oil question! please give opinion
 

Hello all,

I have gotten to many diff opinion on oil I dont even know where to turn
1. one gentlemen told me to always always follow the manual, my manual says 5w20

2. my mechanic when i told him I was running 5w20 laughed in my face and told me I better switch on my next oil change to 5w30 for the winter and 10w30 for the summer

I dont know what to do so I am turning to a forum to help me out.

Car details:

2002 Mercury Sable LS Premium
Duratec DOHC v6
118,000

I live in Queens, NY

I drive everyday and do road trips (about 300 miles round trip) once a month

Thank You!

I've found over the years (don't ask how many) it is nearly always the best policy to follow the owner's manual.
I don't think the difference between those grades you listed are that important. Your mechanic is thinking that on a real hot day with the air conditioner running and you are stuck in traffic or something,it might be nice to have a thicker oil in there than 5/20. I tend to agree with him on this point. If your cooling system is good and you don't see the coolant temp.gauge going past the middle of the range then I think 5/20 is good for the cooler months. Personally I will switch to 5/30 for summer.

The reason for the 5/20 recommendation is that engine tolerance is a lot tighter than they use to be, & oil quality is a lot better. Before it was not unusual to use a quart of oil in just a few 1,000's miles. Another reason they have done so is for better fuel economy to meet the cafe standards.

The 5/30 also has a different additive package to get the increase weight range. Your best bet is to stay with the manufacturers recommendation. On the other hand if you live where the normal summer temperature is 100+ like in Arizona, the 5/30 might be a better bet. Would the 10/30 hurt anything in cooler temperatures. I don't think so other than a very slight loss in fuel economy.

Bulldozer,those are my thoughts exactly.

In my case,I drive across the Mojave desert in the summer where the ambient temps reach 130 near the pavement and there are some long grades as well (Baker grade for one,12 miles long),and I just feel better with a 30 wt. (I put 20/50 in my old (86 Toyota Cressida and it ran fine).

Oil Question
 

In your case you have no use for winter grades. As a retired truck driver, I'm familiar with that grade climbing out of Baker & know summer temperatures is above that century mark. In your case I would use the 10w-30 also, & maybe even go with synthetic if you don't have an oil consumption problem.

Thanks BD,that's exactly the plan. This Grand M has 25K miles and doesn't seem to use any oil to speak of. I use Mobile 1 in my '69 GMC and I believe I'll use it on this car too.

25,000 miles. Was it parked most of it's life? My 09 Grand M has 32,000 miles.

Elderly couple only used it to go to store,doctor etc. The old guy changed the oil every 5-6 months though, even if it had only been 1,000 miles. I feel like I'm getting a brand new car for $5,000. I've even got the window sticker and all the original paper work.
Same with my GMC 2500 PU,original owner nearly perfect original cond (this is Calif=no rust); $350.
I am thinking that the Merc is well broken in now and maybe time to go synthetic.