Does anyone do that? How much should i add? will it hurt anything?

Why? If your using a modern new oil, you don't need any oil additives. The oils are engineered with everything you need, so why chance ruining a good oil?

Why? If your using a modern new oil, you don't need any oil additives. The oils are engineered with everything you need, so why chance ruining a good oil?
x2. Just change your oil with less miles if you are worried about the oil going bad, breaking down, or getting dirty, or whatever...

I've heard of Sea Foam for gasoline additive; I didn't realize they had a diesel-engine-oil additive.

In general, I'd steer well clear of an oil additive. The ONLY exception is ARX, but that's a personal choice based upon my docummented success over on BITOG.

It is mostly known as a fuel additive for diesel and gas engines, but it can be used for oil,gas,diesel fuel additives. Some people even run it through their intake and vacuum lines. But i would never run it through the vacuum lines!

It is mostly known as a fuel additive for diesel and gas engines, but it can be used for oil,gas,diesel fuel additives. Some people even run it through their intake and vacuum lines. But i would never run it through the vacuum lines!

IIRC, it is a solvent cleaner so should only be used as a flush in oil not additive. I put it in my Camry's vacuum lines to clean the emission system (EGR, VSV, etc.). It does the job. I would not put it in diesel fuel though, since it is naphta and it is similar characteristics as alcohol.

I agreed with DNewton, to clean engine, used Auto-RX (ARX). It takes few thousand miles and did the job to clean the ring pack.

It would not be used as an additive just a flush to clean some of the crap out of the engine, I would change it when done. I use shell rotella T and i change my oil every 4,000 miles.