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1994 6.5 turbo diesel has fuel running out of the hole in the inspection cover

Whiplash123

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Please help ! I have only owned Chevy Trucks but this is my first diesel and I'm lost
I can't see fuel leaking anywhere on top of rear of the engine but its running
Out of the inspection cover
 

Will L.

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First, welcome. Dont sweat it, tons of guys here that know these engines amazingly well. We can walk you through any issue.
Stick around after this problem is solved to learn from our mistakes, and know that most diesel shops do not understand this engine and will do things the way newer diesels are designed and that will cost you big money to learn their mistakes.

Originally On top of the engine is a plastic cover that says hides the middle of the engine. Get that out there- most never reinstall it.
in the rear center of the engine you will find the FFM (fuel filter manager) it has a cartridge fuel filter, in it and a few fuel hoses going through it. Take a look if fuel is leaking from it, or the hoses coming off of it.
Fuel leak obviously danger for fire, but also can keep the engine from running properly. Something different about diesels is if a hoseclamp or something is loose and that line has suction rather than pressure, it can suck in air and not let the engine run right even if it isn’t dripping fuel. So consider the easier to fund fuel leak a good thing because they are easier to find

A recently replaced fuel filter is a common source of fuel leaking when the large nut on top didn’t get screwed in staight.

There is a valve by the thermostat for draining out water from the fuel filter that could be slightly open. Follow the hose from FFM to it and check valve closed fully and hose condition to it.

If you get to replacing fuel line because you find defective hose- a couple things to consider.
Only buy sae30r9 hose to handle the modern fuel. The old hose doesn’t stand up long term to the new fuel - so deteriorating hose could be your issue.
It is 3/8 line feeding to the ffm, and 5/16 line coming out going to the drain and another 5/16 line coming out going to the ip (injection pump). -however many people upgrade that ip line to a 3/8 for better flow helping with longer parts life & drive ability.
then there is a 1/4” line that comes out the ip to return to tank. There are 1/8” lines on each injector thatconnect to each other then to the same return line as the ip return. If the 1/8 lines leak, they usually leak down the side of the engine. If the 1/4” part is leaking, or any of the 5/16 line, the ffm, or it’s connections - They leak into the center of the engine which has a valley. The fuel goes to the back of the valley where a hole is drilled that lets it leak down onto the flywheel and clutch or flexplate and torque converter if auto trans. Then it gets to the flywheel inspection cover on the bottom and comes out that hole.

Take pictures and post here by using the button below this box when typing that says “attach files” and choose “full image”. Or a video to YouTube, bitchute, etc and post the link here for us to watch. Ask tons of questions- we all had to start learning some where.

Depending where you live- a few guys here can meet up to help. I am in the Las Vegas Nv area.
 

Jaryd

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Look in the engine valley with a flashlight for fuel puddled there. At the back right hand side of the valley is the valley drain hole and a lot of these engines have a tube that goes down and makes whatever is leaking in the valley come out of the inspection cover like what your seeing.

Since you know it’s diesel fuel that you are seeing. I would bet that the fuel filter housing or the lines connecting to it is leaking. If it’s the filter housing leaking it’s not a hard job or expensive to reseal. Leroy Diesel is a site vendor and sells good stuff for these rigs. https://leroydiesel.com/products/fuel-filter-manager-oring-set/

You could raise the filter housing up for better access and checking for leaks using 10 x 1.5 mm all thread rod.
 
Last edited:

Stoney

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Welcome to TTS. Looks like the guys already have you covered..
Side note I just learned something from this thread. Thanks to @Will L . Didn't know about the fuel hose issue, was considering changing all my fuel lines going from tank to lift pump to engine and back cause there in poor condition...(metal ones are rusted pretty bad) gonna replace with rubber. Now I know which type to get.
 

Whiplash123

New Member
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First, welcome. Dont sweat it, tons of guys here that know these engines amazingly well. We can walk you through any issue.
Stick around after this problem is solved to learn from our mistakes, and know that most diesel shops do not understand this engine and will do things the way newer diesels are designed and that will cost you big money to learn their mistakes.

Originally On top of the engine is a plastic cover that says hides the middle of the engine. Get that out there- most never reinstall it.
in the rear center of the engine you will find the FFM (fuel filter manager) it has a cartridge fuel filter, in it and a few fuel hoses going through it. Take a look if fuel is leaking from it, or the hoses coming off of it.
Fuel leak obviously danger for fire, but also can keep the engine from running properly. Something different about diesels is if a hoseclamp or something is loose and that line has suction rather than pressure, it can suck in air and not let the engine run right even if it isn’t dripping fuel. So consider the easier to fund fuel leak a good thing because they are easier to find

A recently replaced fuel filter is a common source of fuel leaking when the large nut on top didn’t get screwed in staight.

There is a valve by the thermostat for draining out water from the fuel filter that could be slightly open. Follow the hose from FFM to it and check valve closed fully and hose condition to it.

If you get to replacing fuel line because you find defective hose- a couple things to consider.
Only buy sae30r9 hose to handle the modern fuel. The old hose doesn’t stand up long term to the new fuel - so deteriorating hose could be your issue.
It is 3/8 line feeding to the ffm, and 5/16 line coming out going to the drain and another 5/16 line coming out going to the ip (injection pump). -however many people upgrade that ip line to a 3/8 for better flow helping with longer parts life & drive ability.
then there is a 1/4” line that comes out the ip to return to tank. There are 1/8” lines on each injector thatconnect to each other then to the same return line as the ip return. If the 1/8 lines leak, they usually leak down the side of the engine. If the 1/4” part is leaking, or any of the 5/16 line, the ffm, or it’s connections - They leak into the center of the engine which has a valley. The fuel goes to the back of the valley where a hole is drilled that lets it leak down onto the flywheel and clutch or flexplate and torque converter if auto trans. Then it gets to the flywheel inspection cover on the bottom and comes out that hole.

Take pictures and post here by using the button below this box when typing that says “attach files” and choose “full image”. Or a video to YouTube, bitchute, etc and post the link here for us to watch. Ask tons of questions- we all had to start learning some where.

Depending where you live- a few guys here can meet up to help. I am in the Las Vegas Nv area.
 

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Whiplash123

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Ok so I'm not sure if I did all that right !
I did find it leaking at the hose in back of filter housing I put new on and cut hose back
I checked the valve in front by thermostat housing it seemed good I've been checking all the little return lines etc and just still can't see the leak ! I did find a little critter nest under the top of intake and cleaned that out !
Then I asked you guys for help that's about all I figured out so far

I haven't even had a chance to touch it today but if the mosquitoes dont carry me away I plan on working on it yet tonight ! Thanks for any and all info !

Much appreciated !!!
 

Stoney

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This may sound dumb. But wouldn't it have to be a return line if it's a hose leak?? The lines going in would suck in air not blow out fuel Wouldn't they?
 

Will L.

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Pics posted ok, but not as full image- they posted as thumbnail. Unfortunately on iphones, when we click it- the pic only gets a little bigger and can not zoom in to see details well. So maybe one of the guys on a desktop can zoom in and look around to spot things.

I see what may be fuel around the ffm on the intake manifold y where it is mounted. That could indicate a leak in that area.

If you run a jumper wire to the lift pump, it can pressurize that line and help you find the leak.
 

emmott

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All lines downstream of the FFM and lift pump should be above atmospheric pressure if the lift pump is functioning
 
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