2017 Nissan Navara EGR valve

[FMS Ltd]

My 2017 Nissan Navara has just done 110,000 miles and the EGR valve has failed leaking coolant into the engine and potentially destroyed it. I already have a £2000 bill from Nissan and now i've been told the next move is to remove the engine to check it over. It's within the 5 year warranty but outside the 100,000 mile warranty. That's a risky component to fit to a vehicle and warn owners to be careful when their Navaras get to that sort of mileage. Bit of a nightmare really!

[Trevor]

I would imagine unless the coolant all dumped at the one time into the engine then it would have gradually been introduced into the combustion which at minimum have created a fine mist which would be burnt in combustion.

Has it mixed with the engine oil?  Does the engine misfire?

Water injection in diesel engines is used efficiently to produce power and lower emissions so the pistons would show as cleaned (almost steam-cleaned) and no further damage
Too much water then this can erode the aluminium pistons and even the valves

I would ask whether they could use a non-intrusive method of inspection such as a boroscope inspection through the injector or glow plug holes or even through the inlet or exhaust ports (manifolds removed)
Alternatively, they could run compression checks on the cylinders to see is there is any loss on one or more cylinders which would indicate damage has occurred