DaveGee

My car has a relatively fresh oil change using an unknown brand of synthetic 5W-40 oil. Which is the lesser of "evils" here:

1. OK to top off the oil using any brand of synthetic 5W-40.

or

2. Only top off the oil using only the same brand oil already in the car - even if 5W-30 or 0W-40 are the only weights available.

Opinions?

DaveGee

terbiumactivated

The level of the oil obviously is the critical component in your question, I can't see any issue with topping it off with whatever approved brand you like. I'll say this, given the other thread and the costs for oil changes, everyone should buy a catch pan, recycle storage container, Porsche cartridge tool, metric allen set and a durametric. These items pay for themselves in a very short time period. Pelican sells mahle filters for around 20 beans shipped and Wallmart has Mobil one for a great price. Can be done way under 100 clams, the dealers are raping you guys.

DBH

Probably a good idea to stay with the same viscosity and you cannot go wrong with Mobil 1 that's easily available.

okie981

Topping off with a relatively small amount of oil percentage-wise of the total fill quantity is very unlikely to cause any detrimental effects. Mixing too much oil of one brand or type with another may cause "additive clash" and should be avoided unless no other option is available.

See slide 14 of this presentation for reference:

https://www.drivenracingoil.com/docs...cingOil101.pdf