Is it safe to mix synthetic oil and conventional??

I had mostly conv oil in my engine, but added a lil of teh synthetic. Will it be okay??Is it safe to mix synthetic oil and conventional??
Robsteriark is correct. Synthetic and natural oils are completely compatible with each other. There are no chemical incompatibility issues. It's no more harmful than mixing Evian water with tap water.





There is little practical downside to mixing natural oil and synthetic, either. the only issue is loss of a small fraction of a synthetic oil's protective quality, in proportion to the amount it is diluted with natural oil.





Natural oils have inferior viscosity index (flow less readily when cold, thin more -- hold their lubrication film less durably -- and lose their lighter fractions from evaporation more readily when hot), but as long as you use the recommended grade and viscosity, and change oil according to the manufacturer's recommendations, they are okay in an emergency.





Synthetic oils are at there best in the worst conditions -- cold starts. When you shut your engine off, the oil is hot and thin, and most of it quickly drains into the crankcase.





After your car has been sitting for a few hours, that oil will have cooled and thickened. When you start the car, the oil that remained between moving parts has a tough job. There isn't much of it, and it's thicker than it was when the car was running, so it's harder for the oil pump to get it out of the crankcase and back where it's needed.





The first few revolutions of a cold engine stress that thin film immensely. In extreme conditions, if it's too thin, it gets scraped away and you have bare metal scraping against bare metal. Even if they do not, this is when the most wear occurs in an engine.





Natural oils are thicker when cold, and when they have been in the engine for a while they will have lost some of their lighter fractions -- the thinner oils that protect best when cold, from evaporation.





That's why synthetic oil protects better in a cold start.





There are chemicals that can be added to natural oils that extend their viscosity index, but every drop of an additive means less oil in a quart to protect your engine.





The differences are small, so adding one quart of natural oil to a crankcase full of synthetic just means instead of getting the full benefit of synthetic, you're getting about 80% of it.Is it safe to mix synthetic oil and conventional??
It's perfectly fine.





If you are ever curious what ';synthetic blend'; means on some bottles of oil, it is just a mixture more expensive higher quality synthetic oil and less expensive conventional oil.





Any synthetic oil produced in the past few years is completely compatible with conventional oil with no downsides. If you need additional proof, this information can be found on any of the major oil companies' websites.





Good luck!
Most oils sold retail are mixable /compatible. The racing oils, Castor bean racing oils are not sold retail and don't have SAE ratings for mix-ability. If you mixed SAE rated oils you shouldn't have a problem, Semi-Synthetic oil blends are this way to get the flow of synthetic and cushioning affect of conventional large molecule oils
ok so here is my opion form exprince... i drive a gmc sonma with the 4.8 i recently lent it out to my grandfather and i run strictly synthetic in all my cars and wut he did was put conventional oil in it and it blew the engine if u add only a lil it prob will be okay but what happens is when the syn.. and the conv..... oils mix they have a chemical reaction and if the chemcial reaction is lagre enough it WILL SEIZE YOUR ENGINE ....so you might want to think twice about it so to say the least when they are mixed it is bad and can cause your engine to seize trust me
No problem; it's completely compatible with mineral oil. You now have your own home-brew semi-synthetic oil blend ;-)
It usually is not really a good idea to mix conventional oil and synthetic oil becasue it can potentially damage your engine.
Why would you do that? I think you should use one or the other, but it doesn't make sense to mix it up.
DANGER! DO NOT MIX!