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Basic Oiled Air Compressor Maintenance

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Like any other tool, air compressors require a little TLC to keep them in good running order. We’ve put together a list of basic DIY servicing and maintenance you can do to keep your set up running efficiently for as long as possible.

By performing a little maintenance, you’ll keep you down your energy consumption and therefore costs and extend the life of your compressor and anything attached to it. It’s the beating heart of much of your fossil preparation set up - give it the life it deserves! Compressed air isn’t free, but there are some steps you can take to make it cheaper.

For all of the below, make sure the tank is not pressurised and that your compressor is unplugged from the mains.

READ THE USER MANUAL. Yes, we know, it’s boring and technical. But the best way to maintain your compressor is not to exceed its limitations. It’ll give you the lowdown of all the things we describe below which vary from model to model. It’s also to your benefit - you might accidentally void you guarantee. Nothing kills a compressor faster than somebody who ignores the ‘fluffing instructions’.

DRAIN! DRAIN! DRAIN! Your compressor is taking in an awful lot of air from the atmosphere, and with air comes moisture (especially here in rainy England). Once it reaches the tank that moisture condenses out and will pool at the bottom. The more humid the climate, the more water you’ll accumulate. Simply put, water is BAD. Bad for your compressor, and bad for your tools. The water will rust the inside of the tank, gradually thinning the metal where the water has pooled, and eventually it will explode. At the working end of your lines (i.e. the tools) a sure sign of too much water in your tank is the occasional spurt of blackish oily liquid all over your lovingly prepared fossil. Along with the oil and muck, come bits of rust which can eat away o-rings, clog up the small valves in the body of the Pusher Plate tools, the air galleries of the Impact Driven tools; and an air abrasive unit will be rendered no more than a decorative item (it just won’t work).

At the end of the day (EVERY day!) drop the pressure to below 1 Bar in the tank either by running your tools with the compressor switched off or using the safety pressure release. At the bottom of your compressor, you’ll find a small brass nubbin known as the drain valve. Reach under the tank and gently unscrew the drain valve making sure to hold it tightly so that the remaining pressure in the tank does not blow it out of your hand and into some dusty corner of your workshop. Any water and gunk will come rushing out into a (hopefully) neatly placed tray. Put your drain valve to one side until the following day allowing the condensation on the sides of the tank to drain out overnight. When you next use it, tighten up the drain valve (finger tight will do the trick) and off you go.


Just like a car or a motorcycle, your air compressor needs oil to live a long life and to run efficiently. The oil lubricates the inside of the pistons which compress the air and push it into your tank. Refer to the user manual to check any type and viscosity specifics for your model, but most general ‘compressor oils’ will work just fine.



Topping up the oil. The most common thing you’ll need to do is top up your oil; just check the level through the oil window or using the dipstick once a week, and if it seems to be running low, pour in some more. There will be some sort of marking that indicates the maximum level the oil should reach. From personal experience, we have found that overfilling with oil is a quick and easy way to get that Jackson Pollock look on your ceiling. Trust us, it won’t save you time.

Oil changes. Ideally, you’ll want to do this about every three months, but you should be doing it at least once a year. Most manuals will say every 12 months or 500 hours; whichever comes first. Oil gets pretty manky after a while, and you want to be lubricating those pistons with the lovely, clean, fresh stuff or you’ll significantly reduce the lifetime of your compressor. Nobody really keeps track of how many hours they’re using their compressor for, so it’s better to change the oil too often rather than neglecting it. Black oil through the oil window means it’s too late. You can always get a vibration-activated hour meter if you think you’ll forget.

Unfortunately, most compressors do not come with an oil draining valve. Therefore, you’ll need to get yourself a syringe with a piece of hosing and suck out the gunky oil from the oil reservoir. You’ll have an easier time sucking it out if it’s warm. Then just carefully replace the oil to the maximum level.


It’s really important to clean and check your air filters at least a couple of times a year. Fossil preparation is dusty work. You’ll need to clean out or entirely replace your air filters every now and then (usually recommended every 50 hours), but obviously you’ll be dong this less often if you use an efficient dust extraction system or contain most of your dust and dirt in a blast cabinet. If you’re forcing your compressor to take in dirty air, it will compress it much less efficiently and your tools won’t work as they should and will eventually be degraded.

On the side of your motor will be a plastic cup-shaped fitting with a pipe running from the side of it. That is the air intake for your compressor. When you install this component, make sure that the pipe is pointed downwards so that less dust gets in in the first place (gravity is our friend). Usually there are little tabs which enable you to pop the cap off, revealing the air filter inside. It should be pretty obvious if it’s dirty. Give it a good clean with compressed air. If it’s really bad - replace it. They’re cheap. Cheaper than new compressors.


Compressing air is a very jiggly job. Some of the fastenings and fittings on your compressor might come a little loose thanks to all the vibration. You might hear a new rattling sound if you’ve left it a bit too long. At least once a year, go through every nut and bolt on your compressor and tighten it up with a spanner (righty tighty, lefty loosey style). Don’t go 200-pound gorilla on it. If it feels tight, just leave it.


Cheaper compressors usually have plastic or rubber hoses running from the motor to the tank and to the air outlets. These are the veins of your compressor, and need to be checked frequently for wear and tear. If you see that they are cracked or damaged, or even leaking, contact the manufacturer and order some replacements. Hire in a professional to do this, and only attempt as a DIY job if you’re really confident and know what you’re doing.

We recommend getting a professional in to service you compressor once a year; to check your motor and pistons are running in order or in case you need any spare parts.

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