Fuel leaks on an older car from Japan: what a viewing can show, and what to change after you buy

A fuel leak is one of the faults that matters most on an older car and shows least in a listing. Photos are taken from the outside, in good light, of the parts that look good. Fuel seeps out of the parts underneath and in the engine bay, and the first sign is often a smell, which no photo carries.

I've had it happen myself: fuel leaked from the fuel pressure regulator on one of my cars, and I thought it was going to catch fire. That's why, in my view, an older car should get new fuel and coolant hoses and a new fuel filter soon after you buy it, and a fuel pump that has never been changed may well fail.

How seriously a leak is taken

The UK's MOT test is a useful measure, because it sorts fuel system faults by how dangerous they are. In the DVSA's inspection manual:

Fault	MOT category
Fuel pipe or hose chafing	Minor
Fuel pipe or hose damaged	Major
Fuel system leaking, or missing or ineffective filler cap	Major
Fuel tank, pipe or hose insecure	Major
Fuel system leaking excessively, or a risk of fire	Dangerous
Fuel tank, pipe or hose insecure so that there is a risk of fire	Dangerous

The manual also says a tank or filler neck with a hole or split that fuel can leak from must fail for leaking, "even if the hole or split is above the fuel line". Other countries have their own tests. The MOT's list is simply a clear way to see that a leak isn't a cosmetic fault.

What a viewing can show

On an On-Site Vehicle Viewing, we photograph what can be seen without lifting the car or removing anything:

• Underneath, from ground level. Wet patches, staining or drips along the floor and around the back of the car, as far as they can be seen.
• The engine bay. An overview, including the area around the hoses and fittings we can see from above.
• The boot (trunk) floor and spare wheel well. On some cars, parts of the fuel system sit close to them.
• Smell. If we notice a smell of fuel, we say so in the report. It's our impression on the day, not a measurement.

Where a fuel tank sits above a cross member or behind panels, much of it can't be seen at all. The R33 Skyline GT-R is one example: its plastic tank sits above the rear member. More on that car in the R33 GT-R page.

What we can't tell you

• Whether the system leaks under pressure or when it's hot. We don't test the fuel system, run the car for long, or put it on a lift.
• The condition of the fuel pump, filter or regulator. Most of it is hidden, and how it looks says little about how long it will last.
• Where a smell is coming from. We note it. We don't trace it.
• Whether the car is safe to drive. We don't diagnose faults or say whether to buy.

If the dealer agrees and the car is somewhere we can reach, send us the listing and tell us if fuel is a worry. We'll photograph the underside, the engine bay and the boot floor as far as they can be seen, and tell you what we couldn't see.

Send us the listing link

What to ask the dealer before you buy

1. Has the fuel pump, fuel filter or any fuel hose been replaced, and when? Ask whether there are receipts or maintenance records.
2. Has anyone noticed a smell of fuel, inside the car or around it?
3. Close photos of the underside at the back of the car, from ground level, in daylight.
4. A photo of the engine bay, with the bonnet (hood) open.

Whatever the answers, in my view the hoses and the filter are worth budgeting for as soon as the car is yours.

A car a long way from the Tokai region (Aichi, Gifu and Mie)? A Remote Check is where we phone the dealer in Japanese, ask when the fuel pump, filter and hoses were last changed, and ask for photos of the underside before anyone travels.

Written by Yoshiaki Sagara, a paintless dent repair and detailing technician in Japan. He looks at cars for overseas buyers through Ninja Desk Japan. About us

Send us the listing link