How much longer would you go on fully synthetic motor oil?

Newer car not under warranty a 2003 with almost high mileage.How much longer would you go on fully synthetic motor oil?
Sinse there are no foreign or American car companies who recommend 3,000 mile oil changes it largely would be a waste of time and money. Under the best of conditions modern GM products with engine oil life monitors can go 8,500 miles between oil changes. I've noticed under the identical normal driving the oil life monitor ';knows'; weather or not I'm using full synthetic oil as the mileage will stretch out as much as 33%. Synthetic oil does not by a long shot break down as fast as regular oil. Read the specifications sheets on Redline and Mobil1. Castol Edge says nothing!





Using extended mileage ';any brand'; I wouldn't go over 10,000 miles regardless what Amziol, Mobil1 or Castrol says. Very few people operate their vehicles under perfect driving conditions which is all highway long mileage trips in hot weather.





With no-lead fuel all motor oil stays cleaner anyway. If the engine clearances and measurements are out of spec it's another whole ball game. Synthetic oil cant fix a crappy motor. Synthetic oil has a stronger dose of detergents, EP (extreme pressure) properties, flows better at low temperature, doesn't oxidize as fast at high temperatures.How much longer would you go on fully synthetic motor oil?
always remember that the oil itself does not wear out, the additives like the anti foaming agents do. under normal driving conditions, this takes about 5,000 miles. HOWEVER, to qualify as a normal driving trip, you can not carry a load, stop drive in traffic and so on. go with the scedule in the owners manual for that car.
If I were you, I would pretend that regular oil does NOT exist. There are so many benefits of using a good synthetic. Your engine will get cleaner each time you drive it. No sludge will form. Sensors will stay cleaner longer. Better MPG's. Longer change intervals (one year). Engine seals protected from wear and leaks. Bearings last longer. Hydraulic lifters stay quieter. Oil pressure Relief valve stays working best. Best protection for expensive engine internals. USE ONLY oil that has YOUR car name written on the label. E.g. ';designed for use in HONDA.'; or ';Meets VW/Audi specification 502/505. FORGET bulk, quicky lube oils. Buy your OWN oil and filter. Read your manual to see which specifications your particular car must have. Oils today are vehicle specific.
I go 5000 miles using Mobil 1 syn. and have 200k miles and engine runs like new. I heard that Popular Mechanics did a test on New York cabs and found there was no difference in wear between changing oil at 3k or 5k. For a normally street driven vehicle, not towing or turbocharged I don't see any reason for 3k changes.
3000





synthetic makes no difference, it still breaksdown the same as conventional oil.





Anyone that says otherwise - is full of BS
the same as you would on dinosaur oil. change both of those oils once every 3 months or 30000 miles.
as long as u want...or dont want...