Minivan with almost 200,000 miles. 3.0 V6 Voyager. Not smoking which is pretty good, knock wood.
The dealer is using semi-synthetic Conoco 5W-30 oil. The dealer got it in bulk so it's being used instead of the much cheaper dinosaur oil.
I could be wrong, but the minivan seems to be using less oil with the semi-synthetic, which is very pleasing, if it's true. Hard to test because the dipstick on these cars is a hassle to use. So much so that I made some vinyl tubing and using it like a pipette to get an accurate reading. And even then it's up in the air. Others have noticed that this dipstick with bends and what not seems to pick up extra oil so it's not clear what the actual level is.
In any case, will the semi-synthetic possibly hurt such a mature engine? It's over 10 years of old and has been used to dinosaur oil.
Any recommendations? I have noticed High Mileage semi-synthetics and dinosaur oil. I got some Valvoline blended or semi-synthetic to top off. Also some dinosaur from Walmart's whic had a rating of SM in it's circle, which is pretty good.