" Head bolt heater put in on left side, as sitting in seat. From what I read on here that is wrong. Any advice????? "
I'm not familiar with your model. However, according to TractorData, the L3540 has a 3 cylinder engine. The block heaters are typically installed on the left hand side of the 3 cylinder engines. It is only on the four cylinder engines that the heaters should go on the right hand side.
I doubt you have a lemon. However, I think it would be well worthwhile for you to go over your tractor carefully. Check all fluids, check loader and wheel bolts, and torque them to the manual's specs. On my brand-new L4240, I was surprised to find that the real wheels weren't properly torqued, the front axle was less than half filled with hydraulic fluid, and the main transmission was also short on hydraulic fluid (well below the "must fill" mark).
The dealer I bought the tractor from obtained it from another dealer. Apparently, neither dealer did a thorough job of going over the tractor. In a new car dealership, this would be totally unacceptable. Kubota dealers apparently don't hold themselves to as high a standard, which is disappointing.