Filter facts
Time certainly seems to move very quickly these days and with several vehicles in the Dodgy Bros fleet, we always seem to be behind in their servicing, even though we think we are on top of it.
I was doing some maintenance on my LR90 and giving it a service at the same time recently. I gave it an oil change using a genuine oil filter, as I tend to do for most of my vehicles and thought it must be time to do the fuel filter as well. Now I don’t tend to change this every service but didn’t realise how long since i t was last changed. When I went to change it, I realised the filter was still the same one that was still in place from t wo years ago. The reason why I knew this was because i t still had the bolt in the bottom that was a temporary road side fix when the plastic filter drain plug was leaking and broke when I touched it.
Sitting on the roadside with a filter that wouldn’t hold fuel meant you weren’t going anywhere until the filter was either replaced or a fix was found. In this case a fix was found in the form of a small bolt that had the correct thread to screw into the filter. Once home, the filter would have to be replaced.
Here I am going to change the filter and come to the sudden realisation that I had not replaced i t since before the roadside repair. A check back on trips and dates and i t is even more of a surprise that it was now over t wo years since that trip.
Needless to say a new filter was fitted but it got me thinking about how often others check and replace their fuel filter, especially on the more modern electronically-controlled engines these days.
Because of extremely fine tolerance, diesel vehicles should have their fuel filters changed every year or t wo at the most depending on the environment it has been operating in. The filter is the line of defence against debris and small particles of rust etc from inside the fuel tank getting through and clogging and/ or premature wearing of the injector pump or injectors. It pays to check the manufacturer’s service schedule for your vehicle and follow i t religiously.
On the subject of filters, what about the
air filter? How often do you check that and clean i t or replace i t . Personally I stick to the OEM paper filters and am prepared to replace them weekly or monthly if doing a lot of driving in dusty conditions, such as convoy work on tagalong safaris.
As well as the paper-t ype air filter there are oil foam and cotton filters available which both are washable and able to be re- used. Oil foam filters use t wo layers of open cell foam which is soaked in a special blend of oil to catch contaminants before they are sucked into the engine. Sometimes these are referred to as highflow filters because the design offers less restriction than standard.
Cotton filters use multiple layers of pleated cotton held in place with mesh and the cotton is also oiled to increase filtering.
I have a dislike for both of these t ypes of filters because they are less restrictive and not ideal for the dusty and muddy environment in which we tend to operate our vehicles. Secondly is the fact that people don’t tend to service them regularly enough. Being oil and dirt it’s a messy and time- consuming job to clean in kerosene, dry and re- oil them properly and people just don’t do i t enough.
Another reason why these t ypes of filters aren’t particularly good is that some t ypes of oil used to service them
can contaminate air intake sensors in a modern vehicle. This can be especially troublesome in some common- rail diesel engines where anything that interferes with the engine’s fuel/ air ratio can cause major mechanical problems.
A decade or so ago we operated a vehicle with a high- flow filter, that wasn’t serviced regularly. In a short space of time we were getting the engine rebuilt and at the time the engine builder said the inside of the engine was ‘ dirty’ and worn throughout. It was put down to the t ype of air filter we were using that let dust particles through.
What happens when an air filter starts getting blocked is the increased suction by the engine seeking air, tends to suck through the very fine dust in the unblocked parts of the filter, the very fine dust that you want to keep out of your engine. And that fine dust will destroy an engine in a very short space of time.
One thing that can extend the service life of your air filter is the fitment of a raised air intake ( RAI) or more commonly referred to as a snorkel. But even then not all raised air intakes or snorkels are equal, so again i t pays to get a good quality one.
OK, for me it’s back to the workshop and to check what other vehicles and their filters are overdue for replacement.