It appears that this thread has turned into an a$$hole contest, and it looks like wileycwr has won it hands down.

 

Ever been to Florida?

 

The narrower the oil viscosity the better because viscosity improvers (VI) can and do break down over time. Oil can and does shear/ thicken over time. This is usually a factor when running longer oil change intervals. With 3,000 mile oil changes it's unlikely to be a factor. Drive on.

 

Somewhat true for conventional oil but not for synthetic.

 

As previously stated, FSM calls for a minimum of 13psi at hot idle. That's low. I've never seen my 4.0 read that low. Usually for the first 20 minutes or so of driving it's right up around 40 at idle, then when the oil thins out it drops to around 20. For some reason my buddies think that low oil pressure means my oil level is low.. "Dude holy crap, do you ever check your oil?!"

 

Somewhat true. GM still voids warranty for wide spread oils i.e. 10 w 50 b/c of ring sticking issues. This issue has now been mostly resolved though better chemistry. This used to be the reason for NOT using multigrade in air cooled engines.....NOW, it is recommended for most small air cooled engines.

 

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It is true for both.

 

FSM does not state that you NEED 13 psi. It implies that your engine wear tolerances are inadequate if below 13 psi.

 

Good point. It doesn't need 13psi, it wants it.

 

Not that I have one but what is the oil pressure when the warning light comes on?

 

Read Motor Oil 103.

 

Read Motor Oil 105.

 

Not really. Many synthetics meet API's requirements for so-called "multigrade" without using any VIIs. Regardless, this isn't the '60s anymore. In most scenarios, VIIs shearing down to the point of a problem is not a concern. Very long OCIs or racing applications are examples of exceptions.

10-13 PSI lol. It's not that accurate in the first place.

Not really. All it says is fix the engine if it's that low.

 

for the dummy gage it is 4psi. I have bench tested 3 sensors and they were the same.

 

Synthetics still contain VI and will shear/ thicken out of grade. Like I said, with low oil change intervals its unlikely to be a problem. I would like to see your list of synthetics that do not contain VI.