Mixing M1 5w40 TSUV with RTS 5w40

Messages
12
Location
NoVa
Since M1 5w40 TSUV isn't available I switched to RTS 5w40. I still have a quart of M1 left. I've never mixed oils before, but didn't want to waste the M1 - is there any problem if I use the M1 for top ups even though I used RTS for my last oil change?
 
Messages
13,228
Location
1/2 hr N.E. of Detroit
What is RTS? If it's Rotella, then you mixing add-packs from two different companies - which can shorten base oil life & additive life because one company may have an additive the other one doesn't -- as a result, that additive only becomes one-half effective when mixed with another base oil. Sounds complicated?... well the way I worded it even has me confused. [LOL!] [LOL!]
 

JAG

Messages
5,320
Location
Fredericksburg, VA
Do you have a lawn mower? If so, you know what to do with it. I wouldn't mix the two oils and would rather be out of $5 if I had no other use for it and couldn't sell it.
 
Messages
5,722
Location
Charlotte, NC
Go ahead, mix it, you'll never know the difference. I run RTS in my 89 turbo Caravan. When I change oil, instead of measuring out a fifth quart of RTS, I use whatever is available, sometimes 15/40 rotella, or ST, or 10/30 Formula Shell. I think on the next change I'll try M1 5/30. Maybe add a shot of VSOT and run it for 2 years. [Big Grin] [Big Grin]
 
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