Im in central florida and was wondering what you thought about running straight weight oil compared to multi. I have been running straight 30 weight in my 72 ford truck and it seems to run fine. Just want some opinions.
Thanks, Jaret

 

The advantage of a multi weight is that you will have better flow characteristics at cold startup. Quicker oil pressure means a longer lasting engine. It's amazing how we can talk about the "good ol' days" concerning some of our vehicles but the truth is that the new vehicles and the "new" technologies are making our rigs last a lot longer. Life expectancy of a 72 was about 80-90,000 miles before an overhaul was necessary. Nowadays, the Tritons are designed around a 250,000 mile expectancy.

 

This worry about cold startup is simply not an issue in very warm climates. SAE 30 is even allowed in some GM engines during warranty operated above freezing. I ran my 4.3 V-6 on straight 30 during the summer because it cured leaks and high oil consumption on that engine. Straight 40 also cured smoking on an old Toyota. Multigrades are still rare in aircraft engines operated in temperate climates, SAE 50 is the most popular. Another place where single grade motor oil is specified, manual transmissions on some European cars.

Jim

 

i would run straight wt oil if i lived in fl

 

The "W" in multi-grade oils stands for winter, the oil's viscosity at 0F. It came about when polymers were introduced that allowed petroleum motors oils better flow characteristics in cold weather. Petroleum contains paraffins that are not refined out, and these wax, or gell at cold temperatures impeding flow. Without these pour point depressants, petroleum oil will cease to flow at around 5F above 0. That's probably why alot of engines wore out years ago before reaching 100,000 miles.

Living in a warm climate, I'd have no qualms about running a straight weight oil.

It's seems also, that the thinner oil weights are only run in North America for motor vehicles. Europeans always run 40 and 50wt. oils it seems, and their vehicles last, and in Germany, are driven at high speed on the Autobahn.