6.3

Hello folks... Happened once before and happened again today.

71 6.3 on a hot Dallas day. Drove 20 miles on the highway with AC on... Around 70mph average.

As soon as I took an exit and stopped at the light car stalls out. Temp gauge slightly above 175 which is normal.

Try to start it again never starts. Same thing happened a year ago. Exact same symptoms. Last time got it towed and my shop replaced spark plugs etc but the issue still persists.

Any leads on what this might be?

Update :The car sat for about 40 mins and cooled down. I was able to push the gas pedal all the way to the floor and it started up.

Same story last time as well. Started by the time the tow truck arrived... About 45 mins

Is it the injection pump? Fuel pump?

might be the ignition coil ....

A similar issue two weeks ago. Driving the car around town running errands. Stopped at a bank to make a deposit to the M-100 Group account. Returned to the car, started as usual but as I pulled into the lane in the parking lot, it just stopped. I have Pertronix installed. These have failed in hot weather before. I have spent two weeks testing and substituting ignition parts with no success. As a last resort, I replaced the coil with an old one on the shelf for 15 years. BINGO! I have never had a coil fail like this, suddenly. I guess it can happen.

Thx folks. What is the theory between hot weather and ignition coil failure? The car does start when it cools off so basically a bad ignition coil stops working when hot and starts again when not?

Could you telle me the last 4 numbers of the Vin for our Registery ???

Heat does expand materials. If there is s broken connection it can loose contact so functioning is underbroken ...

Sometimes Oil is pushed out and you can feel the oil on top ....

Last 4 is 4572

Is already in our registery ... Thank you

1st owner Mr Robert E Wood .... 181 hellbeige with 242 maroon leather ;-)

Cool.

Car was restored by Michael Morris about 5-6 years ago. Michael did a great job on this and this was my first Mercedes ever.

This car will always be special to me.

So did you identify the problem ?

Apart from the ignition coil, a usual suspect is the ignition condensator.

To help troubleshooting I would recommend:

1) an ignition dwell tester.

2) an ignition stroboscope lamp.

With (1) you can verify that the points and the condensator are working well together.

The total dwell angle should be 36 degrees at all times, all temperatures. (18 degrees for individual point unit)

With (2) you can verify that each spark lead gets the high voltage impulse towards each spark plug.

My apologies if I am writing about obvious things, but I am doing so because I know it is easy to forget about basic details when working with these fantastic cars :)

109.018.12 1968 Bronze Braun (M100 in good shape)

126.039.1A 1988 Dunkelblau (M117 so a bit slower)

+ A few other MBs used for daily transport

Ah, one more point: I may now have understood what Filip wrote earlier.

The ignition distributor needs to be lubricated regularly but sparsely. Off my head I cannot remember the amount of lubricant at each service interval, maybe Filip can tell.

In case the lubrication is ample, oil may pertrude up into the points compartment, this would occur increasingly with increasing temperature.

Of course the points have to be clean, you will need to check that there is absolutely no oil on them and, if so, clean them carefully.

109.018.12 1968 Bronze Braun (M100 in good shape)

126.039.1A 1988 Dunkelblau (M117 so a bit slower)

+ A few other MBs used for daily transport

Back to the coil: the coil that failed was installed about 2006. The car has been back and forth to the East Coast 3 or more times with that same coil. Returning from our Wisconsin meeting in August, there was a heat wave through the Midwest. In Utah, I was caught in a traffic jam in 106*F heat for nearly an hour at higher elevation near Park City. That coil did not fail then. I guess it was just old.