Diesel Leak?

[dreamchasers]

This one is a puzzler? The Webasto heater I recently rebuilt seems to work fine, with no leaks in the heater compartment. I tested the unit for several days and all was well. I noticed yesterday that a puddle of diesel (2-3 gallons) had accumulated under the coach. Farther testing indicated that diesel only accumulates while the webasto is running. The leak seems to be in the area forward of the differential and upwards. My coach has an air conditioning condenser mounted in this area, so it is very congested and hard to reach this area from a creeper. So this morning I raised the coach using the air suspension, started the Webasto and slid under expecting to see a leak. To my surprise, no leak! So I ran the unit all day long sliding under the coach every hour to check for the elusive diesel leak.

This evening, I decided to let the Webasto run overnight for additional testing. So I lowered the coach, dumped the air from the suspension, locked up the coach and took one last look under the rig as I was heading indoors. It was leaking! The leak seems to be in the area forward of the differential and upwards. My coach has an air conditioning condenser mounted in this area, so it is very congested and hard to reach this area from a creeper (Where is that drive over pit when you need it). When the coach is lowered, it is impossible to slid under with a creeper, so I will have to duplicate the conditions for the leak, then raise the coach and slid under to see if I can locate the fault.

With my limited knowledge of the Prevost systems, it appears the leak is in the diesel return line from the Webasto to the diesel tank. The Webasto documentation states that excess fuel in bypassed to the return line as part to normal pressure control for the nozzle chamber. My question for the experts: 'is the return line a single rubber line from the Webasto to the diesel tank or is their other components I should be looking for that could be potential leaks.'

Any ideas are appreciated.

Hector

[JIM CHALOUPKA]

Hector, now that you know the approximate area of the leak, it would be best to clean the suspected area as well as possible. That makes for ease in pinpointing any leak. Use a very bright light (rechargeable spot light 1 million CP works well) to look for the leak. Check for loose fittings, or clamps and deteriorated or damaged tubing or hose.

To not see the leak and then find 2 to 3 gal. on the ground is puzzling. I suppose the fuel could be accumulating in some area and then dumping, but I don't think so. Place a clean piece of cardboard on the floor in the suspected area and try to see where the first drips appear and go straight up from there.

If you go back under the bus be sure to block it up for safety. Also wear safety glasses and beware of high pressure diesel leaks that can penetrate the skin. ( you don't know yet what is leaking). Oil injected into the flesh should be treated in a hospital emergency room, pronto!

This is all just general info. and maybe someone will know exactly what is going on for you.

You ask about a rubber return line. My only comment on that is in home heating (with oil) rubber lines of any kind are not allowed in any part of the system.

Yea and about the PIT, Denny told me that when you finally get the pit you won't need it let alone want it:eek:

[MangoMike]

Hector,

The return line is direct for the Webasto.

Could this be a generator issue? It also has a return line to the tank.

Jim has some good points about getting the area clean and using the cardboard.

2 or 3 gallons is a lot of diesel.

Mike

[dreamchasers]

I will be using the coach for the next few days and will be looking for a pit to back over the pit and look for the diesel leak. Crawling around under the coach on a creeper leaves much to be desired.

While I was at Prevost in Fort Worth a few weeks back, the technician replaced a hydraulic hose that they stated to be leaking. While replacing the hose from the hydraulic fluid tank to the 'bulkhead, many clamps were removed in order to remove and replace the hydraulic hose. When they reinstalled the hose, they ty-rapped the replacement hose to others forming a bundle of hoses, instead of the hose clamped flat to the under flooring. I am wondering if when the coach is lowered, if the top of the differential is pinching this hose bundle and blocking the flow of return diesel from the webasto? Hume? At least it is a theory.

For those that have spent time under the coach when the suspension is deflated, how much room is their between the top of the differential to the under floor structure when the coach is lowered?

Hector

[Jon Wehrenberg]

Hector...When the bus sits down there are a few inches. It is not tight from the top of the pumpkin to the underside of the floor.

