AdBlue screw cap seized

[wild camper]

I tried to unscrew the AdBlue cap located below the diesel fuel filler today
It was seized, couldn’t unscrew it by hand, fortunately I was in my garage with my tools available, it took a large pair of grips to release it
I was concerned that I would crack the plastic cap
It’s been about 5 months since I poured any AdBlue into the tank
There were a lot of white crystals formed in the cap threads
Also the cap on the AdBlue container needed the grips to unscrew it
I’m glad I found out at home and not on the road when the warning light came on
I’ve cleaned off the crystals and applied petroleum jelly to the male and female threads
It may be worthwhile you trying to release it

[blue estate]

That’s why most truck Adblu caps are bayonet type lockable cap not screw on


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