What oil for summer?

[Guest]

What is the best oil to use during the summer? What would u recommend for my 113,000 mile eta? Thanks.

[lordofthewaters]

Well 10W40 is a good year round oil in my area, but I've used 20W50 in the summer months too. I'd recommend 10W40 for you, but that's just me.

Something like Mobil Clean High Mileage or Castrol GTX High Mileage

[DaveInLA]

I'm not sure what Michigan summers are like, but here in SoCal, I use Mobil 1 15w50. I used to use Castrol GTX 20w50 when I still filled with dino oil.

[lordofthewaters]

Ok according to my Bentley manual ( I just remembered there's a chart in there).

Viscosity requirement vs. temperature
5w20
-40F to 20F degrees

5w30
-40F to 25F

10w30
-20F to 40F

10w40
-20F to 50F

10w50
-20F to 70F

15w40
0F to 90F

15w50
0F to 105F

20w50
20F to 120F

SAE20
-20C to 10C Degrees

SAE 30
0C to 30C

SAE40
20C to 50C

[chuckybob]

anyone else find it a little odd that the oil temp range is rated for the external temperature, when the oil takes heat from the engine, and pretty much conforms to whatever temperature the thermostat is set to kick in at?

[arsevader]

anyone else find it a little odd that the oil temp range is rated for the external temperature, when the oil takes heat from the engine, and pretty much conforms to whatever temperature the thermostat is set to kick in at?

That's why the first number is really more important when taking outside temp into account. The first number should be appropriate to the temp you are operating in.

For example her in Canada I use 5W-50 in the winter to help with cold starts and I use 15W-50 the rest of the year. I use 15W-50 to top it off during the winter months due to the breakdown of the oil over time. The 50 is the same in both cases because I want the maximum viscosity at operating temperature.

[Sean]

I run 15w50 year round. :D