Originally Posted by Tombstone RJ
The synthetics I use are so light that they do burn off after a while and I'm not sure why there is no indication of fouling or things like that. Car passes emissions just fine too. I just think it's such a light oil that after a while it just tends to basically evaporate due to heat and friction and exit out the exhaust. Either my car is screwed or something is happening to the oil. Every mechanic that has looked at it says it's a great car and there's nothing wrong with it. But, I keep a spare quart of oil in the trunk and check the oil every few weeks, especially after about 3k after the oil change (it gets changed every 5-6k miles). The oil just gradually disappears somewhere and I have to top it off. I don't have to add a lot of oil, but I do have to add some oil after a while.
When syn burns it wont leave a trace on your plugs well sometimes a slight ash but that is it. Note DEQ if your car burns a little oil throw some syn in it and they will never know as long as it is not horrible.