Help! Major Diesel Leaks

[UMR_Engnr]

I bought a 1989 F350 about a year and a half ago and it was leaking out of one of the injector return line caps. I let it sit for a few months and then started it up and then every injector cap was leaking as well as a few other spots in the fuel filter assembly. I had no idea how the leaks had gotten that bad, but figured it had to do with being old and sitting for a little while. I haven't been driving it, just starting it every once in a while. I wanted to start driving it so I decided to replace the return lines and fix the leaks. I replaced the return lines about three weeks ago, and it was pretty uneventful. After doing so I started the truck up and I didn't see any leaks out of the injector caps. I did still have leaks in the fuel filter assembly so I ordered a new style fuel heater and fuel olives. I replaced all that today and when I started it up all the injector caps are starting to leak like crazy again. Does anyone know what the heck is going on? My only guess is that the return line to the tank is clogged and causing the pressure in the return line to increase until it just leaks out the caps, but I don't even know if that is possible. Any help would be appreciated in how to solve this issue. Thanks.

 

[Wyreth]

A clogged return line is possible, and would cause the symptoms you're having. You can try disconnecting your return line where it connects to the T at the back of the engine, and blowing compressed air down it. That will often clear a light plug. It will also tell you if it is clogged or not.

 

[Hydro-idi]

You also need to put vasoline on the injector o-rings and caps before installation. Failing to do this step may cause o-rings to tear once you press the caps onto injectors. Also, cheap return line kits can leak too. Typ4 has an awesome return line kit that works well. I have bought a kit from him.

 

[tbrumm]

And also carefully inspect the the caps for burrs or rough spots in the plastic. The other guys on here warned me about that when I was changing my caps. Those burrs can nick or tear the orings.

 

[riotwarrior]

All of the above is good info...

inspect caps for casting flash parting flash what ever you want to call it. Carefully trim it out then sand slowly with finer and finer sand paper to smoothen it out.

When installing the O rings, install the top one first, then ROLL the bottom one past that one and into place. Use vaseline or some light grease on them and lightly coat them.

when installing the caps there should be a CLICK heard/felt, if not take an old o ring install ON TOP of cap and tighten injector line down to seat the cap.

For good return sets, contact Typ4 here his name is RUSS, he is away IIRC for a while...back after Christmas.

you may not have a blocked return line but maybe the FSS is not seating correctly.

Anyway do the above and see if that cures what ails you if not have a hot rum...that's not gonna fix the truck might make you feel better though.

JM2CW

Al

 

[UMR_Engnr]

Thanks for the help so far. I followed the general procedure outlined by many of you here. I probably could have paid a little more attention to the flashing. I'll shoot some compressed air down the return line to the tank tomorrow and see what happens. I really don't want to have to do it all over again. What a pain.

 

[GOOSE]

Everything so far is spot on. Could the fuel tank selector valve be hung up and causing restriction on the return side?

 

[UMR_Engnr]

Well, I disconnected the tee and shot some compressed air through it. It definitely seemed like the line was clogged because it took several good blasts before air was actually freely flowing through the line. When I connected everything again there was still some leaking out of the injector caps and the truck was putting out quite a bit of white smoke. Any more ideas. Thanks.

 

[UMR_Engnr]

I was doing some more research and word on the interwebs is that the Pensacola return line kit is not the best quality, and I believe that is the one I bought. I might just order a kit from Typ4 and redo it. Does anyone know if there are advantages or disadvantages to the early style return line routing/caps vs the late style routing/caps?

 

[Wyreth]

Preference from what I hear. Myself I prefer the early style, and don't see a reason to change it. No silly 3way cap, and I like the dedicated return for the IP.

 

[Mulochico]

If you pm Russ (type4) he will get back to you when he is back after Christmas. Let him know the year of the truck and he will set you up with the right kit.

Got mine from him in Feb. Great service, available for info when needed, and above all ..... Superb quality product!!!!!

If previous members problems with Pensacola is any indication, I think you will be very satisfied with Russ' kit.

 

[RLDSL]

I noticed recently when doing some work and we had remnants of one of Russ's kits, he uses the good German braid hose, and lots of kits use the 'merican hose, there is a HUGE difference in quality here. The German stuff will remain pliable and hold it's seal throughout it's expected lifespan, while the'merican stuff will dry up in short order and get VERY hard and cause air leaks. I just ran into this very thing recently on one of my European diesels where I normally get the German hose at the local injection shop and they sold me the 'merican stuff last time. It only lasted a couple months before it started having starting problems, the hose I pulled off teh engine was bone hard brittle. Getting quality return line makes a world of difference

 

[UMR_Engnr]

Well, I'm trying to get back into diagnosing and fixing this thing. The passenger side injectors are the ones that leak the most, and the fuel heater o-ring was leaking before I switched to the new style, and the fuel restriction switch was leaking, so I am thinking there might be a restriction on that side. What I am thinking is that I could disconnect the crossover hose between the two sides, pinch it off with some vise grips, and then run some hose from the last injector to a diesel fuel can. Theoretically this would mean that the fuel filter return and all passenger side injectors would be running to the fuel can and should have no restrictions, so if a restriction is the problem I should see all those leaks go away. Does that sound crazy?

I would think it is just the kit but since so many items on the filter head are leaking that's why I was thinking a restriciton. If the leaks persist, I might try the o-rings that came with the kit instead of the mcmaster viton (size 111) o-rings. I heard that the viton might be too hard and comparing them with the kit o-rings they look slightly different.

If neither of those work, I guess I'm down to just doing a complete overhaul with new injectors, a known good quality return kit, and hope that that fixes everything. I'd hate to do that and have it start leaking again because the problem was at the tee between the banks.

Another question, what is the purpose of the fuel filter leak off? I just found out that it is supposed to have a check valve fitting, so I guess it leaks off excess fuel from the difference between what the pump lifts and what the IP consumes? The IP also has a leak off so why not have the excess get leaked off by the IP instead of the in both places?

 

[UMR_Engnr]

So I disconnected the passenger side and ran it into a fuel canister. One injector cap was leaking as well as the fuel restriction sensor. So I reconnected the crossover line to the rear most passenger side injector. The previous injector was still leaking as well as the fuel restriction sensor and now the injector that I connected the crossover hose back to was leaking. I connected a fuel pressure gauge into the return line and it was reading less than 1 psi, so I guess there is no restriction. I'm going to try the o-rings that came with the kit and if that doesn't work then I'm just going to get a new quality kit and start over. For the fuel restriction sensor I'll plug it as a quick workaround.

 

[fordf350man]

i had an issue before when i put a new return line kit on, dont remember what brand the kit was but it was fine and the next day is started pooring out fuel also, i found the o rings were disintegrating from the diesel fuel, they werent compatiable dont know why they werent they came with the kit, i had to get o rings that were made for diesel fuel to stop the leak , but since i did that i havent had a problem