# sae 30



## elf

Just wondering how badly it would hurt an engine to put in SAE30 oil instead of regular 10w40(or 30 depending on what you use I reckon) does anyone know?


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## Guest

Hi elf,

I am not a mechanic but have worked around this stuff quite a bit during my life by being a former country boy who dealt a lot with machinery and engines.

Here is the skinny as far as I know. If you live in a cold climate (meaning 10 above zero and below) then a thinner (10-40) oil will get to the pistons quicker since it is thinner. Thereby, adding lubrication to the cylinder walls quicker and not causing as much abrasion. However, this is very minimal, but prevelant. Since the oil is thinner in cold weather, the car starts quicker since it turns over quicker as the thinner oil lubricates quicker. 

On the other side of the equasion, after initial warm up and in warmer climates, there is no real difference in the oils you have discussed. An oil with 40 in it should be used in more strenuous applications like very harsh usage (tractors - diesels (15-40)- high speed driving) and demanding applications. 

What you will find is that most new automobile manufacturer's recommend the 10-30 or 10-40 and if you don't use that grade, it can make a difference in your warranty. Otherwise, to cover all use conditions (normal, very cold, very hot), these oils give the best of both worlds.

A side note: If you have a car that uses oil and are using 10-30 as an example, I would switch to the 30 weight and it will use less oil because it never gets thin enough to escape down the cylinder walls as quickly and the extra viscosity seals better than starting a cold card that has thin oil in it.

Otherwise, if you car is not new, I would not worry about it too much. This is my personal opinion and my understanding of the issue.


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## batty_professor

I suspect you're asking about the straight 30 wt. due to an availability to you. Where you live and with your car, it's not much an issue, especially with warmer weather around the corner. Just make sure it doesn't say "non-detergent".


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## elf

Well my car was running low on oil, and I was just about to hit 3k miles so I filled her up and got it changed later that afternoon.


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## Guest

Hi,

There could be no damage at all from doing this. You did exactly what anyone would have done in that situation and it would not  have any adverse results for the engine.....even if you had run it for a long time before changing.


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