I do not know how it works but the bottles of def are dated and I think there is a 2 year shelf life on the stuff but does that mean it should be used and burnt by then?? If that is the case a low hour def machine is a ticking time bomb,I would think.
There should be DEF filters that are serviceable by you. Here is a link to the parts catalog:
Locate all parts and component information about your Bobcat equipment with detailed visual diagrams and illustrations with parts numbers and add to your list.
partscatalog.bobcat.com
Just enter your serial number and then search "DEF" this will give you all of the schematics and you should be able to find the filters.
I did some reading about DEF just out of curiosity and it seems that it goes bad pretty easily.
The deionized water will pull in contaminants from the air if the cap is not tight. Any contamination from funnels, dirt around fill hole, non original containers, etc. will cause problems. If the water evaporates the mixture ratios get off and it won't work. If it is stored in an improper container it will corrode the container contaminating the DEF. Temperature fluctuations will cause it to go bad quicker along with improper storage.
If you can see the DEF in the machine, or pull a sample out, it should be clear. If it is cloudy it is bad. All of the info on-line that I have read says that you need to check the fluid in the tank to make sure it is still up to spec. ( the ratio of deionized water to Uriah needs to be correct ). This requires a refractometer. It's similar to how anti-freeze is tested.
There is also the chance that one of the DEF sensors or pumps have gone bad.
Now I know why people are always looking to buy older machines that do not require DEF.
