proog87

iTrader: (1)

I have a question for the oil experts out there. Is it ok to run 10w 30 on a Lexus IsF? I do understand that its just a bit thicker then 5w 30. To my opinion i think it would keep my engine cooler for the fact that it does not thin out as much as 5w but also worry that the tickness will cause a bit of restriction. But again its only my opinion of judgment. COULD SOME ONE PLEASE GIVE ME EXPERT SUGGESTIONS...

SCCAForums

You are fine either way... I live in AZ and still use the 5w30 Synthetic.

You risk more 'harm' in how long you leave it in, then which weight you choose, between those two.

Enjoy,
Dave

flowrider

iTrader: (9)

I live in Arizona also, and run 10-30 because of our summer heat and mild winters.

Lou

mikefate

I use 10w in summer and 5w in winter on all my cars

SCCAForums

FYI, the 5W or 10W is the 'Winter Flow' the 30 is the 'standard Flow at 210' So... I've always ran as light as I can, and still get the SAE 30 (or whatever the manufactures recommends)

Here is an excerpt from Amsoil on Oil Viscosity Rating:

OK . . .What does a 5W-30 do that an SAE 30 won't?
When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C). The difference is when the viscosity is tested at a much colder temperature. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear.

ISFer

iTrader: (2)

The '5' & '10' part of 5W30 and 10W30 concerns viscosity at cold starting.

I personally would use the 10W30 grade in your climate but I don't believe it would make much difference which is used.
The '5' would turn over a little easier and lubricate a little better than the '10', but after warmup there should be little difference.

C.

Koz

There is a little more to the "W" rating then just being better for cold or winter temps. Up to 80% of engine wear is from cold starts. This does not only pertain to cold weather. Cold start means the first start of the day after the engine has completely cooled/drained down. This wear accrues in the time the oil takes to get to the vital parts of the engine (bearings, cams, lifters, etc). The quicker the oil gets to those vital areas the less wear. That being said, the lower the weight the better/faster the oil will flow during start-up. The lower the number the better cold flow. 0w-30, 5w-30, 10w-30, all will provide approx the same protection against thermal breakdown, being that they all have the 30 weight rating. The difference is in the pour rate (ability to flow when cold). The lower the "w" (Winter) rating/viscosity the better flow at start up. The best viscosity to use is the lowest viscosity that falls within the OEM recommended range. 0w-30 will provide better wear protection then 10w-30 no matter what the temp!

Koz

lobuxracer

iTrader: (2)

Sure it's OK, but it won't do what you're suggesting. 10w-30 and 5w-30 are the same at normal operating temperature, so neither is thicker except when cold.

Thicker oils - 40, 50, 60 weight - use more horsepower to pump (hot or cold), create more fluid drag in service, and run hotter than 30 weight oils.

You would be wise to read this entire piece and get a solid education on how oil really works. Thankfully it's not marketing nor is the guy trying to sell oil, it's just solid information on a topic as controversial as religion.

jkeifer3

Yup, I agree and use 0w30 all the time.

Jetfire

iTrader: (3)

i read that link a few months ago and it was pure gold.

i prefer to run 0w-20 or 0w-30 because of better pour at cold startups.

proog87

iTrader: (1)

It seems that 0w 30 has won my debate. Thanks to everyone that participated in this post.

flowrider

iTrader: (9)

Concerning cold flow, my experience:

My wife has an ES, as you can see from my sig. Many ES owners have complained about valve clatter on startup with a cold engine. I've run 10W-30 Pennzoil Platinum in the ES since the first oil change at 4,985 miles. Her car did exhibit what I would consider mild valve clatter with the factory 5W-30. Since her first oil change, that noise has gone away. So, I can only surmise that in mild or hot climates, I am doing the right thing.

Lou