06 Subaru 2.5i RL5w30 5,000mi Would you go 10,000?

[Ty Williams]

This is from a 2006 Subaru Impreza 2.5i (which is the SOHC non-turbo motor). Around 5,000mi on this OCI with 1qt of makeup oil total over the OCI. No mechanical problems with the car. It's her daily driver with a 30 minute (at minimum, traffic makes it longer) commute each way every day. From the UOA below, is there any reason you wouldn't try to go for a 10,000mi OCI next and then get a UOA at the end of that?

 

[rslifkin]

Without knowing the TBN of the oil, I'd be hesitant to make a decision to push it farther based on that UOA.

 

[tomcat27]

given that its RL, should be no problem. of course, it wouldn't hurt to run a TBN on one of your (longer) UOA's

 

[Ty Williams]

Yeah, I thought I told her to check the box for TBN but I either forgot or she didn't listen. We've just discussed the need to do it next time.

 

[The motor guy]

how many miles does she drive to work? It takes me 30 minutes to get to work too but it's only a 10 mile drive. Im just trying to figure out how much time you have hour wise on the oil.

 

[Ty Williams]

It's 18.8mi each way. As I said, it takes a minimum of 30 minutes each way and traffic often pushes it up above an hour each way.

 

[Boss302fan]

That is a lot of moly...

 

[Ty Williams]

1) it's RL, it has a lot of moly
2) It's Blackstone, most of those numbers are for entertainment value only

 

[tinmanSC]

Looks like you changed oils at 55K. What did you change from?

 

[Ty Williams]

I'm not entirely sure, honestly. I know she was using Pennzoil Platinum for a while but I'm not sure if that was immediately before the RL or a while ago.

 

[The motor guy]

Looks like you would have around 250 hrs on the oil if it took her an hour each way every time she drives to work. I don't see why you couldn't do 5000-6000 mile oil changes. I wouldn't go any further without a tbn. The good news is that the car get nice and warmed up to burn off any fuel/moisture in the oil so they should help you be able to extend oil changes. I just wouldn't do 10,000 miles without the tbn.

 

[ARCOgraphite]

If tha Ca # are correct its a long drain oil if there ever is one. But you cant Jump from 5k to a 10k oci - esp without any TAN/TBN. When the oil goes DOWN it goes FAST at end of life. The Factory std service interval on on my wife's 09 subaru engine is 7500 miles with plain old dino. Ive been doing that with NO problems (other than finding thick -but not too thick- enough oil for summer).

 

[Eddie]

I'm cuorous as to why the consumption jumped from zero to one quart usage in the same oil usage interval. Thas may suggest another issue than TBN being low..

 

[Ty Williams]

RE: The jump in oil consumption...

Subarus just do that. Consumption anywhere between 0 and 2 quarts on a 5k OCI is just random variation for them. It all depends on how much the car sat vs ran vs ran at high RPM.

 

[Doug Hillary]

Hi,
Ty-Williams - It is good to see you being consistent and establishing a trend base for this vehicle. It all looks good!

To answer your question: Would you go to 10,000? I acn only offer this

I had this engine in an Outback that I sold with around 160kkms (100k miles) on it - this is its story:

Average OCI - 15000kms (9300 miles)

Oil types:
M1 0W-40 (for 32kkms)
M1 01W-30 (for 32kkms)
Delvac 1 5W-40 (for balance)

All the above oils performed about the same and my UOAs were consistent like yours over the car's life with me

Avg oil use: 1ltr 7kkms (4.5k miles) and never worsened until sale point

Typically these engines are not demanding on lubricants so a popular synthetic of the correct viscosity (and spec) will survive very well

A TBN and PQ Index No is handy to have when trending - a TAN is not really needed on petrol engines

I hope this helps

 

[chevrofreak]

Originally Posted By: Ty Williams
I'm not entirely sure, honestly. I know she was using Pennzoil Platinum for a while but I'm not sure if that was immediately before the RL or a while ago.


First two look like Pennzoil Platinum, and the next two look like Rotella T6 5w-40.

 

[Ty Williams]

Hmm, I'm sure it wasn't the T6, the timing wasn't right. That oil JUST showed up around here. I think there was a possibility she was using the old Rotella 5w30 at one point. I'll have to ask.

 

[steve20]

10K on the RL without blinking an eye
Bet the wear number will be within 1 or 2 ppm of each other after 10K miles-except the Fe which would go up to 14


Steve

 

[Santo Fontana]

Looks like insolubles will be your limiting factor. Try changing the filter@ 5k and go to 7.5k. Then to 10 k hopefully.

 

[chevrofreak]

Originally Posted By: Ty Williams
Hmm, I'm sure it wasn't the T6, the timing wasn't right. That oil JUST showed up around here. I think there was a possibility she was using the old Rotella 5w30 at one point. I'll have to ask.


Could be the pre-T6 CJ4 stuff.