I recently had my diesel Range Rover sport serviced but the garage didn’t re-seat the fuel filter correctly causing a leak of fuel. At the same time, my engine light came on and it turned out to be clogged/faulty EGR valve. My question is, could the fact I drove several hundreds of miles with an unsecured, leaking fuel filter have caused the EGR failure?

  • Welcome to Motor Vehicle Maintenance & Repair! Dec 29, 2018 at 13:25

1 Answer 1


No, they are not connected in any way.

The EGR deals with exhaust gasses. They can, over time, get plugged with soot or possibly have a mechanical failure (depending on design). The EGR only comes into play after power generation, and has no connection to the raw fuel or fuel delivery system. Unless the leak was directly spraying on the EGR, there's no way a leaking fuel filter could have caused this issue.

  • Hi, thanks for your reply. Could the loose fuel filter not have caused an imbalance in the fuel/air mixture therefore causing the issue with the EGR? Or could it have allowed any other impurities into the engine?
    – Kieron
    Dec 29, 2018 at 15:00
  • If it were running slightly lean it would potentially run hotter than normal which may not have helped the carbon levels in the EGR valve, but that a really outside possibility and it would likely have just accelerated failure, not caused it completely. Dec 29, 2018 at 15:02
  • @Kieron - I really don't see how. It would have to be a HUGE leak ... one which dropped the fuel pressure enough to make it go lean ... the computer would have most like compensated for this. If the leak was large enough to truly make a difference, I doubt you would have been driving for a month as the smell would have been tremendous. Really, there should be no connection between what you describe and a faulty EGR. Dec 29, 2018 at 15:03
  • @Kieron - I did miss one thing, you stated it is a diesel engine ... this would most definitely rule out a fuel/air mixture issue from low fuel pressure. The fuel filter is between the drop pump and the high pressure pump. As long as the high pressure pump is getting fuel, it will pressurize the injected fuel to the proper levels ... no imbalance. Also, a diesel EGR is very susceptible to carbon clogging just by the nature of things (ie: how a diesel engine runs). No surprise an EGR might go bad there. Dec 29, 2018 at 15:07
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    Consider how you play hell with them - they may, or may not, accept you as a customer next time... “sorry fully booked next week” etc etc
    – Solar Mike
    Dec 29, 2018 at 17:39

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