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There's potentially water in my car's fuel tank. What should I do?

I left the fuel cap off my petrol Kia. I didn't find this out for 3 weeks whilst on holiday. Rain probably got into the fuel tank. What should I do?

Asked on 29 July 2021 by Barry Boyers

Answered by Dan Powell
To be on the safe side, I would recommend having the fuel tank drained and the fuel lines flushed. The water level in the fuel may be minimal but there is no real way of visually checking this as diesel is lighter than water (which means the water will be at the bottom of the fuel tank). If there is water in the tank then it could damage the injectors. Water can also produce bacteria, which forms an unpleasant sludge in the tank that will clog up the fuel filter.

A fuel drain will probably set you back £300 - £400 (or £700 - £800 via your Kia dealer). But it'll be cheaper than risking water damage to the engine and fuel tank.
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