Synthetic oil after 100k

**johnfin** · 06-19-2016, 05:35 PM

Is it ok to switch to synthetic after 100k miles. I have a new job where I drive to work an hour early way 70-100 mph so i am thinking of a better oil. And if I change over what should the change interval be?

**DarrenWS6** · 06-24-2016, 02:08 PM

Perfectly fine to switch at any time. I run Amsoil 5w30 in my daily driver 2.2L. I do 5,000 - 6,000 intervals along with a tank of fuel system treatment ( Amsoil fuel system cleaner ). It's been a good 54,000 miles in 3 years with this combo.

**pajeff02** · 06-24-2016, 05:40 PM

I run full synthetic and quality filters on our DD's with a 7,500 mile change interval.

**Inferno WS6** · 06-29-2016, 05:24 PM

Pennzoil platinum and fram ultra oil filter on my dd with 159k

**RUFFTURBO911** · 08-18-2016, 06:34 AM

I was skeptical because years ago I had a 1986 grand national and when I switched to Mobil 1 it started leaking oil like a sieve. If I was parked for a half hour I would have a 2 inch diameter spot under my car. For this reason I was a little bit hesitant, but my new (old) 58K LS1 had not been given an oil change in a little while due to the prior owner not driving her that much, so I dumped the Purolator filter and oil which didn't look bad for a mix of Castrol GTX and Castrol Magnetec 50/50 mix. I used the M1 oil filter and my pressure jumped 20 pounds at idle from roughly 20 to 40 PSI. No leaks so far but I probably only have about 10 to 15% of the oil synthetic. My friend says that everything is O-ringed on the engine and there shouldn't be any issues. In the next couple years I will slowly incorporate synth until I get to 100% synthetic but I'm still kind of concerned about a rear main seal leak. Good to see nobody's had a problem with an older vehicle switch to synthetic.

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