My wife's car has been running synthetic for it's whole life. She took it to a shop to get some work done & had them change the oil at that time. She neglected to tell them to put synthetic in it when they did it so now it's got regular SAE 10w-something in it. She hasn't driven it since we got it back from the shop so I'm wondering if I should just change it back to synthetic now, or does it matter? Thanks, -r
I can't really think of any reason why it should be a problem. If your concerned about it check with a local engine builder. Otherwise, run it and change back at the next oil change.
You should have no problems. Synthetics have to be compatable with petrobased oils just for the reasons mentioned. You probably need to change the non synthetic oil sooner than you are use to. Jim H
Don't sweat it. Run it 3k and switch back. I know its debateable and I might get flamed, but i.m.o. you are wasting your $ if you change synthetic at regular intervals on a daily driver. Let it go 7500-10k miles.
all oils can go longer then 3000 mile. that number came albout when we were driving on dirt roads ang had poor filters every thing is cleaner now. people that change oil every 3000 are waisting money and oil supply
Everything I've read (from both outside and inside the oil industry) says you can switch back with no problems. I'm kinda old school and it took me a long time to come around to using synthetic but now I use it all the time in my daily driver (2003 S-10 p/u) and change it @ 6,000-7,000 miles. Seems to work fine but I don't use it in any "old" engines. That 3,000 mile thing is a marketing ploy to sell more oil and oil changes. I could probably go to 8-10 thousand mile intervals but I just don't feel comfortable with that....Don.
I love synthetic ,but most of my toys won't hold it very well. I don't know if it's my assembly talent or what but it really leaks when I put it in a old ride. The only time I use it is when I have an oil burner and want to sell it. OOPs Never mind.
Some guys say synthetic oil is too slippery for flat tappet engines and the lifters won't rotate .Sound like bullshit???
Hey Truckedup, Yep, That's bullshit. Regular synthetics don't have zinc in them. Zinc is needed for high load pressure areas like flat tappet cams with higer than stock over the nose spring pressures. Racing synthetics like Valvoline Racing or Joe Gibbs Racing oils have zinc added. Joe Gibbs Racing Oils is makin' an oil for street hot rods now. Check their website for more info on it. Their prducts are real good quaility. Smokey
Randy, It's up to you but, you will be OK without switchin' back right away. What kind of car is it? I like synthetic in our TransAm cause the under hood temp is so high.Same thing with newer Vettes.
Change it afrter 3k and put some amsoil in it. Every 25k or once a year. My dad has 300,000 miles on his 2000 Dakota runs all amsoil and has never had trouble with anything drivetrain related yet. Changes it every 25k.
There is no problem with changing back any time. The modern synthetics are fully compatible with the standard petroleum oils. I have been selling and using Amsoil for 27 years, and I run synthetic in everything I own. That includes excavator, Bobcat, boat, antique engines, hi perf Chev and Ford engines and never had a problem. Synthetics cut down on maintenance costs. One thing, when using the extended change intervals, use the air and oil filters designed for extended change intervals. Bob 55 Cameo 396 TH 400 with overdrive 65 Caliente conv 67 BB Caliente conv 67 Mercury 1 Ton 76 GMC 3/4 ton 454ci 84 Buick Turbo Regal and not enough time
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