I have a 2005 Chevy Silverado HD2500 duramax diesel with 115,000 miles. The engine is in good condition and uses no oil. I’m wondering if it would be good for the engine if I switched to Synthetic oil as opposed to the regular oil for diesel engines.
The regular stuff got you THIS far, keep doing what you are doing!
That said, I am a die-hard synthetic oil user in everything I own. IF you want to switch now at 115K miles, make the change using synthetic DIESEL spec oil like Rotella T6 or similar and plan a very short oil change interval (like 2000 miles or less) AND check the oil level at every week until the change. The oil will likely come out VERY dirty and you may use a quart every 500 miles. The oil is cleaning out the muck inside the engine. The oil usage will get back to normal in an oil change or 2 so keep an eye on it.