Urgent Help.

[Adam Hicklin]

After solving my battery problem I started the coach and found a fuel leak.  I’m pretty sure it’s the engine return fuel line.  I replaced the accessible part of that line a few years ago. Now it seems to be leaking from the rail of no return where all the lines run back to the engine.  I ran both the aqua hot and the generator with no leaks. 

Question: Where on the engine does the return line originate?  Question 2: I’m guessing he fix is to run a new line an alternative route, like every other line I’ve had to replace front to back.  Question 3:  is it just 1/2 inch fuel line?

Thanks.  Of course I’m supposed to leave tomorrow.  There may be a 1998 Marquis for sale soon. 

[Eric Maclean]

Adam
On a C12 the fuel return line from the back of the cylinder head runs over to the fuel filter housing where there is a built in fuel pressure regulator which controls the fuel rail pressure and dumps the return fuel back to the tank via line connected to the back side of the secondary fuel filter housing.this hose should be evident as is heads forward along the the frame rails towards the fuel tank.

Hope this helps
Eric

[Steve Huber Co-Admin]

Adam,
Location of fuel return line from pressure regulator on a C12.
Steve

[Adam Hicklin]

Thanks.  I found it through some trial and error.  It’s hard to see from the picture Steve posted.  I will try to post a picture tomorrow but I followed the fuel lines up and around and over and down and came to device which I’m Assuming is the pressure regulator.  A pressure line ran from the secondary filter to the device which was on the passenger side, toward the front of the coach to the side of the front cylinder head.  There was the pressure line going in and a regular fuel line with a hose clamp coming out.  This line went forward and disappeared in the frame rail. It looked the same size and vintage as the one going in to the tank at the front.  I cut it, and disconnected it at the tank, then blew compressed air through it.  It was the same line.  Tomorrow I will pick up some new line and reroute it front to back.  I hope that was the problem.  I can’t think of anything else that would be leaking from that area with the coach running.  I hope I’m right.  Thanks for the help.  I’ll let you know if it worked or not. 

[Eric Maclean]

Adam
Where was the return line in your coach leaking was it a hydraulic type line or just neoprene rubber and is it deteriorated or did something rub through it.

Eric

[Eric Maclean]

Adam
This is a link to a picture of a C12 the line that is disconnect from the rear of the filter housing is the return line.
https://www.google.com/search?sxsrf=ALeKk0247VqXNtknh52rXRCf3F5dq1VXyA:1622144788667&source=univ&tbm=isch&q=Cat+c12+fuel+system&client=tablet-android-lenovo-rev2&fir=1nmt-a9Pm99OEM%252CZAtAI3YSNKFnmM%252C_%253B3UQ3GMSGMgkd0M%252C-daRprTtJ9j6RM%252C_%253BdRHJyJtOomGE9M%252Co0RekMkeenpPsM%252C_%253BIb8Ujd74P0DViM%252C-daRprTtJ9j6RM%252C_%253BVQXbYBE1lVYLBM%252CNqZordXsOsiwLM%252C_%253Bv5dUPvM0XRBEjM%252C-daRprTtJ9j6RM%252C_%253B242usE55hfm_vM%252CcAdIdo83R27xKM%252C_%253B9U8DBzMo6xIvcM%252C-daRprTtJ9j6RM%252C_%253BL4b9zQEENs3kgM%252CgdOyld24AXDujM%252C_%253BbdkWxQ7vGattWM%252CewmUpfnzOgktVM%252C_%253BHH5bTcMJ-S18FM%252CKTqY0dKarOHOkM%252C_%253BAlIlo690sAU5gM%252Cp7DOQUis4pXCyM%252C_%253B1cSvFq179OYiTM%252C8Wnk0ukze4iGAM%252C_%253B66ihBZbw3icDeM%252CAX1klydkAwNAjM%252C_&usg=AI4_-kShb4E8Jj00K7L-Pb-LVEpwpLbffQ&sa=X&ved=2ahUKEwik5puf0OrwAhWIZM0KHU93DxgQ7Al6BAgFEEg&biw=1103&bih=690#imgrc=o_Qu-5r4P8MpNM
Hope this helps
Eric

[Adam Hicklin]

Eric, it was the rubber return line and it was leaking within the frame rail up front by the fuel tank.  My gUess is deterioration.  I had to replaced a small section a couple years ago, that I was able to access at the fuel tank.  On the engine end, the piece I removed was pretty cracked, but not leaking.  I ended up running a new line, back to front, through an alternative route, abandoning the original buried line, like I did the main suction line last year.   

I have yet to see a picture of an engIne set up like mine, and I forgot to take pictures before I closed everything up.  Had to get on the road. 

So now I’ve replaced the min suction line and the return line.  I’m sure the generator and Aquahot lines will start leaking soon.  Those are much harder to do, as they attach to the top of the tank, as I understand.

Thanks for your help! 

[Eric Maclean]

Apparently your tank configuration is different than mine as my fuel lines all go to the top of the tank and my main fuel lines are braided hydraulic lines.
 the Aquahot and diesel gen set on the other hand are 1/4 inch rubber lines and I've had to replace those.

When your under there the next time you might want to check the power steering lines on my coach the high pressure line wore through on the front edge of the passengers side frame rail at the front where it comes across behind the gen set and turns into the frame rail running the full length of the coach it was not fun to replaced as it's 40 feet long and runs through no man's land over the tanks and rear differential  it must be about the same for the fuel lines . luckily l haven't had to do the main fuel lines YET.

Glad you got up and running again hope the rest of your trip is trouble free
Eric

[Adam Hicklin]

Eric, my fuel lines, both the main (hydraulic line used) and the return (3/8 rubber fuel line) attach at the front of the tank.  Thankfully not on the top of the tank. I replaced the main line last year and I kick myself for not running a return line at he same time.  Just had tunnel vision at the time.  And you’re right, it wasn’t fun running a stiff hydraulic line 40 feet in limited space and awkward positions.  I ended up running the return line the same route so once I identified it, it only took about an hour.  I’m sure both the generator and aquahot feed off the top of the tank though.  Not looking forward to replacing those, which I’m sure will be sooner rather than later.  There is always something to do on these beasts.  It’s a love hate relationship!  Thanks for your help. 

[Steve Huber Co-Admin]

Adam,
On most coaches the generator fuel line exists the side of tank side  about 1/4 up from the bottom. This automatically shuts the geni down when your fuel level reaches 25%.
Steve

[Fred Brooks]

   Steve......?

[Steve Huber Co-Admin]

Fred,
See http://beaveramb.org/forum/index.php/topic,9776.0.html
I may have misinterpreted Gerald's statement by confusing "pick-up" with tank exit. 
Steve