Diesel Oil


Senior Member
Fairbanks AK
I just recently purchased my first diesel pickup. It's an 82 6.2 1/2 ton with a 3 speed manual with overdrive (not the best tranny I found out, it went south this weekend). Anyway, I changed the oil on the truck right when I bought it. It was pretty black then, and I figured, it couldn't hurt, cuz who knows how long it had been. I've put about 1,000 miles on it since the change, and it's already as black as night again. Is this a normal trait with diesel engines? Should I be using a different oil, maybe a non detergient type? I don't think that's a good idea, since the junk that they detergient oil suspends in it would just be sitting in the engine somewhere else. This motor doesn't seem to have anything wrong with it. It runs great, starts right up every time, has pleanty of power, doesn't smoke too much, and gets me between 18 and 20 miles to the gallon (good info for all those gas mileage woes that I've been seeing on.) Anyhoo, info would be appreciated. Thanks guys.


2000 Club Member
I have a 98 with the 6.5td and I change the oile very 2500 mi, more often when plowing. I have put 200mi since the last oil change and it is already black, and it has done this since day one. I must be the soot from the diesel engine. I use rotella-t from shell. I can get it at BJ wholesale for 30$ and that gets me 6 gallons.<br>If this is your first gm diesel go to <br>www.62-65-dieselpage.com <br>It is by far the best site for info on gm diesel engines bar none.<br>Dino


Senior Member
Like said this is normal for all diesels. I run 20w50 in My tractor. also in most of the diesel vehicle I serviced. Even the bigger Diesels that I used to service were the same way. even with a 12 in piston the oil was always black in less than a minute.