Are there many of you out there that use 10w30 motor oil in the 3.8 engine.

I'd imagine so since that'* the recommendation printed on the fill cover.

My filler cap say'* 5w30 so how stuiped could you be.

Maybe you should check the attitude, and use whats on your cap, and we'll use what'* on ours.

It would also help if you put your year and trim level in your signature so we know what you have.

Your owners manual has the oil requirements for the various climates and times of the year you will encounter.

As to the intent of your question, there probably are people who run different weight oil than is recommended. Their reasons will vary, but I see it all the time.

In general, it is NOT a good idea to run an oil weight different than what is recommended by the manufacturer. There are many reasons for this, not the least of which are the design tolerances and the sizes of the various oil passages in your engine.

With only a few exceptions, most reasons that people run higher weight oils would be better served by a proper repair and not just an oil "cover up".

You could use both in your engine, i believe your manual states both,
also a 5w30 will protect as good as 10w30(long story short)

i use 5w30 in everything i own

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Multi-weight oils (such as 10W-30) are a new invention made possible by adding polymers to oil. The polymers allow the oil to have different weights at different temperatures. The first number indicates the viscosity of the oil at a cold temperature, while the second number indicates the viscosity at operating temperature. This page from the Sci.Electronics.Repair FAQ offers the following very interesting description of how the polymers work:

At cold temperatures, the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up, the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C, the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot.

So it doesnt matter if you use 5w30 or 10w30 it is the same at opp temps
Thats y I use 5w30 all year

I have never heard that before. I was taught in 10W-30, 10 is the density and 30 is the viscosity, on whatever scales. Nothing about multiple viscosities. Was I not given all the info by my chemistry teacher?