Is Synthetic worth it?

[rcmaniac791]

I can attest to the leaking with synthetic. I have a pair of older Deere lawn tractors with Kohler engines on them. I thought it would be cool to run synthetic in them. They started to burn more oil and one of them started to leak pretty badly. Went back to regular oil and the issues pretty much went away. I know these are small engines, but still.

The only gaskets that I have replaced in the 5th are the valve cover gaskets. Twice. And since the mating surface where the gasket sits on the head is not machined but only cast, they still seep ever so slightly. Everything else is factory as of now. The engine doesn't leak much, just the occasional drip once and awhile, but I don't have to add oil between changes.

 

[kkritsilas]

A little bit of an add on to the oil discussion, specifically with the reduction of ZDDP. See the following link:

https://www.rockauto.com/Newsletter/

Around 2/3 of the way down the page, there is a section called “Modern Engines and oil Consumption”. It has mostly to do with how reducing internal friction in modern engines has allowed oil consumption to increase (most likely due to reduced piston ring tension). It also specifically says that ZDDP, while necessary in engines with flat tappets/lifters, was reduced in 2010 specifically to allow more oil to get to the catalytic converter, without having the ZDDP “poison” the catalytic converter. I knew that the ZDDP had been reduced in newer engine oils, but never knew the reason or the specific date.