We’re preparing an in-depth review of our Isuzu D-Max Utah truck, so you’ll see how good we think it is when we publish that article. The truck has been very reliable so far, but we have encountered issues with the fuel filter warning light coming on.
The truck had only done 8,000 miles when the issued raised its ugly head. The amber fuel filter warning light started to come on intermittently at first. We thought it may have been faulty so it was ignored for a while. It was only when the light was on most of the time that I contacted our dealer – Roger Young in Saltash, Cornwall – to see if there really was a problem.
With their usual efficiency, they booked the truck in for a filter change straight away, so I took it in expecting it to be fixed under warranty. With the Isuzu being so new, I thought that the problem must have been caused by a faulty filter or something like that.
No, the technician at Roger Young changed the filter and then patiently explained that it had been working properly and that we must have filled the vehicle with contaminated diesel, maybe even from our own storage tank (we don’t have one!). It therefore wasn’t covered under warranty, as it was a problem that we had caused.
Reluctantly, I paid for the repair and vowed to only fill the truck up at busy petrol stations, which are not likely to run their diesel tanks dry, possibly allowing sludge to be dispensed with the fuel.
That was four weeks ago.
You’ve guessed it, the fuel warning light has started to go on again. As before, it started intermittently, but is now on for most of the time. Time to contact Roger Young again, but this time I was determined to sort this out under warranty as there is something clearly wrong either with the filter or the warning control system.
Well, it turns out that there is a problem that Isuzu know about. Apparently the filter is too fine so it filters out more than it needs to and gets clogged up far too easily. Isuzu are covering the problem under warranty.
So the vehicle is booked into Roger Youngs again. They can only replace the fuel filter with the same model that has the inherent problems, so it is only a short term fix, however they are speaking to other dealers to see if they have found a more permanent solution.
Hopefully, Isuzu have set the wheels in motion to redesign the fuel filter so that this issue is fixed once and for all.
So if you have one of the excellent Isuzu D-Max trucks and you get that dreaded fuel filter warning light coming on, don’t be talked into paying for a replacement. Isuzu are accepting that this is covered by warranty.
I’ll update this post when we get the filter replaced, and when we know what the long term fix is. In the meantime, feel free to post a comment below about your experiences with these faulty filters.
Important Update 16 March 2013
Our Isuzu D-Max has now had its first service and the fuel filter issue has been rectified permanently (hopefully) under warranty.
Isuzu have investigated the problem and found that the high bio diesel content in UK fuel increases the viscosity of diesel and reduces the flow through the filter, triggering the warning light.
This is fixed by the dealer replacing the whole filter assembly which now warms the diesel up to 55 degrees as it passes through the system, thereby reducing the viscosity of the fuel and increasing its flow rate.
Apparently this is affecting Isuzu trucks and lorries too.
So if this is happening to your Isuzu, get the fuel filter assembly replaced under warranty as soon as possible.