Diesel leak above transmission?
 

Hey bombers- I'm a newbie to the diesel scene and to the forum so be nice!

My 06 5.9 has been leaving puddles in the drive way- thought it was from ac but when I crawled under and smelt it - yup it's diesel :td: I had read maybe it was from my fuel filter drain or seal- that's all dry- after drying everything I traced it up to the top of the transmission. There is a drip coming from between the engine and transmission and it slides its way down to the bottom of the tranny. This is only when running- Can anyone tell me what line this is? I can't seem to find any info! :argh: the hose is rubber and goes from rectangular box with fins back over toward passenger side. What is the name of the box also? The arrow for #11 goes over the rectangle I'm talking about. It is that top left hose that turns back behind motor- Truck is running and starts fine- no sense in wasting diesel unless it's in a black cloud! :tu: Thanks in advance

It's the fuel return line on the back of the head. 18mm wrench should work I think?!
It's a banjo fitting hopefully the line isn't cracked!

Thanks dangerous :tu: - do you think it's just loose and may need to be tightened up? I'm not familiar with the banjo fittings- I can't see exactly where it's leaking due to it being blocked by other lines and obstacles - when I reached in behind there I felt the line go from rubber to metal- do I need to worry about over tightening?

Before you dig into the fuel gallery return check all your lines looking for cracks or leaks, specififcally #4. Those lines will leak and the fuel will run off the back of the head making you think the issues is there.

A boroscope makes a wonderful tool to get into those tight places and find the source.

I have heard that #4 is notorious for leaking- I'll take a closer look tomorrow and try to get a visual on the leak- I found this other thread that might be helpful

https://www.dieselbombers.com/24-val...line-leak.html

Does the #4 line run from the drivers side top of the motor to the fuel filter? I noticed it's not bone dry on top of motor which makes me wonder if maybe there is a leak up there- However I would think I could see it seeping or spraying while running being- right there

If I can't figure it out tomorrow then off to the dealer :td:

#4 injector line is notorious fro breaking and really making a mess. All of the injector lines can suffer a crack at the cross over tube connection and it will be a small leak that will run off the back of the engine. If you have fuel on the top of the engine back of the intake horn you likely have a leak somethwere there.

Cerberus60 you were right- bad news for me- line #1,4, and 5 all are leaking where they enter the top of the motor at the flare- all the run off was dripping down back of the motor- dealer wants $871+ tax to replace 3lines and the retainers- aren't these line fairly easy to replace? Just 2 19mm fittings one at each end of the line? anything to be careful of when replacing them?

The lines are $40-60 at normal prices. Check with a local Cummins dealer or Genos Garage for prices. Dealer will be way expensive.

The lines are easy to replace. You NEED a backup wrench on the cross over tube so you don't disturb it and cause further issues. I think on the 06+ trucks just remove the valve cover and the gasket with the injector harness in it and you should be ables to access the cross over tube holder easily with a wrench.

The 03-05 trucks require removal of the VC spacer as the harness connector sits right over #5 cross over tube.

Phew
 

Okay - now that I have picked my jaw up off the ground- I called my local Cummins dealer(North San Antonio) they had 2 of my 3 lines in stock- prices were from $22-$28each- so for under $90 out the door I have all 3 lines- vs the dealer wanting $80-$127- ridiculous!

Putting in line 4&5 after I get my truck from dealer (doing tie rod ends on recall)

Found this video on how fuel travels throughout the system and also mentions the crossover back up wrench you were talking about. I Hope someone else can find it useful


Does anyone know torque specs on high pressure fuel lines? I have seen 41-44ft lbs- does that sound right?