Originally Posted by PaulZ370

Heat Soak while you are traveling at high speed? I can understand if you are sitting or traveling at very low speeds in traffic, but then, the effect is negligible as you are not trying to go WOT in traffic... Once you reach open highway, it may take a couple of minutes of high-er speeds to get rid of the trapped hot air under the hood.

Oil temps climb rapidly due to the way the oil sump pump and oil delivery system in the Z is designed. Very little oil stays in the sump during WOT (or spirited driving) and almost all of it is used in circulating through the engine for protection of the moving parts. I suggest you might want to upgrade your sump to a larger capacity pan to keep your oil temps cooler if that is what you are experiencing. Have you thought of doing that?

afterthought: Also, I've never seen my water temps fluctuate that much, if at all... you may want to consider checking your cooling system. Might be a leak somewhere. In a pressurized cooling system, temps should remain stable, but if you even have a pin hole leak somewhere, water will transition to steam (which is not good for heat absorption and conduction) and your temps will start 'skyrocketing' as you say.... I would definitely give your Z a good look under the hood. Something does not add up straight, and it's not the Typhoons...