What is the point of changing fuel filters?

[Condi]

Now, hear me out on this one. Most service manuals say every 2 years or whatever it may be, change the fuel filter, but is this a total waste of money? I 100% believe that fuel filters do an important job and they must be in place but the amount of crap you find in any fuel filter is negligible at the replacement interval. Fuel tanks are generally clean these days - they don't rust, you don't get much crap in there when filling - and the tanks at the petrol station are cycled often enough that you get very little crap coming out.

I'm just contemplating this as I've realised my motorbike hasn't had the fuel filter changed in at least 15 years, and the bike still runs perfectly well. Part of the reason it's not been changed is that the part alone is £60, and to get to it you have to take apart the fuel tank as the filter and pump are inside the tank itself. Thanks Honda.

[J4CKO]

Yeah, changed a few and never really noticed a problem, cut a couple open and barely anything in them.

[cptsideways]

Until you pick up some contaminated fuel

[DaveCWK]

All my cars have had a basic gauze/sock type 'filter' directly on the fuel pump in the tank. It is this that captures ant tank rust flakes or fuel sediment or whatever if there is any.

I share the belief that the downstream fuel filter doesn't really do much. Generally they are cheap though so I do ocasionally change them

[RustyNissanPrairie]

Diesels pump the fuel to the HP rail then the excess back to the tank. Due to the reduction in sulphur - high pressure fuel pumps are prone to wear and in worst cases disintegration. This metallic swarf passes through the injectors and contaminates the fuel tank and entire fuel system effectively writing the car off due to the cost.

The fuel filter on my Cayenne 3.0 V6 (VAG) engine is 10k miles service interval. I change it every 5k miles.
At £20 for an OEM Mann filter it is cheap prevention and it also gives an indication of impending HPFP issues. It is also surprising how much water there is in the bottom of the filter housing.

Edited by RustyNissanPrairie on Friday 6th March 09:04

[OldGermanHeaps]

I have cut open diesel filters and found black debris in them plenty of times. I wouldnt like that in my hpfp.
When i had a peugeot expert i found bits of the hpfp in the filter.
Wtf was i thinking buying french over and over again?

[Ifinishposts]

[Watcher of the skies]

OldGermanHeaps said:

I have cut open diesel filters and found black debris in them plenty of times. I wouldnt like that in my hpfp.
When i had a peugeot expert i found bits of the hpfp in the filter.
Wtf was i thinking buying french over and over again?

When I had my 2.2 diesel Evoque every 2-3 years it would develop a very slight occasional hesitation. The garage changed the fuel filter every other year and said that they are sensitive to poor quality fuel. Maybe it's the French at work again on the Ford/Peugeot 2.2 diesel.
My wife's had 4 D5 Volvos which have never had any fuel filters changed, so make of that what you will.

[Hondapower]

I had to end a track day early as the car kept running lean. Turned out it was the 18yr old in tank fuel 'sock' that was clogged. I now change it every couple of years to be on the safe side.

[Belle427]

Recently changed one on my 2005 Merc C180K at 87k miles and it looked original, the crap that came out when I removed it was black in colour.
Some are a real pita to change which is why they never get done, for me if they are cheap enough to buy I will do it every 3 years on a petrol if it has one readily accessible.
Diesels I normally stick to every 2 years.

[LightweightLouisDanvers]

I change mine every other service so 20k mile intervals. Keeps the 2.2 diesel freelander 2 happy.

[the cueball]

cptsideways said:

Until you pick up some contaminated fuel

It's all good, right up until it isn't!


I had my Kawasaki supercharged engine destroyed by contaminated fuel.

[E-bmw]

Personally I tend to change fuel filter in the first service in my ownership & then probably if I still have it 3 years later etc.

[donkmeister]

RustyNissanPrairie said:

Diesels pump the fuel to the HP rail then the excess back to the tank. Due to the reduction in sulphur - high pressure fuel pumps are prone to wear and in worst cases disintegration. This metallic swarf passes through the injectors and contaminates the fuel tank and entire fuel system effectively writing the car off due to the cost.

Yeah, fuel return will contain the worn particles of the pump and so on. Too small to see but enough to build up and block the filter eventually. Is a 1 or 2 years replacement frequency overkill on a petrol engine? From my experience, yes.

From my own experiences, there's never anything visible in the fuel filter. I change them because you don't know until you change them.

I once had an inline one that was incredibly rusty, was probably 8 year old original at that point and I was worried it would hold and start pissing fuel on the ground. Despite the outside being decrepit there was no visible crud in the medium.