I cannot say enough on this. I had had the all important tappet adjustment done on my '85 300SD about 2.5 years agoand about 10K on the clock. I had driven the vehicle since summerY2K, and had had zero issues as a result of valve clearance. Then I had a routine valve adjustmentdone by a reputable MB mechanic. Then 10K on the clock goes by, and I get this intermittant skip when operating cold.It would shake the pudding out of you as an occupant of the car.

This condition worsened, as I tried to contact the same MB mechanic that did the last tappet adjustment, and gotbacklog times of 3 months or more from him. As for my queries and descriptions of the skippingwhich was getting steadily and alarmingly worse!he would only say that it was likely injector related, and that he would need to analyse all my injectors.

Meanwhile I had loosened the injector lines one at a time to zero in the skip as being on cylinder #1.

And in the meantime I had observed that the car would skip at idle when cold, run smooth at idle when warmed up, but start to skip once again after a hard pull, and a stop at a traffic light. It got to be embarassing with other drivers yelling at me and pinching their noses.

Again: my normal MB mechanic was booked ahead 3 months!

I found "Diesel Giant"...an organisation that most of you likely have seen, and they sent me a kit of two wrenches and a rocker cover gasket for doing what needs to be done. I found that all the tappets were within specsexcept for the frontmost tappetto wit exhaust on #1. It was the very dickens to work with. But I finally managed to develop the necessary clearance after having found it with less than no clearance at all.

What the heck is up with all of that? Especially after I had had the clearance done after about 50K of operationwith no complaint, and the mechanic saying that he found it unbelievable that I had gone that long without problems. Then he adjusts the clearances, and then well within 10K this one tappet is off by a country mile.

I have fixed the problem.

But the question still remains: WTF is up with this?

 

Congratulations on your valve adjustment. Valve adjustments are one of the things you have to do yourself. I can't even get people here to install a tire on a new wheel without wrecking it, much less trust them withsomething as delicate as a valve adjustment.
If the problem had been allowed to continue, it could have eventually burned the edgeofthe valve and seat and resulted in head-work. Good save.

Blue