7.3 fuel leak...solved

[KlutchInd]

Well like many 7.3's I've got a fuel leak. Bought a new housing from DieselOrings a while back (overkill likely but figured if I'm there why not). Finally got it inside to start pulling it apart. And while pulling it apart it seems that the leak is coming from one of the fuel return hoses where it connects to the FPR (not seals in the housing). My question is where do those go? They're cheap to replace but wondering how much I have to pull out to do it. It's a 98 btw.

 

[Bikersmurf]

Is it one of the hard lines or a rubber hose?

When I Re&Re my fuel bowl there were short rubber lines to connect the rigid lines to the fuel pump and the fuel bowl. From there they do to the fuel tank. If I recall correctly there’s a junction on the inside of the frame rail where the box meets the cab.

 

[KlutchInd]

Its one of the rubber hoses. Looks like the fitting failed and was leaking there.

 

[Bikersmurf]

I think mine just has rubber fuel lines with regular screw type clamps. All my lines were cracking from age so I replaced them with fuel lines rated for bio fuel to be safe. I don’t envy the task you have ahead... they were a pita.

While you’re in there, make sure the schrader valve on the side of the fuel bowl is tight... they’ll make a huge mess if they come loose while driving. I ended up having to have a full Comercial Vehicle inspection because of the leak... even though there was nothing else wrong.

 

[KlutchInd]

I bought the whole fuel filter housing, I think that's on there. I also ended up ordering those rubber hoses with the clamps. The leaking hose came off the FPR and goes to the head from what I've been told (one on each bank). Ordered replacements for those. Now the question is getting to them. They're behind the alternator and the AC compressor. Wondering if I should just remove the radiator and core support to get in there. Never done more than filters on this rig so I don't know yet.

 

[eblau]

I just did this exact repair on our 96 7.3, the drivers side fuel line is accessible without removing that but I had to take a 9/16th wrench, cut the head off then weld the handle back on almost a 90 degree angle. It was very tedious trying to spin the first thread or so but then it just came right off.

I bought the whole fuel filter housing, I think that's on there. I also ended up ordering those rubber hoses with the clamps. The leaking hose came off the FPR and goes to the head from what I've been told (one on each bank). Ordered replacements for those. Now the question is getting to them. They're behind the alternator and the AC compressor. Wondering if I should just remove the radiator and core support to get in there. Never done more than filters on this rig so I don't know yet.

 

[KlutchInd]

So good news and bad news then. Thanks for that. I'm going to replace both hoses and the entire filter housing. Should I consider replacing the serpentine belt while I've got things apart. And how much do I have to remove to get that out?

 

[eblau]

how much do you have to remove to get the fuel bowl out?

 

[KlutchInd]

Not sure yet. I think I can get the fuel bowl out without removing the alt and ac compressor but its not going to be easy. When I couldn't find the ends of the fuel hoses I figured maybe I should just pull them both.

 

[Bikersmurf]

how much do you have to remove to get the fuel bowl out?

Dog house, air cleaner, air intake hoses, turbo heat shield, intake resonance box... then it’s a major pain to reach it all blind.

I didn’t take out the turbo, but it might help.

 

[eblau]

Sounds like fun on a van! The fuel bowl removal on our truck was about a 15 minute job but you can access everything easily from the front.... hope it goes well for you.

 

[KlutchInd]

That's where I'm at now. Got all that stuff out and haven't had time to continue. And yes it looks like a major PITA to reach everything without removing either the turbo to come at it from the rear or alt/ac to access from the front.

On a side note I found another leak. Transmission cooler, not sure if its the hose or the body yet but its right where the hose clamps on.

 

[truck mechanic]

Pretty sure those are the oil lines for the hpop system..... should have oil in them not fuel. but if they are leaking better to change them now,

 

[TomsBeast]

I've been chasing leaks on my '96 7.3, just had the HPOP oil reservoir off which was leaking from it's base.

As bikersmurf said, Dog house, air cleaner, air intake hoses, turbo heat shield, intake resonance box... then it’s a major pain to reach it all blind. You really need as much room as you can get from both the radiator side and doghouse sides as you can get. remove the passenger seat, 4 bolts. I wound up disconnecting the electrical junction and bugee cording the harness aside, bungee cording the upper radiator hose aside as well to give myself more room. Removing serpentine belt and alternator requires a tool I rented from O'Rielly's (15mm socket on a long flat bar to take tension off the tensioner). Once the belt is off, the alternator is just three bolts, the positive cable, and a connector, worth it to get a little more room IMO. A 3" inspection mirror and a couple well placed lights are your friend, as is a magnet on a an extension if you drop a bolt, and a step stool. Deep breathing and decaf coffee.

As I look at it, I see why a lot of the truck guys move the fuel filter bowl out of the valley completely and down to the frame rail, which eliminates 5-6 possible leak paths, and makes a 7.3 van filter change a snap, vs removing the air intake system and heat shied.

I did my trans cooler lines 2yrs ago, I removed the grill and radiator, replaced all the rubber hoses and the OEM 20yr old radiator while I was at it, one of the tank seals was weeping. The radiator hoses too "while I was in there".

Good luck!

 

[KlutchInd]

Thanks for that Tom! Hoses just came in today but I gotta go out of town for a few days. Hopefully get to working on that some time next week. I have a lot of "while I'm in there" projects going through my head, like radiator hoses and serpentine belt.