top up oil

[buck91]

So I plan to use 5qts of PP 5w20 at the next oil change for my truck. Problem is that it takes 7-8qts total (spec is 7.7). I have Plenty of QSUD stocked to top the fill with. I know it Won't cause any problems but are these as similar as they sound? picked the PP up for a steal but could use it to top up instead or in the cars next oci for further cleansing.

In other words are PP and QSUD very similar with compatible add packs or should I just got with straight QSUD?

 

[CELICA_XX]

All oil is "compatible" and no harm will be done

I try not to mix oils, but that's just personal preference.

 

[WiskyBadger]

I would use the QSUD since you have so much of itand top off with PP. Mixing is fine.

 

[bigt61]

I would use the QSUD since you have so much of it. I avoid mixing unless I'm adding some to top off in the middle of an OCI. Use up what you have, go to PP later.

 

[ARCOgraphite]

Visible chemistry from PQIA table show the two oils to be indistinguishable (at least in 5w30 flavor)

Invisible chemistry - WK ??? I say mix away

 

[Garak]

If I were forced to mix, something like PP with QSUD or PYB with QSGB would be the least objectionable to me. As ARCO said, at least in the PQIA VOAs, they're virtually indistinguishable.

 

[sicko]

Originally Posted By: ARCOgraphite
Visible chemistry from PQIA table show the two oils to be indistinguishable (at least in 5w30 flavor)



Exactly what I was going to say. Mix with confidence, shouldn't be an issue at all.

 

[MuzzleFlash40]

I picked up a bunch of Napa synthetic when it was on sale for 3.49 a quart. This what i'll be using for top off oil for a while.

 

[ARCOgraphite]

Then you'll have a schaeffer-esque frankenbrew.