ES3

Went to Jiffy Lube, their computer told them Lexus requires 10w 30? But on the oil cap on the engine it says 5w30? Which do you use, does it really matter?

steviej

iTrader: (1)

5w-30 if your car has under 75k miles on it.
Once over 75k start looking at 10w-30 with additives to help rejuvenate seals.

steviej

ES3

Cool, is 10w typically better or worse in summer weather?

Lexusfreak

I use what the owners manual calls for. I put Mobil 1 5W 30 synthetic with the Mobil 1 oil filter (Mobil part number M1-102). She dosen't burn a drop of oil.

steviej

iTrader: (1)

both will work equally well in the summer.

It is the cold temperature that separates the two:
10w30 is recommended for temps as low as 0°F and
5w30 is recommended for temps down to -20°F.

steviej

ES3

Got it, again, is the thought that 5w is better in colder becuase
it's less thick and more tolerable to gelling?

Lexusfreak

The 5W 30 flows much better in extreme cold temperatures mainly at start up. It gets to the vital engine parts sooner to avoid engine wear. Do you use Dino oil or synthetic?

ES3

I use the Dino stuff, have actually been going back and forth between 5 and 10w. At 117 thousand she doesn't leak a drop either, so something's working right. Regarding 10w, since it's thicker, that typically works better in the summer, when it's heated up, right?

steviej

iTrader: (1)

not exactly.
It doesn't matter whether it is winter or summer when the engine is at its normal operating temperature. The engine is far hotter than the ambient temperature outside the car. The normal operating temp of the engine is the same in winter and summer and will be the same for 5w and 10w. Both of them will perform about equally.

5w is better in extreme cold as Lexusfreak stated cause the engine is cold at start up and 5w is more free flowing than 10w in colder temps. This is only until the engine temp starts to warm up, then both oils will be quite liquid and free flowing.

In the summer, the outside temps may be 70-100°F depending on where you live and both 5w and 10w will be free flowing in a "cold" engine.

I hope this helps.

steviej

Lexusfreak

I understand there is even a 0W 30 synthetic oil out there too! I thonk thats overkill myself......unless you live in the top of the artic circle lol. It does claim to get excellent gas milage however, what do you think steviej?