Semi synthetic vs regular which is better?

This! Somebody was talking about idling an engine for 20 minutes somewhere, and I'm going "why would you bother? 5 minutes of easy driving will get your engine oil temp up better than sitting in the truckstop wasting fuel."

 

Yes, Even in sub zero temps I do not long term idle. Not even when I owned a b model cat.
I let engine run a few min. Then ease out under light throttle, until up to operating temp. Also allows drive train to get lubricant circulating, before hammering it. This not only help with fuel dilution because cyl temps and pressures come up. It causes the rings to seal against cyl walls. Idling allows cyl washing which the fuel isn’t completely burned and by passes the rings and removes the crucial layer of oil from the walls. Big reason newer trucks have so many emissions issues. Plugs face of DPF
As temps are not hot enough, not enough flow of exhaust. I am lucky I suppose never had a truck on a hook and so far my DD15
With over 450k has never had a problem. With emissions. Contribute to no idle, good maintenance and changing Def filter yearly, and keeping air system maintained. New trucks not all bad. Some older drivers just don’t want to change old habits or don’t care. New engines are different for sure.
I don’t run synthetic or semi synthetic. Reason I change my oil too often to benefit from it.
Even my old 02 gmc envoy with inline 6 my wife drove to 411,000 miles and my son still driving. Never used anything but straight 5/30 VALVOLINE in it. Every 3k miles. Oil life monitor would let it go 12k miles as she did highway driving. Clean fluids everywhere prolong the life of components. Just sends on what you want in the end.

 

Example I have been sitting at a customer for about an hour and a half 43 deg outside
Truck next to me a W900 with a N14 can tell by how it sounds. Driver has both windows down idling and a puddle of oil out the draft tube. Talk about a waste of fuel. His truck but that is what kills a engine prematurely

 

Yeah,,what is better? You'll get a rift of answers here, from, best creation since tubeless tires,,others, I used Rotella T, my daddy used it, HIS daddy used it, consarnit, nothing wrong with good old OIL oil. I was and still am in the OLD oil. Not sure why really, I have heard synthetic is superior. I'd certainly use it in a transmission or rear axle setting, I heard a transmission with synthetic shifts "like buttah", a motor that used or leaked oil, it just was too expensive,,in the short run, anyway. I bought a Jeep with synthetic oil, not sure I'm going to keep it once it's time to change,,,whenever THAT is, some say 5,000 miles, others 20,000!! As much as I use the Jeep, theoretically, I'll never have to change it. I'm also wondering if there's a problem going from synthetic back to petro based? Anyone?

 

I started using semi-synthetic 20+ years ago for just this reason. It made a huge difference in the cold, especially with the pre-electronic engines.

 

My truck does not get shut down winter at all, summer when it is too hot. Last engine dropped a valve at over 1.5 mln mi cuz I was lazy to rebuild the head, opened for an inframe, cylinders still had manufactured polishing scuffing on them. Talk about idling.

Delvac 1300 is all I use. Hitting close to 1.3 mln. At the same time.. it may be just my luck)

 

I know all the cold starts aren't good for the engines.

 

Yes, there is a problem.

The synthetic is better for seals, but when you go back to petro based you lose that.
The seals tend to harden up and fail.

It was the same with a motorcycle I once had.
I was using synthetic and went back to regular oil, and the clutch friction plates hardened as a result.

Once you go synthetic in an engine... never go back.

 

I would kindly disagree. Unless syn is used of a recommended viscosity, cuz they all are thinner now days, it may damage the engine. Seals can be replaced, dead engine that ran on a thin oil in hot weather, well, may be too, I'd guess.