JFNash

I just changed the engine oil (have driven around 2.5K miles in 4 months).

Before I changed the oil, the temperature meter would take about 2 minutes to start moving up and roughly 7 - 8 minutes to reach the normal point.

After the oil change, it would take the car less than a minute to start warming up and exactly 6 minutes to reach the typical temperature.

Both cases are morning starts (after at least 8 hours sitting in the garage).

I used Mobile 1 0W40 oil and have no idea what kind of oil was used in the car before, as this is the first time I change the engine oil since I imported the car from TX, US.

Any clue on why the car would warm up faster than before after the oil change?

Note: It's an '08 RWD LS460.

Thanks!

Mike_TX

The oil that came in the car was 5W20, and you have replaced it with a heavier-weight oil. I can only assume the engine generates and retains heat more quickly because it is not getting the same degree of lubrication when it's cold.

In other words, the heavier oil is not circulating as quickly and friction is generating more heat until the engine warms up and the oil circulates better.

Given that you're in Riyahd, and you *sometimes* experience warm weather there , it's probably not a bad idea to have the heavier-weight oil.

I wouldn't worry about it.

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JFNash

Thanks Mike for the informative response.

Yes you're right the weather here is quite warm much time of the year (but obviously not in December).

The engine oil used here with LS460 is either 0W40 or 5W40. I can't tell what the difference is, but some people use the one I use and others use 5W40.

Thanks again.

Mike_TX

OOPS! I re-read your original post and I now see you said "0W40" ... I misread that as "10W40".

So I have to say I'm not sure why your car would warm up faster with 0W40 than with the "standard" 5W40, unless it's because the oil circulates better when cold and spreads the engine heat throughout the block better (?)

I know that contradicts my original theory, which is another way of saying I don't really know. But there shouldn't be enough difference between the two weights of oil to matter. In fact, I believe the owner's manual specifies either one, depending on average outside temperatures.

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