I've really been enjoying reading all of your posts on oil, and appreciate all of the knowledge you have on synthetics, and taking the time to share it with us. Keep up the good work.
What brand of synthetic do you plan on using next?
Well, I have quite some Mobil 1 Tri-Synthetic 10W-30 left in my garage. I never paid over $4/qt on any synthetic oil. The Castrol Syntec and Mobil 1 Tri-Synthetic I have been using are the 5-qt jug variety from Wal-Mart, always, for less than $4/qt.
I will take a rest from Mobil 1 for now.
If I were going out tomorrow to buy some synthetic oil for the gasoline engines, I would buy the Havoline line of Synthetic oil. Normally it is only available in 5W-30 and 10W-30 viscosities, but they also have a 5W-40. AutoZones' regular price is $3.27/qt. Some store managers are willing to order for customers for the 5W-40. I talked to mine and he said if I buy at least 4 cases (24 qts, he can order). You can see the specs at
Very impressive specs. It out-specs Mobil 1 SuperSyn in every number I have listed (I use 10W-30).
If I were going out tomorrow to buy some synthetic oil for the diesel engines, I would buy the Chevron Delo Synthetic 5W-40. It is only available from Chevron distributors and some truck stops. The price is around $13 per gallon. You can see the specs at
I am wiling to try all sorts of oils but I always read the specs. For example, today I bought some Quaker State Higher Mileage 10W-30 at Menards for $1.69/qt (sale priced) with a $1/qt rebate so it will be $0.69/qt plus postage and envelope. I will first try it in the 1991 300E in the Michigan winter. These oils are more viscous than the typical 10W-30 (it is between 10W-30 and 10W-40) and has an extra anti-wear and seal conditioning additive package.