I have some general questions about car engine oil?

1) How often should I change synthetic oil? I have heard 3k miles, I have heard 10k miles. Can I get away with 10k without doing damage?





2) What is the difference between oils of different weight?





3) I use 5W-40. What do those numbers and letters designate? Can I use 5W-30 without doing damage to my car?





Thanks in advance!I have some general questions about car engine oil?
1) you change synthetic oil exactly the same frequency as conventional oil. Synthetic is best for extreme cold situations, such as Fairbanks, AK in the winter, because synthetics have much better cold-flow characteristics than conventional oil. The oil is not what ';wears out,'; but rather than additives, which are in the oil to keep your engine clean and free of corrosion (this is why you can find ';recycled'; oils such as Tech2000 or SuperTech on the shelves of many stores, they have simply cleaned the oil and put additives back in). The ';3,000 miles'; number is a holdover from 20 or 30 years ago. Both lubrication engineering and automotive engineering have made leaps and bounds since then. If your car is out of warranty, I would still recommend changing your oil every 5,000 miles, for two reasons: 1) your engine is well ';broken in'; by the time your warranty is out, and 2) it is an easy number to remember, no window sticker should ever be needed. A bonus to changing your oil every 5,000 miles is it is when you should be rotating your tires, so you can get it all done at the same time. BUT...if your car is still under warranty, then the only number that matters is manufacturer recommendation, which nowadays can be anywhere from 5,000 to 10,000 miles. Do not second-guess either the engineers or the lawyers. Most new cars have oil monitoring sensors, so you should simply change the oil when the car says it needs changed (kind of like a newborn).





2) and most of 3) Larger numbers mean higher viscosity; the W means the ';winterized'; weight, which nowadays has little to do with winter, and mostly to do with cold engine startup characteristics. Note the ';winterized'; characteristic of the oil is entirely a chemical additive which allows a thicker oil to perform as if it were a thinner oil. Nowadays all manufacturers recommend 5w30 or 5w20. Older cars (20+ years) recommended 10w30 or 5w30 for winter driving, and 10w40 or 20w50 for summer. The old belief was thicker oil protected better, while current modeling has shown the thinner oils protect as well as thicker oils, and, more importantly, begin protecting the engine sooner. Over 90% of the wear in your engine happens while the engine is cold, and the thinner oils can reach all parts of the engine much faster than thick oils. Next, the API ratings, now up to SM. These describe the oil additives, and how ';advanced'; the oil additives are. Different manufacturers may use different chemicals to achieve the same results, which is why it is recommended that you don't mix different brands. This is less of a problem nowadays, because the additive tests are so precise that there isn't a lot of different chemicals out there that will meet the SM tests...but the advice is still good.





3) What weight does your car manual recommend? 5w40 is actually a diesel oil (instead of / in addition to SM, they will have a CJ rating) -- it is still fine for gas engines, but has additional additives for diesel engines. Conventional diesel oil is 15w40, the synthetics are 5w40...if you happen to care. Since you are already using a 5w, I'd either stick to 5w40, or switch to 5w30 -- unless you have a recent model Ford, Honda, or Chrysler, in which case you ought to be using 5w20.I have some general questions about car engine oil?
Hello,


What vehicle are you driving?You should change your oil every 3000 miles.Do not go 10,000 miles, you will damage you motor! The owners Manuel will tell you what type of oil wt to use.Weather is the key on what type of oil to use.Like Temperature 32 and lower you need a light wt oil 5w-30 SAE or 10w-30.Remember It all matters what type of vehicle and engine you are driving.The WT on the oil is (Light 5W20 to 10W30) (medium 5W30 to 10W40 or (heavy5W40 to 10W50)


Synthetic oil is ok on some vehicle and bad for others.This oil is very very light Wt.I will not use this oil on my truck because its to light.


If you don't have a owners manuel call the dealer, Make of your vehicle


and they will tell you if you can use Synthetic oil for your engine.


I hope This Help Pete