Oil getting dirty between oil changes

jem-c70 · Post by **jem-c70** » 14 Nov 2011, 16:33

I've got 84k on the odometer, change oil every 5k with Mobil 1 and the oil gets dirtyier between changes.
Theres 4k on this change and the oil is dark brown, 20k miles back the oil stayed clean between changes.
Whats happing ? Carbon build up, time for a Seafoam treatment ?
Any suggestions ?
Thanks

Post by **Pauloil** » 14 Nov 2011, 16:43

I don't think you can tell by looking. need oil analysis. or put some bet. 2 fingers and see how it feels. with M1 you are fine for 5K-10K. read up on bobistheoilguy.com

FCPEURO · Post by **FCPEURO** » 14 Nov 2011, 17:07

+1

the only way to know for sure is to have the oil looked at. If you want to look into something in the mean time, check the PCV system.

linuxsuperuser · Post by **linuxsuperuser** » 15 Nov 2011, 08:02

Switched mine around 120,000+ plus, same thing with mobile1. M1 kind of in itself acts like a solvent and slowly dissolves built up deposits. The first time I used it, my car's oil was getting really black around 1000 miles and consumed a quart for the remainder of the interval.

Now, I can easily run past 5000 miles and it's still golden colored.

Stay Away from engine flushes or sea foam - the mobile1 is only doing its job hopefully within the next 2-3 changes it should begin to clear up.

Post by **jblackburn** » 15 Nov 2011, 09:44

^^^Same story for me. It starts getting dirty after 3-4000, but up until that point it still looks brand new. But it's MUCH less black than it ever was running on conventional oil.

Post by **rspi** » 15 Nov 2011, 18:13

I hate to thread jack but I have heard that Royal Purple is the best and stays clean the entire time. Other than that, I like to use 10w30 full synthetic in the winter and 10w40 full synthetic in the summer because it will get over 100 degrees 30 to 45 days in the summer. My issue is that most companies, I usually use Castrol, has stopped making 10w40 in full synthetic and I believe they have recently stopped making 10w30. I see a lot of 5w30. The only 10w40 I could find what the Mobile 1 High Mileage synthetic.

Is it ok to use 5w30 or 0w30?

Well, I just checked their website and they show that they still make many grades, not sure where I can find it.

http://www.castrol.com/castrol/sectiong ... Id=7067038

bguzz · Post by **bguzz** » 15 Nov 2011, 19:53

you actually want the oil to get dirty between changes...that tells you that its taking in the combustion leftovers and suspending them in the oil. If it is staying clean the entire time, then it is building up combustion leftovers in the engine. Get rid of the Royal Purple...I always thought that was more of a gimmick oil (think Slick50).

Post by **FlyingVolvo** » 15 Nov 2011, 21:16

Royal Purple is a great oil, but you can definitely get something that works the same for way less money. Any big name brand will do fine.

0W-30 works fine. 0W-40 works fine. As do 5W-30, 10W-30, 5W-40, and 10W-40. Preference to 0W and 5W for very cold starts. Different oils are suited for different engines/climates etc... so there is no one "best oil".