I believe a 30 weight is recommended for most 'G's. Higher viscosity oil can result in higher temperature both due to the parasitic load of the oil itself and possibly lower heat removal due to flow.

 

5w30 amsoil

 

you obviously haven't tried it. The results are actually the opposite of what you posted.

 

Note that what I am speaking of is the effect of high viscosity on temperature not temperature on viscosity.

A higher viscosity oil can result in lower flow rates. Heat transfer is greatly influenced by temperature differential. Higher viscosity oil requires more effort to pump through the numerous passages of an engine. This load increase will cause heat that then needs to be removed. Too high of viscosity oil can result in a condition called 'oil wedge'. You can think of this as the oil forming a wedge on one side of a shaft with a babbet bearing forcing the shaft towards the other side which is running dry. The oil is simply too thick to get out of its own way based on the clearance.

I retired after 35 years of operating water turbines, gas turbines, and steam turbines of up to 1 million hp and accessories including open and closed cycle cooling systems.

A quote from one site:

'If the lubricant is too viscous, it either does not flow into the bearing surface, causing lube starvation, and thus certain bearing damage. Or it consumes too much energy, which is then converted to heat and the bearing may be overheated, at which point it can seize due to loss of running clearance.'

Another quote, this one from:

http://machinedesign.com/article/her...ings-cool-0421

'Oil viscosity

The simplest way to lower bearing temperature is using lower-viscosity oil. The Viscosity and Oil Performance table illustrates typical effects when ISO viscosity grades for industrial mineral oils drop from VG 100 to VG 68, 46, and 32.'

Now in the case of the poster one also has to remember that the recommended viscosity also has to do with use. On various engines you may get a slight lubrication improvement on the bottom end of the engine due to oil film thickness with a little higher viscosity oil than recommended. In those situations you usually will pay however on the upper end of the engine due to flow characteristics. Some of this also has to do with type of bearings used, babbet versus roller, clearances encountered, and the rpm associated with the area being lubricated between parts.

 

First off if you have not yet sealed the deal on the OC motor your driving habits would be better discussed elsewhere.

If you are getting a new engine you many want to consider an add on oil system to included a partial bypass system. If going this route on a passenger car, especially if driven by someone else I would also consider a idiot light or alarm when doing so. Basically with a normal system you are filtering all of your oil in a single pass until the filter is plugged and then it goes into bypass mode. The oil filter is therefore limited in filtration capabilities for various reasons one of which is that when cold you could end up with lost of flow.

In a partial bypass system only some of the oil is filtered and then returned to the sump. This allows a much finer filter media to be used. The hazard is that a minor failure can easily lead to a major one due to particles flowing to the engine. Such systems often have chip detectors which indicated particles in your oil. Truckers and some labs have reported good oil to exist at up to 1,000,000 miles with nothing but filter changes, with many at the 250k mark. I would not recommend going that long but I would really consider such a system if interested in getting the most out of your engine.

Of course the same situation exist in most normal oil filters when they plug up and go into bypass mode. An easy fix here is to use an external non-bypass filter with a bypass valve that has a pressure switch. When in bypass mode you will get a light, buzzer, whatever to tell you so. Even dirty oil is often better than none for a short time.

 

amsoil syn 0w30

 

Probably a good choice. While I have always used other brands and have had many cars around the 200k point and one above 300 k my Dad always used Amsoil since it came out and he had similar results. Of course I followed his lead in making sure you changed the filter frequently even if not changing the oil. You started the car and while not letting it idle for long before driving you were careful to keep the rpms down until at operating temps to avoid spinning a bearing. In cold weather you turned the lights on as soon as the car started to place a load on the engine. You drove smoothly not to be confused with slowly. Treat your car well and it will return the favor.

 

I have been using Mobile 1 0W/40 since I purchased my car in 2003. It has been recommended highly for the Florida temps.

 

i live in fl and i use 20w50

 

Castrol Syntec 5W/30 here works great, and UOA's show great wear.

 

Synths in general handle high heat from engine better than dinos in the long run. If really concerned of high oil temps, do a oil cooler and/or extra capacity pan.

Amsoil ASL 5w-30 here.

 

+1. If anything, go slightly heavier weight, but 5w30 is fine. I roadrace motorcycles and we use heavier weight (20-50) over OEM specs, purely for protection.