So I put some QS "SUPREME" HD-40 in my 97' Jeep 2dr Cherokee ex county vehicle/parts and scrap hauler. Put 2quarts of it, 2quarts of Pennzoil 20w20 non detergent and rest was PYB SN 10w30. Left the TG-16 on for another 5,000 miles or so as it has 4,800 miles on it now. I have around 11 quarts of the QS "supreme" HD-40 stuff and 8 quarts of the Pennzoil 20w20; and no I doubt it will hurt anything.