I had my truck oil changed at the new PTT on Chayangkun Rd. They have a pretty big operation at the back of the station where they do car washes and oil changes. I am 90% sure they are mixing new oil with some of your old and keeping the rest of the new. Normally when I get an oil change there is extra leftover and they give it to you in the jug. Other places usually put the extra oil in the back of the truck and I didn't check before heading home. When I got home I realized there was no extra oil and when I checked the oil, it was still quite black. A local friend of mine laughed and said that it's pretty common and to just find another place. I didn't bother going back to inquire. Anyone else had experience with this?

I'm always go to my Mitsu shop because of several reasons.

Once I had an oil change at a gas station, the whole bolt on which the oil filter is attached came off and I had to fix it. The guy then asked me if I was a mechanic.

I said no, that's only common sense.

And you don't pay more when you're going to a proper garage. Thais believe they pay less money, but have more problems at smaller places.

Just don't go to such places.=

Oh my! This story makes a lot of sense to me now that you opened my eyes to this scam. Next time I have an oil change done, I'm sticking around to watch. Thanks for the great info.