If you need a pit, on occasion when on the road I have gone to a truck stop and used their pit if it was unoccupied. If you buy fuel or ask them to grease the coach they really don't have a problem with that.

I am assuming when you talk about hydraulic lines you are meaning the power steering lines. If Prevost did the work, they stand behind their work so I would see how they want to handle the situation because if it was not a problem before they worked on it, something was done to create the problem and they need to either correct it, or authorize you to have it corrected on their dime.

[dreamchasers]

The follow up story is not one that those that take their coach to Prevost Service Centers will want to hear, but here is what happened.

I took my coach to Prevost Fort Worth the second week in November, 2007. The techs worked through a list of items, and after a week I was on my way home. As I drove out of the parking lot, I switched on the dash A/C and after having a new compressor installed, only ambient air temp would come from the vents. Oh well, the work was guaranteed.

Then while spending time at my business in Orange, Texas (2 weeks later), I stayed in the coach in the parking lot in the evenings and noticed a diesel leak under the coach, which prompted this thread. I stated that 2-3 gallons of diesel had leaked, but in reality, more than the stated amount had leaked (Any EPA guys listening? I noticed that the leak only occurred when the Wabasto was running and the coach was setting low.

When the leak was inspected by Prevost, it was found that the technician that preformed the work had cut the clamps attached to the undercarriage holding my hoses above the rear end pumpkin and grouped them together with tie raps when he replaced a low side power steering hose. The hose was replaced because the tech thought the small leak I had at the rear of the coach was coming from the power steering return hose (The power steering hose was not the leaking offender, but a leaking diesel check valve(See picture.)

When the coach would sit low, the welded A frame attached to the rear axle, would extend into the bundle of hoses and crush the hoses. The Wabasto return line, high pressure return line, would become pinched and the hose ruptured. See picture.

As you can imagine, I was disappointed with the work performed on this item. I had Prevost replace the damaged line and re install all the clamps that were cut.

http://dreamchasers.us/pog/IMG_2908.JPG
This is a check valve in the engine return line. It prevents the diesel tank from siphoning out when and if fuel lines are disconnected at the engine injection pump. A small crack in the aluminum housing was causing a very small persistent leak. The replacement check valve in made of brass.


http://dreamchasers.us/pog/IMG_2850.JPG
See the hoses that are ty-raped that are pinched when the suspension is de-pressures.

http://dreamchasers.us/pog/IMG_2852.JPG
Here you can see the damage.


http://dreamchasers.us/pog/IMG_2872.JPG
This is the Wabasto fuel return line. If this line is pinched, the fuel line can reach pressures as high as the Wabasto fuel pump (140 PSI).
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[dalej]

Good story Hector! You are really starting to understand your coach. It takes on a whole new meaning when you get the bus up on stands and start looking around.

[Darl-Wilson]

Hector, where are the pictures? Also, where are the battery pictures located on your website. I would be interested in seeing both. You can private email them to me if you are unable to post on the forum. I think the forum has a size limitation. Thanks & you folks have a nice personal website!

[dreamchasers]

Hector, where are the pictures? Also, where are the battery pictures located on your website. I would be interested in seeing both. You can private email them to me if you are unable to post on the forum. I think the forum has a size limitation. Thanks & you folks have a nice personal website!


I am having problems with the forum picture posting process, so I posted the pictures on my web site and linked to the photos. The pictures are showing for me. If you are having problems, try reloading the page.

Is anyone else having problems with not seeing the linked photos. Maybe, the larger photos is not such a good idea?

Hector

[JIM CHALOUPKA]

The pictures and the post is fine.

[Darl-Wilson]

Hector, my default browser is Firefox but since I couldn't see the pictures I tried IE and had the same problem. I used the link you have in your post that shows your previous MH. If you have time simply email them to me a darl@nvhf.com

Thanks

[garyde]

The photos can be a max of 600 x 600 pixcels I beieve.