oil light on at high speed and very hot outside

[Pat Conlon]

You do not want air bubbles in your oil.

[racerrad8]

it's good to know that 4 qts is still below the froth level (where the crank throws are below the  oil level and turn the oil to foam).

Just for clarification, it is not the crankshaft that causes oil aeration in the FJ, it is the clutch basket & clutch assembly.

One other thing to consider regarding oil level is the use of larger coolers & oil filters and the fact 4 qts might not be enough. It is very important to follow the factory oil level checking & setting procedures. If you have a larger oil filter or oil cooler and either one of them drains back overnight the oil level will show full or over full. Once you run the engine and refill  the oil filter or cooler and allow the oil to warm up to proper expansion then the oil level should be checked and adjusted.

On another note, I now have new replacement Yamaha Oil Level Sensors in stock to replace those 25+ year floats that are not "floating" as well as they used to.

Randy - RPM