I just got a 2001 GMC Sierra with an 8.1 in it. The motor only has about 85,000 miles on it. He has always run synthetic oil in it and change it every 3000-4000 miles. I'm wondering if I could run into any issues if I start running Rotella T 15W-40 in it, instead of the synthetic oil? Thanx for any input.
Switching to convetional from synthetic
- Thread starter apstang50
- Start date
- Status
Nick1994
$100 site donor 2024
15w40 is quite a bit too thick for my tastes in Massachusetts.
I'd run T6 5w40.
I'd run T6 5w40.
+1 on switching to Rotella T6 instead
4WD
$50 site donor 2024
Are you looking to spend less ?... there are some 10w40 High Mileage oils ...
Rotella T5 10W-30?
The 8.1 (496) is stout, reliable engine.
4,000 miles & drain on synthetic is far too often. I'd run a conventional in the "big block" to 5,000-6,000 easily and more if warm weather and highway miles. A 454 can usually run synthetic for 10,000 easily. There's a member here who has the same oil (I think mobil 1) in his 454 for 5 years now.
4,000 miles & drain on synthetic is far too often. I'd run a conventional in the "big block" to 5,000-6,000 easily and more if warm weather and highway miles. A 454 can usually run synthetic for 10,000 easily. There's a member here who has the same oil (I think mobil 1) in his 454 for 5 years now.
Last edited:
Originally Posted By: apstang50
I'm wondering if I could run into any issues if I start running Rotella T 15W-40 in it, instead of the synthetic oil? Thanx for any input.
This dual rated HDEO minerals would probably be good for (up to) 6K or more OCI..
I'm wondering if I could run into any issues if I start running Rotella T 15W-40 in it, instead of the synthetic oil? Thanx for any input.
This dual rated HDEO minerals would probably be good for (up to) 6K or more OCI..
OK to use Dino oil. But I would run 10w30
So far you have three different viscosity recommendations. Just switch to the conventional weight that your owners manual calls for. If you don't have one, they are easy to research and obtain.
There are no "conventional" ILSAC oils. The Mobil 1 is not a synthetic but a blend of largely grp _III refined petro oil.
C-j 15w-40 is the wrong stuff.
If I had that engine Id likely source a ACEA A3 oil. Motul X max 5W30 to start. Mobil 1 0w40 or Castrol 5w40 MB299.5x spec oil would be fine I sure aT A COST SAVINGS. These ACEA 40's are marginal 30's by design.
C-j 15w-40 is the wrong stuff.
If I had that engine Id likely source a ACEA A3 oil. Motul X max 5W30 to start. Mobil 1 0w40 or Castrol 5w40 MB299.5x spec oil would be fine I sure aT A COST SAVINGS. These ACEA 40's are marginal 30's by design.
That 8.1 Vortec has a roller cam if i'm correct, so it doesn't need any high zinc oils.
15W-40 rotella would be a bit too thick, i'd rather use Rotella T6 5W-40 or T5 10W-30.
15W-40 rotella would be a bit too thick, i'd rather use Rotella T6 5W-40 or T5 10W-30.
- Status
Similar threads
