[He Rides A White Horse]

We have 4 vehicles with over 100K and one that probably has around 300K but the od hasn’t worked for many years. We put Slick 50 in everything when it gets past 50K.

I let the guys at Jiffy Lube take care of the oil, just not worth the time, and they put in the 'older vehicle' oil. I asked them what the difference was and was told that it was the equivalent of putting a quart of slick 50 in it.

You sound lucky.Owners manuals suggest 7,500 miles, and while the oils today are far superior, I change it around every 4,000 miles, to remove particles and dirt, that sort of thing. I guess that you are not putting too many miles on them (between changes).

[steve86]

Usually the high mileage oil has additives to keep the engine seals flexible or even swell them a little. Nothing to do with Teflon crap or whatever dubious ingredient Slick 50 has.

[Fresh Wind]

After some of the horror stories I’ve heard, I wouldn’t let my car get anywhere near a Jiffy Lube.