by outbackjoe on Fri, 13 Jul 2012 5:30 +0000
The initial reason for this post was to ensure I interpreted the manual correctly, in that there is no scheduled maintenance to the filter according to the manufacturer. That has been answered, but the replies open up some questions regarding how often to replace it. I'm no authority on filters so I'm probably wrong but my thoughts are:
1. Usually, when there is technical disagreement between those that participated in the design of an item, and those that didn't, those that participated in the design are correct. When those that did not participate in the design raise a design issue or oversight, usually there is no issue. Not always - designers aren't perfect, but taking a bet when all other things are equal, you'd bet on the side of the designers. Actually this is a whole topic that I can go on about all day - "Those that participated in the design vs those that didn't"
2. Fuel quality issues in Australia are largely unsubstantiated in my opinion. Sure our spec is different to Europe, we have more or less sulfur etc, but that is unrelated to suspended particles and water which is what the filter is designed to capture. We hear stories of damaged injectors etc from poor fuel, but I'm not sure if that problem is specific to Australia.
3. Filters do not filter less when they become dirty. They still filter, but it becomes harder to pass fluid through - it starts getting blocked. This manifests itself as a pressure drop across the filter as fluid is forced through. In industry, filters in lube systems protecting large / expensive equipment are replaced according to a pressure sensor measuring the pressure drop across the filter. When the pressure drop is too high, it flags a "blocked filter" alarm and the filter is then replaced. I don't know what instruments are on a Hilux fuel filter, but it sounds like it could be a water sensor and a pressure sensor. In terms of the filter becoming dirty, the pressure sensor would activate the fuel filter indicator and you would replace the filter - consistent with what happens on industrial machines.
So in my opinion replacing every 10k is overkill. You could argue it's introducing risk of contamination for no reward. But we need to pick a value between every 10k and every time the filter indicator comes on - it's up to your personal preference and experiences.