Would it be ok to start using synthetic oil in my hemi? It is an 03 with 78 thousand miles. I have heard that if you switch once you have higher miles it may burn a little oil because the engine could be worn down from using conventional. I know the oil was changed very diligently because I acquired the truck from a family member. I am due for a change so I was thinking of switching for a little better gas mileage. Thanks

 

I've been using Royal Purple since I bought my '07. Runs great no issues. It had 10,000 on it when I bought it and the previous owner was using dino oil. I don't know if you'll get more mileage, but full synthetic is a better oil than dino IMHO

 

Agreed, I had a bit of a tick until I switched to Royal Purple and a K&N Filter

 

The synthetic won't improve the mileage enough to even pay the extra oil cost. Your oil change interval won't change (the oil gets dirty at the same rate). I use dino oil on all but my Mazda. It get synthetic because of the turbo. Nothing wrong with synthetic, it just isn't the be-all, end-all folks think it is.

 

Ok. Will it be safe to switch though because I have 78k?

 

Should be. I'm at 64,500.

 

It is safe to switch at any milage, and you can switch back at any time. Many people will say that you cant switch back and forth but thats BS! I switched to full synthetic and I noticed a difference in my mpg's, not a huge increase but a noticable one. I also noticed more power, and my truck running smoother in idle. Your oil change interval will change, and you can go an easy 5,000-6,000 between changes. I have 4,000 on my full synthetic oil and it still looks new. Conventional oils get discolored and wear out faster because they are affected by heat unlike synthetic oil which doesnt break down from heat. In my opinion it is deffinitely worth the extra money, and if you try it and dont think so you can go back to conventional without a problem.

 

I run Mobil 1 5W20 in my 07 5.7L, It will not affect anything, synthetic oil is made more for temp. extremes, on start up there is some metal on metal contact while the oil is pumped to the top of the engine. Synthetic oil is man made and has much smaller particles so it can be pumped to the top of the engine faster on start up to reduce wear. You do not need to use it. You can switch back and forth as much as you want. But just remember, Your oil may be able to go 8000 mi between oil changes, but that oil filter wont last more that 3000mi.

I'm Canadian so i got 4000km for every oil change. But im also the assistant manager at Mr.Lube here so I get it dirt cheap.

 

Switch around as needed. You can even mix 'em (FWIW).

 

Alright thanks guys. I was at walmart earlier looking at the oils and how is it that 5qts of Valvoline full synthetic is $16 and some others like castrol and penzoil are $30? Is there really a difference? I see alot of people on here running mobil1 so I was looking at that and I saw they have a fuel economy oil which instead of 5w-30 it was 0w-30. Would that really make a difference and would it be safe