Shop used Synthetic instead on Dino

[mark40]

We have a Subaru Outback that has always run on conventional and is at 83,000 miles. Today my wife took the car in for an oil change and the shop put in Mobil 1. The Mrs. asked for M-1 by mistake; our Toyota Matrix gets M-1 so she got em mixed up.

Way back when the Matrix was approaching 100,000 the mechanic recommended Synthetic, so is there any merit to this with the Outback approaching 100,000?

The last UOA with conventional was great- wear metals at or below normal and they commented that 5000 miles would be fine with conventional 5w30.

Anyhow do we have an issue here? Any implication to switching back to Conventional?
Reason I'm asking is I've seen some negative comments over the years about switching over from one to the other.

 

[SwampSurvivor]

Absolutely no issues running a synthetic oil at that mileage. And no issues between switching back and fourth.

 

[Quattro Pete]

Originally Posted By: mark40
Anyhow do we have an issue here? Any implication to switching back to Conventional?

I don't think you have anything to worry about.

 

[bigt61]

No problem going back, just don't be in any hurry to drain the M1 if you want to get your money's worth. Go at least 7500 miles or even 10,000 if you keep it topped off.

 

[UltrafanUK]

Originally Posted By: Quattro Pete
Originally Posted By: mark40
Anyhow do we have an issue here? Any implication to switching back to Conventional?

I don't think you have anything to worry about.


You can switch back and forth between a major brand Dino and M1 as often as you like, although if the 2 oils have very different Add packs, mostly in terms of the quantity of detergent/dispersants, it can result in a minor increase in the wear metals.

For example Castrol GTX 10w40 to Castrol Edge 0w40 (A3/B4) would be less than ideal, as the more basic forms of GTX don't have much Ca (Calcium based detergent) content as it uses Na (Sodium) based additive as a cheaper alternate. Edge uses Ca and Mg for a much longer lasting detergent/dispersant mix of Adds.
Suffice to say that the latter has a bad habit of attacking the anti wear layer (Mostly Zn based) of the former just after the oil is changed.

 

[Kuato]

Nothing to worry about, and a great opportunity to see how the UOA of the M1 looks at the same distance....maybe even leave it in when you take the sample...

 

[tig1]

Wear metals from UOAs doesn't mean much when comparing oils. In fact,IMO,the primary reason to do UOAs would be if you suspect oil contamination,such as coolant, dirt, or fuel.

 

[bbhero]

Right on tig1. That's the real purpose of a UOA and to check if it's still in proper viscosity range.

 

[daves87rs]

Will be just fine. Run it maybe a 1000 miles or so longer and enjoy....

 

[alarmguy]

No problem switching back and forth, its all just oil. Syn or Conv, made from the same thing, crude.
If you do regular scheduled oil changes according to manufacturers recommendation, conventional oil will perform just as good as synthetic. In general there is none better then the other.

 

[Kuato]

Originally Posted By: tig1
Wear metals from UOAs doesn't mean much when comparing oils. In fact,IMO,the primary reason to do UOAs would be if you suspect oil contamination,such as coolant, dirt, or fuel.


Not in the short term, no. That's why I suggested leaving it in when taking the sample - it's likely able to go much further than the dino.