My recommendation to flush the engine before going to full synthetic is based off of instructions on the manufacturerâ€™s web sites and/or speaking with their technical advisors (Amsoil, Valvoline and Mobile one). I haven't done this yet myself but I had planned to go to full synthetic in the next few months so Iâ€™ve been looking around and calling their customer service depts and speaking with their technicians to get answers to my questions.Originally posted by mikehawk@Jun 24 2004, 10:09 PM
You NEVER have to flush an engine before switching to synthetic. Synthetic oils clean better than conventional oils anyway, so within a few (synthetic) oil changes you will have cleaned out a good amount of the sludge, anyway.
I've heard that those motor flushes are actually bad for your engine because they wash ALL the lubrication off all the moving parts causing a dry start that sometimes causes your motor to seize.
Eh, who knows. They could have just been trying to sell me another one of their products (the flush), which wouldn't surprise me. Like i said this is just what i was told by the companies technical advisors. It sucks when you can't even believe the makers of the productOriginally posted by madness_spirit@Jun 25 2004, 12:14 AM
I have never heard anything about you needing to flush an engine to switch to synthetic, and I was in a united auto workers school only 3 years ago. There is absolutely no reason why you would have to flush to switch to a synthetic, synthetics will mix well with conventional oils, and in the small amounts that you will have in an engine after an oil change you would never have to worry. A flush is nice though if you want to get everything super clean.
If an older engine is in good condition and does not have any leaks using Mobil 1 or other synthetics will have the same benefits as on an older engine. The condition of the engine and prior maintenance has more impact than just mileage when considering using synthetics. There are synthetic blends available for higher mileage engines now that contain more cleaning additives then regular blends. It really depends on the individual vehicle, especially nowadays when modern electronic engines are in much better shape after many miles then older vehicles were.Originally posted by snakeeyes@Jun 26 2004, 06:11 PM
The trick with synthetic is you gotta start using it when the engine has low miles. Otherwise the engine will never adapt to it. I changed to it today, Mobil 1 0-20. I have 45,000 on my car. That mileage might be pushing it,but I think it will still be O.K. I would say 75,000 or more and your wasting your time changing to Synthetic.