I own a 2000 Honda Accord LX that have 141,000 miles
Does anybody have any recommendation on oil viscosity?
Right now, it's getting close to summer & I was thinking I might buy Pennzoil 10w-30 High Mileage oil.
I'm not quite sure if I should use synthetic oil, wouldn't be a great transition.

Thanks

Oil questions are always a can of worms. Nobody will give you the same answer.

Me, if it's out of warranty, I use 10W30 year round. For the last several years I've been using Motorcraft semi-syn or Valvoline semi-syn, whichever is cheaper.

A Chevy with 145,000, Accord with 205,000, neither use oil, must be doing something right....

I think 10W-30 would be fine year-round in Georgia. Here, in Ohio, I usually follow the the owner's manual recommendation and use 5W-30 in Winter. This is with my Honda Accord that has 271K miles on it. I use regular oil, not synthetic, so i can't answer your question about synthetic.

are you burning oil between oil changes?!? if not, then just use regular oil like the others posted...

those hi-mileage oils have additives that sorta makes your seals swell a bit... to a lesser concentration than buying it off the shelf on a separate additive bottle...

something like this:

http://www.acehardwareoutlet.com/(lof3qaydbxyxlw232hcs2d3m)/ProductDetails.aspx?SKU=8106999