Semi synthetic vs regular which is better?

I prefer semi just because it lasts longer, is more forgiving if you need to kick a maintaince cycle down the road and seems to hold up better if your engine gets hot a lot say pulling hills. My oil samples say regular goes bad aftet 7k in my MX13 and semi usually lasts to about 20k or so. Also seems to crank better in the cold.

But everyone has a prefrence.

 

if you're not worried about budget, go for the longest lasting option and always change early. I always go for the closest to full synthetic and add Lucas additives in my regular vehicle. If you're changing before it goes bad then you're avoiding a lot of issues in the future. Clean oil means longer sensor life, better milage, less of a load on the internals, and less high cost maintenance. if you must use regular you should change very often. But overall full synthetic & change early. Why cheap out on a tool that keeps you making money

 

Also depends on the motor, i know in MY mx13 (your milage may vary literally here) full synthetic tends to get nasty a lot faster likely due to the poor maintaince before i got the rig and it trying to clean that stuff out. It also seems to burn the oil to the tune of a quart per 5k but with semi not a drop is burned and i can go my full 20k and use less then a pint.

This is why oil samples are important also why you gotta test with your rig. For me i am assumeing things are worn at 650k miles and the semi is more viscous and works better then the full and with said full also scrubbing things off it exposes more of that wear and tear on the engine.

 

At least you figured out how to make it burn less. Ill keep oil samples in mind but I believe when you got a few extra bucks you should figure out why you're burning so much. Most diesels are starting their life at 400k miles. I wouldn't be surprised if you have some internal damage. For some reason some people don't believe its important to change your oil on time. If you have a new or rebuilt turbo id bet your previous owner waited till it was thick sludge to change oil. Turbo is usually first to give before the motor goes downhill. If you haven't already id be changing that oil 2x in a row before it gets dirty just to clear things out. Run in 1k or so miles in between though. Good luck with your rig either way.

 

This is really a question?

For several decades synthetic has been better than organic in every way.

 

T6 and be done with it……

 

Hopefully guys that have put a million miles on their engines before doing an inframe chime in.

 

just my experience as a previous owner of the epa 10 EPA MX 13. Ran 3 in excess of 800k one to 1.1 million from new.
Nothing but Delvac 15/40 and 40k oil changes. Ran oil samples ever time. They usually only used less than 1/2 gallon of oil.
But I was meticulous with maintenance and
Overhead adjustments and emissions services.
They are a good engine. little miss understood by a lot of people.
Sure you’ll get yours cleaned out and it will give you great service.

 

Run Delvac 15/40 in everything
Had several engine I ran over million miles
Even my DD15’s run 15/40
My 2020 western star with 15/40
Gets 30k oil changes and great lab reports.
No oil usage yet at 450k
Don’t idle either. Haven’t idled a truck engine any longer than 5 min to warm up cool down in decades. Very hard on them