I am sure this was discussed before but, I could not find anything in detail. What has everyone's experience been with oil consumption ? I have a 02 Chevy 2500HD DM/A 4x4 CC. My dealer tells me using 2qts per oil change at 3k miles is within normal limits. I use Mobil-1 Synthetic Delvac 5/40w. That seems kind of high for synthetic oil to burn that much in a short time. I have read of fleets using this oil up to 100k oil changes with little or no trouble. Some are using the Mobil or other synthetic for extended drains with just changing the oil filter(s) in between to keep it clean.

Diesels take forever to break in simply due to the lubricating qualities of the fuel itself. It is not recommended that synthetic oil be used during break in because it lubricates so well that it may take forever for the rings to seat. I would switch to plain old dino oil for two or three oil changes to allow everything to seat then you can switch back. Things should improve with time as this is normal during break in and in smaller amounts later. Either that or your PCV valve may be cracked. This would be minor and is unlikely. 2 qts does seem to be a little extra for 3000 miles but it should improve. Maybe Eric or one of the other techs will chime in with the norm. I have 56K and my oil comsumption reduces at each oil change. Now about 1/2 qt. Hope this helps. I wouldn't worry too much about it at this point.

My truck currently has 18k miles on it. I used Chevron Delo 400 for the first 12k miles. It used to be about 1/2 quart low after 3k miles.


At 12k miles I switched to Mobil Delvac 1. The current oil has 6k miles on it and at this time, no oil has been used. Most of this mileage is pulling trailers, either a travel trailer or PWC trailer.


I would imagine that each truck is unique. Edited by: OC_DMAX

For whatever reason, mine used almost 3 quarts between changes this time (5100 miles). Running Delo 400. 14,430 miles on the truck.

I have an 01 Max with 90,000 on it. I use an Amsoil Additional bypass filter with Mobil Delvac and currently have 9000 miles since last LOF. Used 1.5 Qts. in 9000 miles.

Thanks for the responses. I guess it sounds like this time the dealer is telling the truth for the most part this time since some vehicles are using just below & a little above the GM standard of consumption for the DMAX. I used Delo till 13000 miles then changed to the Mobil-1 Delvac. I am at 23k now. Does anyone think I should change back now ? The Dealer said they do not recommend any synthetic for the DMAX engineor trans & they do not carry it there. I told him I have been using it for years on my gas vehicles in the engine,trans & diffs with no problems.To me it sounds like if we (the dealer) do not carry it you are causing your own problems by not coming here to get your fluids changed by us with the bulk non synthetic lubricants. thanks for the responses.

It is an old myth about break in time and what type of oil. Older engines were not built as tight, so a thicker oil was needed. However the tight tolerances of todays engines can use any oil that meets that engines specs from day one.


My last three trucks had synthetic oil from within 500 miles of being new. two gas engines and now this diesel. 273,000 miles, 220,000 miles and now 59,000 miles and never a single engine related problem. the 97 with 220,000 miles never had so much as the spark plugs changed until just over 183,000 miles. And when I changed them there was no difference in power or fuel mileage.


Many of the high priced cars and trucks today have synthetic oil from the factory. And some of these have diesel engines.


I use nothing but Mobil 1. I did try Amsoil in this truck once for one oil change and miles per gallon dropped like a rock. It was the first change. I know it had nothing to do with break in because the tank before and the tank after got nearly identical mileage.


I do have amsoil dual by pass oil filter setup, but most of their things seem to be over priced for what you get.

I switched my Dmax to Delvac 1 before it hit 500 miles. It now has 50K.

I change the oil at 7500 mile intervals, which is about where the light comes on. Always Delvac 1. I figure if I'm gonna use that good oil, I can at least run it the full recommended distance between changes.

The truck has never used a measurable amount of oil. I've never added oil between changes, and when I go to change it, it always shows full, just like it was 7500 miles prior when I filled it up.

I love my Duramax ;)Edited by: ZFMax

75,000 km and no measurable oil consumption between changes.

Just had my oil changed with a little over 7K on the oil (65K on the truck). It was less than a half quart low with none added during the 7K miles.

I have 110,000 km, I change every 10,000-15,000km. I use cheap wal-mart tech2000 15-40oil in the summer and Delvac 1 5-40 in the winter. I have had no measurable oil consomption between the changes so far beside my recent PCV valve problem where I took about 20 quarts!

All my oil analysis where good. Most of then say that my oil still have 50% to go but I wouldn't fee good changing every 25,000 km.