Is it a good idea to move from Synthetic oil to normal oil ?

[tmontague]

5w30 should be fine, but there is no way of really knowing if you exceed factory specs without knowing oil temp and/or pressure. None of which is available without an aftermarket gauge.

The only way going to a heavier weight oil makes sense is if you are operating above 212F oil temps, or if you want to reduce oil consumption and you notice it helps. You could try a 10w30 as they are slightly thicker than a 5w30 and potentially may reduce oil consumption. The difference between a 5w30 and a 10w30 isn't very big however as they both have to fall into the same viscosity spectrum at 100C. Most 10w30's are a big thicker at 150C due to a higher HTHS rating but like I said, it may not be noticeable enough for consumption issues.