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Compressor oil


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Hello all,

 

I decided it was time to change the oil in my compressor (2.5hp. 25 liter tank Aldi, £80.00). Now the fun begins I can get 15/40 motor oil (mineral or synthetic for diesels), but not 15/40 compressor oil. Is there any big difference between the two, can I use the motor oil with no problems or will I have to fined compressor oil?

I can also get air tool oil but that is going to be different stuff.

 

Thanks,

 

OzzyO.

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I've topped up the oil in my Rotring airbrush compressor with 15/40 mineral motor oil with no ill effects so far. I have now got some compressor oil from Machine Mart but visually it doesn't look much different to the 15/40 oil.

 

Mark.

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Be careful - engine oil has detergent in it to clean up engines as well as lubricate. This action in a compressor can lead to seal failure - you at least need non detergent oil.

 

 

 

 

How do you tell?

 

OzzyO.

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How do you tell?

 

OzzyO.

 

You can't do your washing up with compressor oil?

 

Compressor oil is readily available such as this from Machine Mart.

 

I don't quite understand why anyone would not use the right thing for the right job, you wouldn't put light machine oil in a car would you?

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You can't do your washing up with compressor oil?

 

Compressor oil is readily available such as this from Machine Mart.

 

I don't quite understand why anyone would not use the right thing for the right job, you wouldn't put light machine oil in a car would you?

 

 

 

That's why I'm asking Phil. In my back water all I can get is motor oil. Guise it's on to Machine Mart for me.

 

Thanks

 

OzzyO.

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Just to adding a point, the SAE 15/40 oil is a multi grade dependant for it's rating on temperature additives, it will be a light SAE 15 at room temperature, rather thin for compressors, and would thicken only if the compressor reached engine temperatures. Anti foaming additive and detergent is added to multi-grade, but should not affect seals, as there are seals in engines, and they are usually the same grades used in compressors.

 

It is always best to use the right stuff, but the multi-grade 15/40 will work in most piston compressors without causing damage. If the maker specifies a much higher SAE single weight then the multi-grade is not a suitable substitute, they may say for instance, use SAE 50 oil, please note SAE 20/50 is not the same thing, it only achieves SAE 50 weight at high temperature.

 

I have an old Stuart Turner made compressor that specifies SAE 150, this is way higher than usual these days and it is run happily with SAE 100, rather than buy in the heavy Ford diesel rated lubricating oil. Older compressors used the heavy oil to achieve a good seal in the cylinder to save fitting multiple piston rings.

 

Stephen.

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Having looked at the replies, I'm getting a bit stuck as all the oils are single weight ether 30 or 40 none of them has any 15/40 so do I go for the straight 40.

Thanks to all who have replyed.

Pages from the manual attached.

post-8920-128074592188_thumb.jpg

post-8920-128074594489_thumb.jpg

 

OzzyO.

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I seriously think the maker is confused in the instructions, (perhaps in the translation), and means use car oil, as specifying a SAE oil is specifying a car rated oil, which is what SAE stands for.

40 weight straight oil is much heavier than most modern compressors use, and may induce a bit of drag. The 30w may be the best to go for if it is advertised as compressor oil, but I would not loose much sleep over this.

It is probably the anti foaming additive that the makers feel is important and that's why SAE 15/40 is mentioned. I have just phoned my local supplier, who does specialist oils for the workshop, and he says use the car oil!

 

Stephen.

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I read the small print in the instructions and found a help line number so I called it. The answer that I got was to use motor oil 15/40 grade.ohmy.gif So why say compressor oil in the instructionsscratch_one-s_head_mini.gif . Thanks to all who replyed.

 

OzzyO.

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I read the small print in the instructions and found a help line number so I called it. The answer that I got was to use motor oil 15/40 grade.ohmy.gif So why say compressor oil in the instructionsscratch_one-s_head_mini.gif . Thanks to all who replyed.

 

OzzyO.

 

 

Automotive oil viscosity is measured at different temperatures. What the multi-grade means is that it has the viscosity characteristic of a lower viscosity oil at the lower temperature (i.e. 15) and the higher viscosity at the higher temperature (i.e. 40). The oil does actually becomes less viscous as the temperature rises but not as quickly as a mono-grade oil.

 

Not that this has any bearing on the topic but I thought you might want to know!

 

 

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As I thought "lost in Translation" !!.... generally motor oil is tighter specified than plain single weight oils, and you can use them around the workshop without any problem, better oil than none!

 

 

One area not to use them in, and it does come up in our hobby, is they are no use with real steam engines, the temperature turns it partially to soap! Steam oil is a special type, and resists the wear better, and does not curdle or foam like lighter car oils.

 

Stephen.

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