hi, my engine is running rough, with intermittent kicks, and smoking, seems like oil burning.

valves have been adjust a couple times.
rack damper idle adjuster spring bolt has been changed and adjusted.
a few cans of diesel purge have been run, as well as startron.
each gave a small improvement but not complete fix.
there is injector knocking coming from 1st valve, 1st 2 injectors have been been tested for pressure and spray pattern.

compression tests and leak down tests have been done. it seems that there is a leak in the 1st valve, and the compression is lower on it than the other 4 valves.

basically it seems like most things have been ruled out, and the next step is a valve job.


has anyone paid a shop to do this? if so, how much?
i'm going to get a couple estimates, from my shop, and one that comes highly recommended, but i want to be able to gauge if they're over quoting.

also i'm a little worried that i'll end up spending the money on it and for whatever reason it wasn't the problem. based on the info i've given, would anyone have doubts?

thanks in advance,

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w123
1985 300D turbo sept 2015 - present
1985 300TD turbo oct 2023 - present
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