GlenQ
Active Member
Just checked my air filters. The filter box was full of dead flies. The filters themselves did not seem too bad just a little discoloured. How do you really know when it's time to change them
A unit like this is used to monitor air filter efficiency on commercial vehicles;
ebay item 200622486388
Mercedes trucks used to have an indicator on the dashboard where a sensitive differentiual pressure gauge would reveal a red flag as the filter blocked. It probably wouldn't be too difficult to obtain one and use it - you could argue it would be a better use of dashboard space than the gimmicks usually found there.
Some Land Rover Defender diesels had a visual gauge in the engine bay (on the air filter canister) in the 1990's Tdi 200 models.