bushings are nearing time for replacement" Would these shifter bushings typically be replaced during a tranny rebuild?

Anyway, thanks for the reply. I just wanted to be reassured that I won't be stranded somewhere. Electrical intermittents can be fun, hopefully this is not a bad one.

[engatwork]

pretty normal and more than likely does not have anything to do with the starting thing. Whenever you shut any car down the temp will rise like that.

[Robert W. Roe]

The car has been starting fine all week now. No mid-town Manhattan traffic lately though, just some grocery getting runs around town (small town)...

I can't remember right off who gets credit for the "purple wire solution" to turning over the engine during valve adjustments (may have been Mr. Lewallen), but next time it happens, go to the terminal block on the right fender and check voltage between the purple wire and ground while someone turns the key. No voltage..and then theres some interlock problem. I'd tell you to jump from the positive terminal of the battery to the purple wire but it may not be safest...got to be sure its in park or neutral, brake set, etc.

If you do have voltage to the purple wire but nothing is happening, then there may be an intermittent short in the starter solenoid that's temp related.
Ernie

[Robert W. Roe]

I just had this no-start reappear twice now, and I just had my steering gear and rear swaybar links done, along with an oil change :| The last time was at lunchtime today. I had my door open, and I could hear a distinct "click" each time I tried to engage the starter. After cycling the shifter about 6-10 times, I finally got her to kick over.

I'm thinking this rules out the neutral safety switch, and wonder if it's the starter or the starter solenoid? I'd like to get this fixed, without my local independent replacing all of my starting components. Not that they would, but my wife is becoming afraid of getting stranded somewhere far away. Please help, mostly because I dislike taking long trips in her Subaru Legacy (too cramped for larger people.)

Thanks,

[psfred]

Robert:

Several possibilities come to mind:

First, the starter solenoid is getting old and the resistance is going up. The hotter it is, the more resistance, and when really hot now it won't close the contact to energize the starter. The loud click is the solenoid pulling the starter out, but if it doesn't pull hard enough, no juice to windings and no start. It also may have finally burned up the copper contacts, so no juice to starter.

You may also have used up the brushes in the starter motor, so even if the solenoid engages properly, the windings still aren't connected. Bang the solenoid a couple times and they shake free enough to contact, and off you go.

And last, you may ahve a bad connection at the starter or ground strap(s) -- my Volvo TD did that, sometimes just clicking the solenoid and nothing more. I had reconciled myself to the $400 for a replacement (without installation!) and discovered that the positive cable connection was bad when I started to remove the starter. Cheap fix. Cranks like crazy now!

Good luck -- I hate intermittant electrical problems!

Peter Frederick

[Robert W. Roe]

I had a feeling that I'd better check all my electrical contacts. I want to clean them all with a Scotchbrite pad but I just haven't had time. Perhaps it's a coincidence, but my AC has begun to blow warmer than usual coinciding (almost) with the increase in the frequency of the starting problem.

I wish I knew where my starter solenoid is, in case I have to tap them a couple times to get me going. I hope my Haynes or Chilton's book has some locations and/or pics. I've often wanted to see a good exploded view or a picture of an MBZ engine bay, with all the parts identified... anyway thanks again for the ideas... I'll keep you guys posted.

In spite of the problems, I still love the car; I just hate being stranded...

[psfred]

Robert:

Starter is on the passenger's side below and behind the turbo if you have one. Solenoid is on top. The connection is under a rubber boot on the big cable (direct from the battery).

Take the negative battery cable off before toching anything -- a direct short can cause the battery to boil or explode when the positive cable welds itself to the frame or some other ground.....!

I would clean the cable and associated washers with sandpaper, then lightly grease them before putting them back together. The bolt on the solenoid is usually copper, so don't overtighten.

You might consider taking your SD to an alternator/starter/battery place if one is around -- nothing different between an MB and any other car as far as function of the starter goes, just much better quality. They guys there, if it is a reputable outfit, see this kind of stuff all day and will be very helpfull -- they can check things like current draw and know how to bypass the right bits to find out what isn't working.

If the starter is bad, buy a new one, or if you are frugal, a Bosch remanufactured one. The windings are usually shot when an MB diesel starter quits working, so the usual "clean up the commutator and put new brushes in it" rebuild won't be any better than before the rebuild. Bosch replaced the windings, too.

I'm not sure where the ground strap is on a 126 chassis -- should be one from near the starter to the frame. It is a woven flat wire thing about 3/4! wide bolted to the frame and under a bolt somewhere on the block.

Please remove battery cables from the battery before taking any other connections loose!

Peter

[Robert W. Roe]

Thanks, Bill and Peter, for the replies. I've been procrastinating about cleaning all of my electrical connections, but it sounds like this is a no-cost alternative to having a shop troubleshoot my electricals. Winter is coming, and eastern PA isn't a friendly place to get stranded in subfreezing weather.

I'm sure I'll have more dumb questions once I start tracing heavy wires coming from my battery, but cleaning all of my contacts will be a good first step. Maybe I'll luck out and just have some corroded terminals. Thanks again, Bob