BigJim, good morning. Yeah, I'm a chemist. I've mentioned that before. The majority of my career has been in the chemical water treatment industry. My only experiences with oil is breaking oil/water emulsions.
I'm not sure what you're getting at in your post. What's your point? Above I already made the point that for a Jeep engine, the recommended multiweight regular oil is more than adequate to protect the engine if the manufacturer's engine oil drain frequency is followed. From your posts above, you apparently are within most vehicle recommended drain frequencies.
Okay, for fun, I'll bite. Certainly, there are some risks in having any quick oil change shop change any lube oil system, whether it be the engine, tranny, t-case, or differential. If you're like me, you have actually gone back into the pump room and read the drum labels. Apparently, there are dealers and quick change shops that try to fit all the different vehicle oil requirements with only a few oils.
Yeah, I use a local grease monkey shop during the winter months rather than endure the frigid weather in the front driveway. They stopped carrying my valvoline engine oil. I'm going to see what they'll charge if I bring in my own oil for them to pour into my Jeeps, in the next few days. The engine oil gods recommend that the same oil (same brand) should be used. Even when topping off the engine oil ... same brand, same grade. They strongly recommend not using oil additives, and to only upgrade to blended or synthetic engine oils. The oil gods also recommend a flushing treatment between brand changes and upgrades. But, flushings are another scam put on the vheicle owners at quick change and dealer shops. Just getting the normally untrained help at quick change shops to put some grease in the few zerks Jeeps now have, is annoying. Unfortunately, it seems as if the local 4x4 shops are too busy installing lifts or whatever to provide this preventative maintenance service. Too bad! I think they're missing some lucrative business.
There, that should be enough to get your juices flowing, you old fart! <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />