Recently purchased a 2008 Aspen with a 5.7l, 230,000km / 143,000miles, suspect the previous owner ran synthetic oil in everything, not coonfirmed though, what are peoples thoughts on switching back to conventional Engine oil, I am thinking of doing this for the cost, is there eny way to tell if it's syn. or con.? Under the impression that switching back to con. from syn. is not a good idea.

 

Without maintenance records, you are not going to be able to know if previous owner used synthetic or conventional. Most dealers change the oil before selling on their lots so you probably have whatever stock oil they use in there now which will probably be conventional oil.

You can switch from synthetic to conventional. You just have to do changes more often as synthetic allows for extended use. The main thing is to use the correct weight (5w-20), check levels on a regular basis and complete changes on manufacturers recommended intervals (Manual says 6000 miles / 10000 KM or 6 months). I would not recommend exceeding the intervals with conventional oil.

 

Thank you

 

My 07 Aspen Limited 4x4 5.7L was using some oil on synthetic, so I switched to conventional 5w-20 and 1 blue bottle of STP and it runs great with MDS working fine and doesn't use oil any more, it has 158,000 on the clock; we love the car,still looks new, we bought it from original owner.