cdnewton

Synthetic advantages = better cold driving characteristics, slightly increased fuel mileage, lower operating temperatures, better heat dissipation capability, and long term high temperature stability.

I am assuming a 5,000 oil change interval for synthetic and a 3,000 mile oil change for conventional with oil changes performed by the owner, not the dealership. Oil price is figured from Wal-Mart using an OEM Toyota/Lexus oil filter.

($20 for Pennzoil Platinum + $5 for oil filter) X (100,000 / 5,000) = $25 X 20 = $500

($10 for Pennzoil Conventional + $5 for oil filter) = (100,000 / 3,000) = $15 X 33 = $495

If you were to take both oils to a 5,000 mile interval, the difference would be $500 vs $300; so in about 100,000 miles, we are talking about a $200 difference for your $40,000 Lexus automobile.

Lextranny

I was chatting with one of the auto store employee and he told me to stay away from Pennzoil/Quaker both same company as they use a wax based oil.

He recommended either Valvoline, Castrol or Mobil 1.

I started using Castrol dino then slowly switched to Castrol Synthetic Blend (half dino, half synthetic) then now i'm using full Mobil 1 synthetic.

TunedRX300

Blends often have ~10% synthetic and Mobile 1 is not 100% synthetic. Do a search you will find Mobile 1 base stock is discussed multiple times already.

cdnewton

Synthetic base stocks are 100% paraffinic. Technically, paraffinic oil is a term used to describe the chemical structure, not the wax content. Through dewaxing in the refinery and the addition of pour point depressants during blending any harmful effects of wax are eliminated or neutralized.

Most people relate the word paraffin to candle wax. This is a correct association, BUT one of the most incorrect and widely circulated misconceptions about sludge is that it forms more easily in paraffin-based motor oils. This couldn't be further from the truth. All major motor oils, in fact, are formulated using a paraffin-based crude oil. Naphthenic-based crude oils are actually more likely to form sludge in an engine than oils formulated with paraffin-based crude oils. This is due to the higher breakdown resistance of paraffin-based crude oils.

Lextranny

I just noticed last night I have a leak. Is not dripping to the floor yet. But I see it on the bottom plastic cover. Not sure where exactly is coming from. I need to take the bottom part off to see it. But it is definetely oil. I just recently switched to Mobil 1 synthetic at 25k miles. Could it be the synthetic oil that messed up the gasket?

mandyfig

Dino to Syn should not mess up your seals. Does not make sense. Are you sure the leak's not been there?

Lexmex

Sometimes synthetic at the start of changeover from dino can leak the beginning.

biff44

One thing I usually do on the way to the oil change, is I will put a pint of Mavel Mystery oil in--just to clean up some of the sludge in the top end. Don't know if it really does much, but I have been doing it for years. Makes me feel good.

mandyfig

Should we start from blend perhaps? I am planning to do this on my next oil change, should I be worried?

Lexmex

I don't know that blends do it either. It is just the nature of synthetics, though I hear less and less the case about leaks than I did 5 or 10 years ago. In my family, what we do is go one weight higher say a 40, and then next oil change go back to a 30 after switching from dino.

mandyfig

So, like go to 5W-40 (?) 1st and back to 5W-30?

The G Man

Seal technology have come a long way since 10 years ago, there are less and less incidents of oil leak when switching from dino to synthetic. synthetic oil does not cause leaks, it just amplifies a seal problem that you already have. synthetic oil has smaller molecules than dino oil, therefore it can leak thru places that dino oil will not. If you have a well sealed engine to start with, switching to synthetic will not cause leaks.

cdnewton

If you are experiencing leaks after switching to synthetic, I would go with a High Mileage synthetic (like the new Mobil 1 10W30 HM), a dose of Auto-Rx (www.auto-rx.com) or back to conventional oil.

Lexmex

On high mileage vehicles this is a great idea. Auto-Rx is an excellent product and my uncle uses it on occasion here.

mandyfig

You are scaring me folks, I only have 26k on my RX330. Should I stick to dino then switch to syn when I hit 75K? I just bought a ton of 5-30 Pennzoil Platinums.