Can I Return To Using Conventional Motor Oil After Using Synthetic Motor Oil?

16 Answers

Anonymous Profile
Anonymous answered
It makes no difference if you switch back and forth. Anyone saying so is spreading a myth that has existed since synthetics were first made. The truth is that at the core they are the same thing. Synthetics are just made by man not nature so they don't contain the flaws that lead to breakdown of viscosity and thermal sludging found in conventional oils. The only truth is that you wont benefit from using synthetics while not using them. They can even be mixed together no problem. If you don't believe this then what do you think synthetic conventional blends are? Use common sense people.
Anonymous Profile
Anonymous answered
I drive 1000 miles a week and have switched back and forth many times with out any problems. I change my oil every 3000 miles. My currant car has 210,000 miles on it. I have done this for 20 years. I have often used Walmart oil. Most of the oil web sites ( Castrol, Valvoline ) say you can switch back and forth with no problems.
Anonymous Profile
Anonymous answered
I had just changed the oil my girlfriends car and used Mobile 1 in it.  Forgetting that it is synthetic, I really did not want to keep putting Mobile 1 back in the car due to the price of it.  So when I returned to work the next day I asked my fellow mechanics, who have been working on vehicles for a combine of 25 years, if it was safe to return to conventional oil.  They said it would not damage the engine at all.  They said that both have the same structure base.  After that day I checked to see what kind of oil I have been putting in my own vehicle.  When I take it to the garage to get the oil change they use Mobile conventional in it.  But because I have a small oil leak in my 1995 Prelude, which has 241,000 miles on it, I have to keep adding a little oil every week between oil changes I have been putting Mobile 1 in it.  I have been doing this for probably a year now.  It has not affected my motor and it still runs great with the amount of miles it has.  So after all this I guess I could have answered my own question.  "Can you switch back to conventional after using synthetic?"  Yes You Can!
Anonymous Profile
Anonymous answered
No it doesn't matter.   The oils are compatible.   Synthetic oil is derived from crude just like Conventional but they put it through a process to make all the molecules the same size so that they can form a better "film" in the engine.   Plus the molecules have a tendency to not become completely destroyed like Conventional oils do thus providing longer oil life.   The myth is that if your car has run Conventional it's whole life and you switch to Synthetic that it will destroy the seals and cause leaks but this is false and unfortunately for the person trying to extend the life of their engine it is often perpetuated by auto shop sales people (or this has been my experience).   The oil is the life blood of your motor and Synthetic is by far superior to Conventional so if the price is not of much concern to you I would highly recommend Synthetic for keeping your motor lubricated.
Anonymous Profile
Anonymous answered
It makes no difference to switch back and forth. It will do no damage to your car. But synthetic is a better product. Thats all there is to it. If money is the bottom line use conventional. If your car is all that matters, use synthetic. Anyone who knows what they are talking about will tell you you arent going to hurt your car if you switch back. They will also tell you that synthetic is better, and you pay more for it.

~unbiased and informed
Anonymous Profile
Anonymous answered
Too many myths being perpetuated by peoples opinions and not fact here. The truth is that synthetic and conventional oils are completely compatible with one another. Switching to/from either will cause no damage or harm to your car's engine.

A simple search on any of the oil manufacturer websites will verify. Anyone telling you differently is simply uninformed and/or ignorant.
Anonymous Profile
Anonymous answered
Yes 40 years of turning wrenches. Only one difference in both oils and I also worked in a petroleum lab and know the difference. Yes no problems just don't drive the same difference make sure to change regular oil every 3months or 3000 miles which ever come first. Synthetic do not go by what the bottle says 5000 to 7500 or 6 months which ever come first.
Pat Merrifield Profile
Pat Merrifield answered
I agree with Jannifer that the synthetic is by far the best oil to run in your vehicle. Just the extended oil change intervals make it pay for itself, not leaving out the better protection for your vehicle's engine. I run sythetic in 4 of my 5 vehicles. All that being said I see no reason why you can't return to regular oil with no problem. I have done so many times and have seen no ill effects.
Anonymous Profile
Anonymous answered
I think you should not because in most of the cases there are a number of problems of oil leaking and other which can cause harm to your vehicle. Keep using Synthetic oil and this would be better. For more details click on the link:Oil use

titch Profile
titch answered
In my opinion high performence engines are designed to use  fully synthetic lubricants simply because of its higher tollerance and extended life...then you have semi synthetic for lower end engines...so it really depends what engine your putting it in...you can mix oils only as long as its of the same viscosity(thickness)
Anonymous Profile
Anonymous answered
Probably not a good idea. Synthetics are 'smoother,' for lack of a better term, and don't create as much sludge which robs your engine of not only power but mileage. Stick to the syns would be my advice.
B.R.K KING Profile
B.R.K KING answered
With 45yrs of turning a wrench and also drag racing super comp an top alcohol DO NOT SWITCH BACK OK!! Why oil conventional or synthetic use different compounds (cleaning agents and molecular binders) and an endless list of agents 4 heat dissipation. Oil does two basic things lubricates between moving parts and dissipates heat. I personally use Castrol Syntec there is more spendy oil and very good oil (Lucas, royal purple) in the top alcohol car we use Lucas they (help pay the bills)
anonymos Private Profile

Everyone who commented on this page is correct.  The reason the answers are polar opposites is very simple.  When synthetics FIRST CAME OUT there were issues in how they reacted with engine seals and even with NOT switching back seals would leak.  Then switching back made things much worse.  

That is no longer the case and has not been for quite some times.  You can now switch back and forth at will.  A simple search will reveal everything I said to be true.

Anonymous Profile
Anonymous answered
I asked this same question to my company mechanic a few weeks ago. He said if I switch from oil to a synthetic I would have use it for then on with no going back to conventional oil.
Anonymous Profile
Anonymous answered
NO!!!! After using synthetic you can never go back to using conventional unless you want to get a new car! I am glad I could help! And I hope (if you do get a new car) it's a nice one!

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