Fuel leak from....glow plug?

Trucks been sitting at home while I work on getting my own authority. Drove my truck to a dealership last week to buy a trailer and let it idle while there since it hasn't run for a few weeks.

After about an hour I found a large puddle of diesel on the ground and it was dripping off the engine like a leaking toilet. Maybe half a gallon to a gallon per hour. Luckily not the turbo side.

Anyway, made the short drive back home and decided to investigate today. Found the leak right away. Big bolt on the block leaking fuel.

Any of you experts know what it is? Injector? Glow plug? I'd try tightening it but will have to take off some stuff in the way first.

Paccar mx13, 2016 t680

 

Think you're right, gotta be a sensor. It's the only one of those things on that side of the engine.

 

Gotta figure out how to get the darn thing out. Finicky locking nut connections.

If I can get the sensor off, I can use a large socket to remove or tighten the bolt and replace the seal/washer.

 

Ended up having to use some channel lock plyers to get it started and it came right out. Washer crumbles like wet tissuepaper.

Replaced the washer with a new one from auto zone and so far it is holding. Going to idle the truck for half an hour or so to make sure it stays holding when the engine warms up and give it another tighten.