Starting leaking diesel today.
Found where it was shooting out from, as show in diagram.

I'm by no means a car enthusiasts, so I have limited knowledge. Should I change all 4 fuel lines on that side? Or should I buy individual fuel lines?

I called around to get quotes, but some guy at Boener Trucks said he needed to know the engine model number. I told him it was a 1990 E350 7.3 diesel. He said that's not enough info. What's the engine model number?

 

I see no diagram

 

Are you talking about the injector return lines? The rubber lines that run between the plastic caps on top of the injectors?

If yes, you can just buy a length of diesel rated fuel line and replace them. However, as soon as you disturb the caps, the o-rings under them will start leaking (which might be whats leaking anyways). The o-rings are size 111 and should be viton. If you are careful removing the plastic caps, and they are intact, you can replace the o-rings and hose for cheap. Otherwise you can buy a kit that includes everything you need.

There are MANY threads on here about changing the return lines. Use the search and find them..... then do some reading up.

If the metal lines are leaking, make sure they are snug at the ends. They are a little pricey to replace. Best option is to find them from a junkyard. Make sure the injector lines have the metal clips that stabilize them installed. If they don't have the clips, the lines tend to vibrate excessively which causes fatigue stresses and failure.

 

I do not see any diagram either.

That guy @ Boner Trucks must be a real sharp tool. He can't figure out what diesel engine that is from a huge list of, uh, one that was used in the F and E series Fords for that year.

 

He probably meant (or quite possibly _said_) engine _serial_ number. The engine serial number is on the top of the block, driver's side, just aft of the IP cover, sorta between the IP cover and the intake manifold. IIRC, there were some subtle changes in the bends/shapes of the IP-to-injector lines over the years, so the Boner dude's book may list by engine serial number.

 

I'm just glad to hear that the fuel lines are shooting out diesel and not maple syrup or anything weird like that.

Sounds like a standard return line issue. If so, tecgod13 hit the nail on the head.