How long would you trust QSUD for?

[Hollow]

Car: in signature.
Owner's manual interval: 7500 miles/7.5 months or 3750 miles/3.75 months severe conditions.
Miles/time on oil currently: 7000 miles/6 months.
Vehicle usage: Sporadic. 70/30 highway/city when used, but may sit for a week or more without being moved. Occasional short trips (3-5 miles) to grocery store.

I know the best answer is get a UOA...but that is $25 that is better spent on groceries or insurance right now. Funds are short for a grad student.

I know QSUD is a solid oil and the PureOne filter should still be ok, I'm just wondering if I'd be dumping it too at early at 7500 miles. Thoughts?

 

[dparm]

I think 7500 would be fine, but get a UOA to know for sure. You'll pay for the UOA once and that will eventually let you run every oil change longer. Pays for itself after a bit.

 

[bullwinkle]

QSUD is Dexos 1 certified, which should indicate up to a 10K OCI depending on conditions, but I agree with dparm-longer than 7500 means a UOA. I had this same problem with M1 AFE 0W30 in my wife's xB-I figured I could run 8-9K easily, but the oil was sheared & TBN depleted below 2 in only 7K. YMMV.

 

[ottotheclown]

5k why? Because then you will not have to worry about the oil. You can worry about other things like a.........

 

[bepperb]

I'd say 7500 and call it a day. You might be leaving a little on the table, but even if you find out 10,000 is safe you need four more OCI's to recoup the cost of the UOA. Outback is a fairly heavy car with AWD overhead and a relatively small engine (like my Highlander) so it's not the world's best candidate for ultra long OCI IMO.

 

[fdcg27]

NA Subarus look to be pretty easy on their oil, so 7500 on QSUD should be okay.
How much longer in your use is unknowable without more information on the how the oil is holding up in your use, thus a UOA.
Subaru recommended normal intervals of 7.5 months or 7.5 K on any API spec 5w30 current to the car's MY, but you'd be pushing it with some oils.
If you wanted to do a UOA, kits are available for much less than $25.00.
Check the Product Rebates, etc forum.
Amazon has recently offered prepaid Wix UOA kits at prices that would get you four of them for $25.00.

 

[zerosoma]

QSUD SN has a starting TBN of 9.2. That's a pretty solid oil, but I would say don't run it longer than 8k.

In fact now is a prime time to change it.

 

[GumbyJarvis]

Currently Using QSUD in my truck with a BOSCH filter, Ive gone 7.5k on it before, still came out lighter than most oils ive run.

EDIT: Ive gone 7.5k miles on it before with a BOSCH filter, so you shouldnt have issues with a P1

 

[hardcore302]

I am running it and I will go 6k, i run hard.