Have you ever recovered oil from an A/C system and the colour was ‘off’? Analysing the oil colour is an excellent way to help diagnose and trouble shoot, as the colour gives very clear indication as to what might be going on in an A/C system.

Whether you’re suspecting an issue or just want to do a system ‘health check’ as part of a service, a great and easy way of checking the oil colour, is by using a diagnostic sight glass.

There are many benefits in using a diagnostic sight glass. It will give you easy access to the oil colour and therefore can be an integral part in the diagnosis process. It will also expose contaminants and impurities, such as metal filings, that may be present in the system. Again, this may help in diagnosing the root cause of an issue. Picking up issues early will also help avoid damage and costly repair.

An added benefit is the ease of documentation, whether it’s for your own purposes or for your customer - simply take a photo of the sight glass window and add it to your report.

Using the sight glass is as simple as connecting the high pressure hose to the high pressure valve of the A/C system and filling approximately two thirds of the sight glass with the refrigerant-oil mixture. Then analyse the colour and look for potential contaminants.

Are you familiar with the cues that various discolouration of oil give you?