If you use regular motor oil in your car, and then go synthetic do need to only use synthetic?

Answer 1

Yes, you should, because a mixture doesn't give you all the protection from heat and gumming up that a purely synthetic mixture does. The good qualities of a synthetic are watered down by mixing with conventional oil.

Answer 2

If You have been using regular motor oil for some time, and then want to switch to synthetic, YOu should first drain all of the old oil from the motor and to change the oil filter. Then You can put synthetic oil in the motor.

When the oil level drops down to the "low lewel" mark, You MUST NOT add regular oil, but only synthetic. If You want to switch back to the regular oil, repeat the described procedure of changing the oil and the filter.

In case that You have mistakenly mixed the two different oils (not two brands of a synthetic oil, but synthetic with regular), don't start the motor, but drain out all of the oil from the motor and then replace the filter. Chemical reaction between two different "species' " of oils can form either clogs in narrow channels, or to leave some of the motor parts dry, due to loss of lubricating properties of both types of oil.

However, You can use semi-synthetic oils and mix them with regular ones, in case of such need. Semi-synthetic oils are cheaper than synthetic, but have better lubrication properties than the regular oil.

Anyway, if You do not force Your motor to spin at high RPMs for a long time, regualr or semi-synthetic oils will do perfectly. Only in case that motor is overloaded for a significant time, You should use synthetic, for it's stability at high temperatures and in conditions of intensive friction, that occur at high RPMs.

Answer 3

The regular motor oil is different from the superior synthetic oil,
which is a high performance oil and having a very low grade of
5W/30 (very thin oil) compared to the former of 20W/50 (much
thicker oil). It is advisable not to mix the two types together.
However, you can use them one at a time, switching back and
forth every time you change your engine oil during the servicing of the car.
Depending on the type and condition of your car, it's best to
use synthetic oil for new cars of high performance. For used
or second-hand cars of more than 5-years old, use normal
motor oil of grades 15W/40 or 20W/50 which is good enough.
Two good brands of lubricating engine oil are Castrol and
Duckhams.

Answer 4

No, a motor has no memory. synthetic oils provide better lubrication, but only as long as you use them. The real problem with oil is the contaminants which accumulate in the oil, and both synthetic and natural oils accumulate the same amount of crud. That's why it's important to change your oil regularly, to get rid of the crud that has gotten into the crankcase. You can switch back to regular oil any time you please. Remember to change your oil and filter regularly, however, whichever oil you use, that's what makes the difference, getting rid of the grit.

Answer 5

No. Its just a rumour. Unless you mean to mix them both, in which case I don't recommend because mixing the two may deterioirate your gaskets and O-rings.

If you want to switch to synthetic, beware, a small pin hole in any of your gaskets turn into a major gusher because synthetic is much more viscuous (thinner, in a sense).

Answer 6

Yes! Once you change over you can not mix different types or even different brands of synthetic.
I keep a few cans of my brand in the car, so if need to top up I have the right oil with me.
I also buy my oil by the case and my filters can be bought in "6 paks".
BTW Even on a 700 mile trip I added very little, the Mobile syn oil I use, realy holds up.

Answer 7

Wives tale. Blended oils are regular oil (liquid dinosaurs) and synthetic. You CAN mix the two.

Answer 8

i've asked this question a few times in the past. i have mechanics that tell me, there wouldn't be any problems switching back and forth. and i have some that tells me that i shouldn't go back and forth. overall i came to a concusion, once sunthetic always synthetic. if you want to go back, you can always flush out your system...

Answer 9

No. You can switch back and forth or mix them.