mixing oil brands?

[Yargk]

I bought a 325is with about 150000 miles on it. I had the oil changed and I knew that it burned a little oil, however I had neglected to put a couple quarts in the trunk as I do with all my other cars. So sure enough, 1500 miles after the change, the oil light comes on. I was next to a 76 station so I got some of their 20w50 oil and added a quart. The oil change was done with a brand called kendel (or similar name). Is it okay to add oil of a different brand when the same brand isn't available? Does it effect the oil's performance? Should I be worried that it got low enough for the light to go on?

[KC Ron Carter]

I have intermingled oils as needed for more than 40 years. I have even used nondetergent if no other is available.

I usually add a quart of ATF and drive the last fifty miles before and oil change with the 90% detergent ATF in the crankcase.

When you see an engine like this:



It is the overtemp cooling of the varishes and not the oil.

[BMW Boogie]

That oil level light coming on is just a signal for you to add a quart. I don't think you hurt anything.

Ok to add a different brand in a pinch. Try to stay within the manufacturer's viscosity specification. Even a diesel oil will work. You can use diesel oils in gasoline engines, but not vice-versa. If you use petroleum oil, make sure you change it every 3k with filter.

If the engine in your newly purchased car is caked with black sludge visible inside the valve cover oil fill opening, be very very careful. The former owner did not change the oil regularly enough to keep that engine clean. Sludge is a grinding compound! New oil will release & disperse the sludge into the oil & grind away the engine. I've got a close friend that lost his engine due to this. Wore out his main & connecting rod bearings till the engine started knocking. If you have sludge, buy a good engine flush such as Amsoil & install it in the old oil. Idle for 30 minutes then immediately flush. This will release the varnish & sludge into the old oil so that it will drain out with the old oil. Do not drive the car with the flush in it. Idle only! Sometimes you have to do it more than once to effectively clean the interior of your engine. Only after you flush, should you use new oil. Keep a watch on the oil color. As soon as it darkens, change your filter & add a quart. When the oil stays clean enough to last 2000 - 3000 miles, you will probably be safe.

If you go to a good synthetic such as Amsoil, Castrol Syntec, Mobil 1 or even a good high detergent diesel oil, a possible good side effect could be reduced oil consumption:

The piston ring grooves that loosely hold the rings are engineered that way so the rings can "bend down" as they go up the cylinder walls. As they go up in this "bent down" position, the outside upper corner creates an oil bead that seals the chamber for good compression & stops blow-by & oil consumption. If your lands are caked with carbon deposits, your rings can't bend down!

You can use a top-line high-detergent diesel oil to gradually disperse the carbon in those lands. Problem is that most diesel oils are too high a viscosity. I have used Amsoil synthetic oil at the factory recommended viscosity with great results. It may take 2-5000 miles to do it but it works if you have enough piston ring left. If the rings are worn out, thisa notta gonna work!

Good luck on your new purchase. Let me know if you have more questions. - Marvin