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Topic: Fuel leak (Read 760 times) previous topic - next topic

Fuel leak

Yesterday, while installing a valve to make winterizing easier, I smelled diesel fuel. There was a puddle forming on the driveway, just in front of the fuel tank in the middle of the vehicle. It was actively dripping. I fired up the motor and generator, raised the vehicle, placed my square tubing supports, then shut the motor down. The dripping stopped, so I decided to wait until this morning to investigate.

I had a similar leak this summer after a fill up and thought the tank may have been overfilled and the heat of the day expanded the fuel.

The tank is less than 1/2 full now, so my prior theory is shot.

When I crawled under to survey the situation I found 3 fuel hoses with open ends in the area. 1 is very short and appears to be the culprit, one of the other longer hoses has fuel covering it that looks like run off from the short hose.

Can someone let me know the purpose of these hoses and my best bet to prevent future fuel leaks?

1997 U270 36'
Build #5115
2014 Jeep Rubicon towed
1972 Boston Whaler 16'
Charlie

Re: Fuel leak

Reply #1 –
(Probably) useless armchair comments, based on zero actual knowledge of your coach or situation:

I doubt the factory left any fuel hoses hanging down with open ends, so most likely happened post production.

Are those red lines in the photos newer replacement fuel hoses?  If so, you might want to search "red Gates fuel hose" on Forum.

Could be left overs from a prior owner's fuel hose replacement project, but why would the "old" hoses still have fuel in them?

If both your big engine and the generator still run, the hoses obviously don't supply them.

If cut hose is a "return" line from your big engine injection pump, fuel would be pouring out when engine is running.

If the hoses are attached to some kind of fuel tank vent, why would they drip with the tank half empty?

The cut on the end of the one hose looks clean and fairly recent, like it was done on purpose, rather than caused by accident.

Sabotage?  Did you recently irritate any of your neighbors?

Sorry, that's all I got.

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Fuel leak

Reply #2 –
The open ended hose might be the fuel tank vent. That's where mine exits. I had a pesky leak on our 95. Every once in awhile the fuel compartment would be wet. Most times it would not be. I never did find that damn leak and discounted the sales price $500 so the next guy could give it a try. Good luck.
jor
93 225
95 300
97 270
99 320

Re: Fuel leak

Reply #3 –
Fuel tank vent
Chris and Tammy White  CDA Idaho
Previous owners 1997 U295 36' 3126 Cat 300 HP Build # 4998
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Fuel leak

Reply #4 –
In the 3rd pic there is another line that is visible on the bulkhead.
Is it bolted to  the bulkhead with a clamp?
The reaswon I ask is Foretravel didn't generally use Aeroquip 2556-6 hose on the fuel tank vent line.
Re crank your generator and see if the leak starts while the generator is running. If so it is the return line off the generator.
I have never seen a hose come apart like it has been cut on its own so it could have been cut.
Also in the 3rd pic it apears that the hose in question is split. Is this correct as to what I see or is that daark spot a shadow?
I guess what I am asking is could the 2 ends we see have been connected together and be the gen fuel return?

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Fuel leak

Reply #5 –
Mike, actually the hose in question is the one that is cut off at the tip of the arrow. It appears to be spilling fuel onto the the longer, loose hose. The fuel is running down that hose. The majority of fuel is landing on the frame cross member. The "cut" is just a reflection.

The coach has been sitting for 3 weeks without running the generator or motor. I just happened to be working in the water pump bay when is smelled diesel and found the fuel leaking onto the ground.
I then started the motor and generator. Both started easily, ran well and the leak stopped.

Here are some additional pictures:
1997 U270 36'
Build #5115
2014 Jeep Rubicon towed
1972 Boston Whaler 16'
Charlie

Re: Fuel leak

Reply #6 –
Ok in pic. 1 the tank vent line is the one to the left that is in the clamp that is attached to the angle iron.
Now to figure out what the other line is from.
It sure seems like it is either fuel to or return from the generator as nothing else up front uses diesel fuel.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Fuel leak

Reply #7 –
The short line that appears to be the source of the leak runs toward the back of the coach, at least the short length I can see.
 I can't figure out how it could be leaking from a half full tank and the motor isn't running!

Often when something isn't working, I check it for my fingerprints and find I'm the culprit!!! Not the case this time!
1997 U270 36'
Build #5115
2014 Jeep Rubicon towed
1972 Boston Whaler 16'
Charlie

Re: Fuel leak

Reply #8 –
Here is a possibility that I have seen happen on rare occasions.
If the vent line has been stopped up with a mud/dirt dauber  then with a weather change the fuel can be pushed out an open hose due to barometric pressure change. With your coach being a '97 both the generator suction and return taps should have the same length pick up pipes. The reason  Foretravel did this was so no matter which way someone hooked up the generator fuel lines while the coach was on the line it would be correct. Some of the older model coaches had one long pick up stand pipe and a short return stand pipe.

How long did you let your generator run? You should have an 8kw so it's fuel flow/use will be small.  If you didn't let it run for 10 or 15 min. you need to. If this is the suction hose you may not have let it run long enough to use all the fuel out of the hose.

 If this hose does go to the generator return side you need to check it to see if it is plugged up also. The generator can run a while with the return line stopped up.

Remember this is just a WAG and some random thoughts.
Our coaches are less than 50 apart.
Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Fuel leak

Reply #9 –
Mike, the leak started again!
It is raining hard, so climbing under the coach was not fun!!!
I verified that the leak was through the short line that I suspected.
I pulled some more of it out and pushed it up to stop the leak.
Tomorrow I'll remove the cover from the driver's side of the fuel tank to see if I can trace the line.

I thank you for your feedback and will update you on the results.
1997 U270 36'
Build #5115
2014 Jeep Rubicon towed
1972 Boston Whaler 16'
Charlie

Re: Fuel leak

Reply #10 –
Go out and loosen one of the fuel fill caps to see it that helps overnight. Don't take it completely off just loosen it up a little.

That line must go to one of  the center taps on the fuel tank.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Fuel leak

Reply #11 –
When this happens, remove the diesel tank fill cap.  Any pressure???
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Fuel leak

Reply #12 –
Yes, there was pressure!
1997 U270 36'
Build #5115
2014 Jeep Rubicon towed
1972 Boston Whaler 16'
Charlie

Re: Fuel leak

Reply #13 –
That leads me to think the vent line is stopped up causing the fuel to be pushed out the open line.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Fuel leak

Reply #14 –
I agree with your assessment.
Tomorrow I'll locate the vent line, clear it and hope the problem. is resolved,

Thank you Mike and Bret.
1997 U270 36'
Build #5115
2014 Jeep Rubicon towed
1972 Boston Whaler 16'
Charlie

Re: Fuel leak

Reply #15 –
You will need a 1/2" wrench or socket to remove the hold down bolt that holds the vent clamp bracket secure.
Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."