From reading up on Synthetic vs. Conventional Motor Oil, All i see are Pro's compared to Con's, Mainly because i will be looking to use it in a 1999 Honda Civic Si, and not a new car (Because reportibly, Synthetic reduces the friction within the engine that is needed to 'break in' a new engine).

Is it safe/smart to switch to synthetic oil on an older car that has been using Conventional Motor Oil up until the point of the switch?
Any imput is greatly appreciated Thank you.

Edit: Also, is Mobil 1 the best synthetic out there? I read somewhere on here to stay away from Castrol Syntec. Yes? No?

 

I have the exact same car as you and ive been using syntethic oil, i love it.

 

And did you just purchase the car used, drain it, pop in the synthetic and replace the oil filter? I'm in limbo with this decision. Also, Mobil 1? Thank you for the response!

 

I bought my car about a year ago, and yeah i just drained the oil out and switched it with syntethic oil and replaced the filter. Syntethic oil lasts longer, but you have to change the filter every 3000 miles or just get a high mileage filter.

 

I switched mine to Mobil 1. Switching is no problem. Just drain and replace. Some say it will make your seals leak, truth is any older car is prone to seal leakage no matter what oil.

I'm not sure I agree with extending the change time. Keep changing oil every 5000 miles or sooner.

 

Oh and i used to use valvoleen, but i just switched to royal purple and i swear i have at least two more horsepower from it.

 

The rumor i've heard is that synthetic oil swells the oil seals, is that true, or in fact, a rumor? I think it is more beneficial to switch, and change around 5k (Give or take), With the filter around 2,500 miles.

 

Psh. Are you making an educated guess? Where are your facts? Have you done tests?It's more beneficial...hah. The oil companies make money every time you change your oil. When you use synthetic oil, don't bother changing it before it says to. You might think you're "babying" your car, but all you're doing is wasting your money and perfectly good oil for no reason. And the rumor is false.

 

More beneficial for the Engine itself, Since it will have less resistance (Friction) and therefor run cooler. I was simply asking about the Oil seals because i have never used Synthetic Oil myself. Just exploring every aspect. No need to be hostile. Thank you to everyone that posted.

 

The only thing that people say is that since the seals are old, synthetic oil is a lot thinner, so they sometimes leak.