when is it too late to use synthetic oil

**jinouk67** · 06-30-2007, 05:19 AM

My gto has just passed 19000 miles mark, My last oil change was about 17000 miles mark i used synthetic blend.The car had 14000 miles when i purchased it & the previuos owner used regular oil. Will using full synthetic oil from now on ok ? Will it not make a difference since the cylinder walls have already got the wear from regular oil?

**Sarge** · 06-30-2007, 05:39 AM

You could have used synthetic from mile 1. There is no break in...that is a myth....

**jinouk67** · 06-30-2007, 05:56 AM

Is it a myth that synthetic oil will not help when you use on a engine that has somewhat excessive miles for example 15000-20000 miles ? Can you switch back from synthetic to regular oil down the road ?

**mtjoy** · 06-30-2007, 06:36 AM

If the previous owner changed the regular oil at the required intervals and used a good quality oil, there shouldn't be any excessive wear. I've torn down plenty of motors with 100,000+ miles running regular oil and the bearings didn't show any copper and there weren't ridges in the cylinders.

You can switch back and forth between regular and synthetic as you wish, in fact you can even mix them. You just don't want to mix viscosities.

**Sarge** · 07-01-2007, 03:17 PM

What mtjoy said so well....absolutely you can switch back and forth...and I totally agree with mtjoy that SM rated conventionals are on par with many synthetics when changed at 3K-5K oil change intervals...the line is blurred today between synthetics and conventionals....