Compressor oil

[fizzy]

I am not normally so fussy but as I have a nice newish Clarke 30cfm 3 phase compressor I wanted to make sure it had the correct oil.

I ordered some ISO100 compressor oil. Is it supposed to be so thick? Like treacle or golden syrup - and the weather is fairly warm at the moment.

I hate to think what it will be like in Winter. I am sure a multigrade car oil would be far better.

Anyway it is done now - so back to my question - is ISO100 oil very thick or have they put the wrong one in the can?

 

[Seadog]

ISO 100 is equivalent to SAE30 (which means more to me, like Imperial and metric). It should be a free flowing oil. BTW, compressor oil is simply an additive-free motor oil.

If you use a normal motor oil you will get significant carbon build up since compressor heads can, and do, run very hot.

 

[fizzy]

ISO 100 is equivalent to SAE30 (which means more to me, like Imperial and metric). It should be a free flowing oil. BTW, compressor oil is simply an additive-free motor oil.

I put iso32 hydraulic oil in by mistake - that was far thinner - then had to drain it out when I realised my mistake.

SAE30 would be similar to normal car engine oil I would have thought but this stuff was quite a bit thicker - took ages to fill through the pipe I borrowed off my used oil sucker. Not the narrow bit for the dipstick but the larger bore section.

 

[daleyd]

Is there any problem using ISO 32? I got some ISO 32 for my lathe and was going to use that in my compressor as well - I think the compressor oil you get from Screwfix etc is ISO 32.

https://www.screwfix.com/p/pcl-iso32-compressor-oil-1ltr/893hy#product_additional_details_container

https://www.toolstation.com/compressor-oil/p94582

 

[fizzy]

Is there any problem using ISO 32? I got some ISO 32 for my lathe and was going to use that in my compressor as well - I think the compressor oil you get from Screwfix etc is ISO 32.

https://www.screwfix.com/p/pcl-iso32-compressor-oil-1ltr/893hy#product_additional_details_container

https://www.toolstation.com/compressor-oil/p94582

Well that is where I went wrong.
After filling I saw Clarke says to use iso100.
Far too thick in my opinion unless you live in Australia or Saudi Arabia!

 

[fizzy]

In fact when Winter comes I will change it for a quality synthetic multigrade car oil. No way will the compressor like starting at 4C with that treacle it it.

 

[RWD3M]

I am not normally so fussy but as I have a nice newish Clarke 30cfm 3 phase compressor I wanted to make sure it had the correct oil.

I ordered some ISO100 compressor oil. Is it supposed to be so thick? Like treacle or golden syrup - and the weather is fairly warm at the moment.

I hate to think what it will be like in Winter. I am sure a multigrade car oil would be far better.

Anyway it is done now - so back to my question - is ISO100 oil very thick or have they put the wrong one in the can?

Hi Fizzy,

I just use Clarke SAE40 Compressor Oil from Machine mart in my Clarke XE29/270.

Never had an issue, had the machine 11 years and no problems starting or overheating.

 

[Al Strachan]

i have a few small compressors, sealey, clark etc. Clark recommends SAE40, Sealey SAE20 and they are essentially the same units give or take.

Being up here in NE scotland they can really struggle to start in the depths of winter, so i'm slowly changing all for SAE20.

 

[carbon]

I have some hydraulic oil that has 100 on the side of the drum but doesn’t list iso rating on it, I wouldn’t want to put that in a compressor as it’s way to thick for that

 

[fizzy]

I have some hydraulic oil that has 100 on the side of the drum but doesn’t list iso rating on it, I wouldn’t want to put that in a compressor as it’s way to thick for that

I bet it is iso100 - and yes it's thick stuff!

 

[Kram]

Someone explained to me that its worth using the correct oil, there will be hot oil vapour in the reciever and if it has lower temperature rated additives and oils in it, it would be a bomb.
So do not reuse old engine oil, which may have some petrol in it !

 

[carbon]

Why would you put used engine oil in a compressor that you plan to keep?

 

[daleyd]

Someone explained to me that its worth using the correct oil, there will be hot oil vapour in the reciever and if it has lower temperature rated additives and oils in it, it would be a bomb.
So do not reuse old engine oil, which may have some petrol in it !

None of that really makes sense to me - a compressor is a simple splash lube system, if you have oil bypassing the rings from the crank into the piston and receiver in any great quantities (going from low pressure area to high) then things are seriously wrong. Compressor oil is about the cheapest stuff going so there will be no special additives to stop it going bang.

I’d agree completely about not using used oil though - esp when normal stuff is cheap enough and lasts ages anyway.

 

[Seadog]

So do not reuse old engine oil, which may have some petrol in it !

Do not use engine oil, used or otherwise. You'll end up with a lot of carbon build-up.

 

[I/Mx]

I am glad to have found this thread but I am still confused.
As mentioned above, screwfix and toolstation both sell ISO 32 and halfords sell SAE 40

living on the South Coast, which oil do I buy ?

 

[northwest]

Compressor oil is about the cheapest stuff going

Well, not if it is for HPA it isn't. Coltri oil HERE a very reasonable £34 per litre plus post or one of the ultra quiet dental compressors, they know how to charge for spares!

 

[premmington]

Many new piston compressors are recommending a standard 10/40 synthetic engine oil.

Really...

I thought compresser oil was detergent free - if you use modern engine oil it all has detergent in it - and it will absorb the water and go "white" - emulsify...

I can see the thinking with using a multigrade - for cold starting...

If you really look at the sight glass on a big compressor on a cold day in the winter before a start up - you can see a white line on the glass just above the oil where the condensation sits before it gets "burnt off" - dispersed by the heat of the air head.

Both my Hydrovanes have timed electrical heater pads on the air head sumps for cold winter morning start ups.

Emulsifying oil in any low use compressor is a problem - even using non detergent oil. Compressors need to run and get really hot. I often just let mine run instead of cycling it on a pressure switch for this very reason.

 

[MCKDAVID]

....Compressors need to run and get really hot. I often just let mine run instead of cycling it on a pressure switch for this very reason.

+1 I do the same, every couple of weeks or so depending on heavy use, will open the external drain valve and just run it steady for a while until its good and hot...

 

[Seadog]

I thought compresser oil was detergent free

They definitely should be. The additives can burn and coke up the cylinders and valves.

 

[daleyd]

Well, not if it is for HPA it isn't. Coltri oil HERE a very reasonable £34 per litre plus post or one of the ultra quiet dental compressors, they know how to charge for spares!

Yes, obviously any specialist compressor oil is bound to be expensive but I was talking about your run of the mill standard piston compressors which the OP mentioned.