Hoses for 99 windstar

I have a 2003 Jeep GC Laredo which has the OEM battery. I also have a boat with two deep-cycle Die Hards, date codes March 99 and June 2000. The boat has a single engine and I have a switch that allows me to use either or both batts. This switch is in the Off position when I'm not using the boat. The Jeep's battery is beginning to fail to hold a full charge but the two marine batts are still going strong. Prior to 1999/2000, the previous boat batts lasted ten years. Aside from the manufactured difference ("starting" versus "deep cycle"), the only thing I've done differently is store the boat batts in my attached garage for the winter with no trickle charge. The Jeep sits outside in the driveway, and winters get cold up here in Buffalo. Questions: -- Can I use a deep cycle for the Jeep? Stuff I've read says the only difference is the plate height is higher in a deep cycle so it takes longer for the gunk to build up on the bottom and short them. -- I've also read that the "cold cranking amps" spec is mostly marketing hype and that deep cycles can be used for starting. True? -- Are there advantages to trickle charging over the winter? -- When charging the boat batts, I've been switching to A or B. Is there a downside to leaving the switch set to both? Many thanks. -- RJ

I know there's no easy way to find the cause of a leak, but I have a 2002 Buick Century that has about 1,000 miles to go yet before it's oil change is due. Have had no warning signs other than yesterday my 'low oil' light came on. Had to put in 2 quarts. I now notice oil on the pavement. Could this be 'simple' or 'major" No oil on the engine as far as blowby. Any suggestions? Thank you!