5W-30 in a Lesabre?

Does anyone use 5w-30 oil in a LeSabre or is 10W-30 as light as you can go?

I use 5w30 in my 1990 Lesabre. That is what the owner's manual reccomends.

Haynes Manual states: SAE 10W-30 (preferred for 3.4L DOHC, 3.8L Engines) O temperature and above. SAE 5W-30 (preferred for 3.1L and 3.4L OHV Engines) O temperture and below.
I use 5W-30 winter (about 3 mos. here) and 10W-30 summer.

Thanks for the information. I think the 5w30 has a much greater temp range. I've got '97 Lesabres (2)-forgot to mention the year. I think I'll put some 5W-30 in when I change the oil this time. I read on a web site that, the lighter the oil you use, the better your gas mileage will be. So, I thought I might test that out and see if it's true. The one that I drive all of the time has been getting about 23.5 mpg, combined city and highway, but mostly highway.

Drove an '05 Impala on a business trip this week. Kind of like those new Impalas. I cruised at about 78 mph. there and back, 274 miles. I checked the mileage upon returning. It got 29.453 miles to the gallon. Pretty good and the stero sounds great. I think it has a 3.4 ltr engine.