mixing motor oil brands

[hominid7]

quote:

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Originally posted by gogozy:
wonder what will happen with the oil left in the engine during oil change? shall i worry??

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If you dissasemble the engine at each oil change and thoroughly clean all internal parts with gasoline, then with naptha, and let air-dry overnight in an O2 chamber you shouldn't have any problems with that

Seriously though, if you really did want to get a complete and fresh oil change, after the engine oil drains, you can dump 1/4 qt of the new oil and let it run through the engine to help flush it out.

Another more expensive method would be the "double flush oil change". In other words. Change your oil. Run the engine 20 miles, and change it again.

I wouldnt worry too much though. At most there is approx 1/8 qt left in the engine. If you have a seperate oil cooler you may have as much as 1/2 qt, but if you change your oil often enough it wont hurt anything.

 

[Steve S]

What is the difference between the additive packages in motor oils of like use? Zinc is zinc,calcium is calcium etc. I don't understand additive clash.

 

[sxg6]

my thoughts exactly steve.

 

[mechtech]

The vast majority of oils mix just fine, with no problems evident.
I'd like to see some specific names and problems from the source of the warning.
I'm not saying it can't happen, though.
.

 

[blupupher]

Currently running 4 qts 10w-30 Valvoline AllClimate (SL) and 1.5 qts of 5w-30 Mobil 5000 in the wife's van for a Auto-Rx rinse phase and it has not blown up yet.
Next change will be 3 qts 5w-20 Mobil 5000, 1 qt 0w-20 Mobil 1 (SL), 1 qt 5w-20 PP, and 1 qt 5w-20 Maxlife dino.
I may do a UOA on it when I change it @ 6 months (4000-5000 miles) just to see how it has done.