Switching around among PAO synthetics

[pbm]

I know the conventional wisdom is that when first using M1, Amsoil etc..keep the first OCI reasonable because of the cleaning effect. How about when using a different PAO after using M1?
In other words if I use Amsoil or RP after a few OCI's of M1 can I still extend the OCI?

 

[blupupher]

I've never heard to keep the first OCI short when switching (other than to get a used oil analysis before real extended intervals).
I would just say keep doing what your doing when you switch (per used oil analysis ideally).

 

[Al]

PAO's don't clean up that much.

 

[pbm]

quote:

---

Originally posted by blupupher:
I've never heard to keep the first OCI short when switching (other than to get a used oil analysis before real extended intervals).
I would just say keep doing what your doing when you switch (per used oil analysis ideally).

---

I said 'reasonable' not 'short'. What I meant was
that I wouldn't jump right into a 8 or 10K OCI with syn. after running the first 45K on dino and blends. When I first used M1 (5w30) I went 'only' 5.5K. The current fill of M1 (0w20) I plan on draining at 6.5K (maybe 7K max.). If I decide to use RP or Amsoil (5w30) for the next OCI I wouldn't have any problem going 6 or 7K because of differing chemistries? or would I?
Vehicle is an 01' Accord 4 cyl.

 

[Iain]

blupupher wrote:

quote:

---

I've never heard to keep the first OCI short when switching (other than to get a used oil analysis before real extended intervals).

---

Exxon Mobil Corporation recommend < 3K OCI for initial use of Mobil 1.


http://www.mobil1.com/USA-English/M...tic_Motor_Oil_in_Higher_Mileage_Vehicles.aspx

Question:
Switching to Synthetic Oil in Higher Mileage Vehicles
Does switching from a petroleum-based oil to a fully synthetic oil on a higher mileage vehicle (75,000 miles) have any harmful effects? I've heard that the synthetic oil, because it is cleaner, may actually loosen some of the build-up from petroleum oil and has the potential of clogging the pump. Is this true or does one simply need to change the filter more frequently for the first few thousand miles after switching? Thanks
-- Michael Ritzke, Appleton, WI

Answer:
When switching to Mobil 1 in higher mileage vehicles, we recommend an initial short (2,000 to 3,000 miles) oil change, both oil and filter. This will allow Mobil 1 to clean some of the engine deposits that have accumulated over time. Following this initial short oil change, continue with your normal oil change interval.