Changing Oil on Air Compressor

Should I change the oil of my compressor that has been sitting around for more than 4 years?

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Hello everyone I'm new here. I hope you can help with my dilemma. I have an Iwata Hammerhead Shark compressor. 1/2 HP. I bought some time ago. I can't say exactly when, but the last time I used it was around 2010 maybe. I didn't use it often then, but for a few projects. I had an older larger compressor that failed before that. So I bought this one afterward and it's worked great, but I stopped using it mostly because I was starting to do a lot of more commercial work digitally.

So now I want to get back to the traditional airbrush because I want to do more traditional work even thought the computer is still my tool of choice for preparing art and final editing of images.

So the compressor sat around for 4-6 years while traveling across the country (from Miami to Minneapolis) and now I want to try it out again. It has the original oil I used before and it's pretty clear.

Two questions:

1) Should I change the oil?

2) How do I do it? I have the manual somewhere and none I can find online. I will try and find it and see if it says anything.

3) I have oil I bought around the time I purchased the compressor. Does it go bad? It's got that like brown/yellow look to it.

4) When should someone change the oil in a compressor?

Any help in figuring this out would be very appreciated.

IMG_0279b by Luis Diaz, on Flickr

IMG_0277b by Luis Diaz, on Flickr
Here is the link for contact from the website... To receive a copy of the Hammerhead parts guide by fax, call customer service at 503.253.7308.
Looking at the oil level and the color of the oil I would say your good to go Oil go's bad from use as it pick's up small shaving and junk and additives in the oil get heated and used up.(sitting on a shelf won't do it)
I would have to agree w/ basepaint the oil looks ok for that long of a period if your thinking of using it soon I would just keep an eye on it for a bit just
to make sure things are still working the way it was when you put it away .just sayin.
In my opinion the oil looks good. My grandpa says "Don't touch a working machine!"
The airfilter is more important.
I mean the compressor itself needs a cleaning! :D
Thanks everyone for your comments. Very cool. I can rest a little easier knowing I can work on my art with my airbrush and compressor. Time seems to fly way too fast. Time to dust off the old compressor and airbrushes.
There are three main problems with older oil.

1. The viscosity increases over time (usually a bigger problem with conventional/natural oils, not as bad with synthetic oil).
2. The additives in the oil break down (true for both conventional and synthetic oil)
3. The oil gradually gains metal particulates from wear and tear that can consequently increase the wear and tear on a motor over time.

Oil viscosity reduces as the oil tempurature increases, but the problem is that old oil is still thicker during the first minutes of run-time before it's warmed up. Because of this, there is less oil lubricating the internal components of the motor at start up, with less and less oil lubricating the motor at startup over time, as the oil and/or additives break down.

Its not too expensive to just go ahead and change the oil, especially if you don't know how used/old the oil is. Its probably worth noting that my experience is primarily with respect to automotive oil (worked in a garage for years), so I cannot swear to how applicable that information is to oil in a fridge style compressor.

Still, better safe than sorry! :)
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Personally, given the cost, if its been sitting there for 4-6 year I would buy some new oil and do an oil change.

Don't see what's to loose.
the original poster hasn't been back since asking the question, but for future reference, if you're not going to use compressor for a week or more, undo the drain plug on the air tank, it will help stop moisture building up.
I'm with Chris, I would have changed the oil.