this is just a survey that I'm doing. Which type of oil and weight do Z owners use and why? I've been asking this question to most people who Own Z cars from 260 to 300ZX and also some 240SX and Sylvia owners. So far Valvoline is on top. myself I use Valvoline Maxlife 20W-50. So far so good. it works good especially with our weather being 100++ during the summer and 75+ during the winter. so as you can tell we don't see snow. harldy any rain. So that is why most cars are rust free. Anyway thank you for participating.

"It can't rain all the time"

 

I use Valvoline 20w-50 or Castrol 20w-50 during the summer and 10w30 in the winter in my '77. I've had no problems at all with it other than slow cranking if I forget to change the oil when the weather gets super cold. When I rebuild my engine though, I plan to try Castrol Syntec. I use all sythetic gear oils though as they seem to run a little cooler and you can gain a few hp by reducing the friction.

Keep the greasy side down.
-Mo

 

When I started getting mine ready for the road, after sitting for 2 1/2 years, I replace the motor oil with 10W30 Castrol Syntec, the clutch and brake fluid with Valvoline Synthetic and when I replace the clutch I replace the transmission oil with Valvoline synthetic. Since I have a slight leak in the rear differential, I hope to replace that seal and refill with Valvoline Synthetic as well. If it helps I live in Arkansas which is 100+ Summers and sometimes -0 Winters.

 

I use Amsoil 10W-40 top synthetic (don't remember their marketing name for that line), year round. I'm in Boulder, CO, so over the winter it might be -20 F, and yesterday it was 102 F. No problems, and in fact remarkably good performance, low wear rates, etc. The multi-vis, along with the synthetic aspect, allows good viscosity in the heat and easy cranking in the cold. Downside? $6 per quart. But, I don't have any oil leaks and I only drive for fun, so it doesn't break the bank except for the initial up-front cost. I use Amsoil's 90 wt gear oil in the diff and transmission with similarly great results (again, don't remember their marketing name for the top-shelf stuff). That's all in '78 280Z's. I've heard of good results with Castrol's synthetics, Valvoline, and Redline as well. Only thing I've ever heard for "don'ts" is of course not to use synthetic in breaking in a new engine rebuild.

 

castrol 10w40 synthetics. Works good so far.