I went to my local parts store a while ago to pick up some oil. since it was winter time and the temperature was about 12 degrees the sales manager told me to switch from using 5w-30 to using 10w-30 because 5w-30 will thin out in the winter and will not be able to perform as well as 10w-30 so i switched to 10w-30 now that its summertim should i switch back to 5w-30 then switch again every winter???
is this bad for your car???
I use mobile1 synthetic oil. Also he said i might want to take in consideration to use 10w-30 all the time since my car just turned 75,000 miles is this true also when a car gets older you should switch to 10w-30??? even though the manufactures manual says to use 5w-30 very puzzeled about this

 

I think that sales manager is way off. You want a thinner oil in the winter to help at engine start-up, that's when you want 5 weight. You could go to 10 weight in the summer but I stay at 5 weight all year round. FYI, I'm at 79,500 miles.

Don't listen to those guys.

 

Thats exactly what I was thinking.

 

Correct above!
If you run in very hot environments, then thicker oil. (10-30ish)
If you run in cold environments, then thin oil. (5-30ish)
Also may vary with age of motor...

When the oil is hot, it will thin out... thus already thin oil will be too thin...

dave h.

 

so what would you guys recomed i run in my maxima if i will be living in miami soon should i just switch to 10w30 all together or should i go with the manufactures recomendations for 5w30 i dont know if this makes a difference but keep in mind i do have 75,000 miles on my car

 

I run 10w 30 mobile one synthetic and have no problems, the reason I use a heavier oil is because one synthetic flows much better than conventional oil and when you run your car hard like i do all the time the oil has a tendancy to thin out. right now my car has 134,000 miles on it and uses about 3/4 to one quart of oil every 3000 miles, that may seem like alot but when you factor in that my rings (200psi comp) are great and there are no oil leaks, and the fact i dont hesitate to touch red line and love doing high speed runs down the interstate at 146 miles per hour( top speed so far--5600rpm) using a little oil shows that the valves are probably floating a bit. 5w30 would probably break down faster for me.

 

Stick with the 5w30 in the summer and winter. The oil can take it.

 

out of couristy can u put 0-40 oil or even perhapss 5-50?