The Good, the Bad the Webasto ....

[Ray Davis]

Ken Zittrer (Bluevost) and I spent about 5 hours today trying to solve a Webasto problem that has us both stumped. I'm looking for help from the collective brain trust!

A couple of weeks ago I noticed a diesel leak back near the right side of the engine compartment. I put a drip pan under the bus as I didn't have time to deal with it. Yesterday when I went to the bus, there had to be at least a quart, perhaps a half gallon of diesel in the pan. OK, it's time to do something.

It's defininately the Webasto which is leaking, but Ken and I tried everything we could think of, but it's still leaking. Here's the pertinent (and perhaps not so pertinent) details, which will helpfully lead us in the right direction.

1. fuel leak seems to be in the incoming fuel line.
2. fuel comes in through a fuel filter (which doesn't appear to have any "filter element" inside).
3. It connects into the port labled "S".
4. There is another port labled "R", which has a fuel line, which exits out the side of the unit and heads into the engine area. Not sure where. This line doesn't appear to be leaking, although it was wet.

5. We replaced the incoming fuel line (from fuel filter forward), and also replaced the hose clamp. Still no luck.

6. It was noticed that when we opened the unit, that the square grommit which it used around the fuel inlets was crushed in some previous repair attempt (previous owner).

7. We did our best to fix up the crushed gromit, adjusted the electrodes, and replaced unit.

8. Unit still leaks at an alarming rate (5-10 drips per minute, worse when unit is fired up).

9. When unit fires up, it runs, but blows a LOT of white smoke, but otherwise seems fully functional.

We're hoping something above will be a clue to someone. The fuel line was 1/4 inch standard fuel line. We have no clue where the other line goes to/from. It's not clear whether it's another fuel in, or not?

We spent nearly 5 hours on this, having the unit apart 4 times. Everything is tightened as best we could, but almost immediately after buttoning up, it's dripping. If we fire it up, it starts dripping profusely.

Any suggestions would be most appreciated.

Thanks,
Ray

[Jon Wehrenberg]

I believe S is the supply, and R is the return. Fuel not used by the Webasto returns to the fuel tank.

Is there any way to photo the specific area where it is leaking?

Also, has the unit been cleaned 100% so the origin of the leak, not where first visible to you now, is evident.

If you need to, disconnect the fuel supply and return lines and plug them while you do what is necessary to make sure there is zero fuel, dirt, wet areas etc. Tracing a leak is impossible unless you can verify the source which may be some distance away from where you think it is.

[garyde]

Hi Ray. I would disconnect both lines and cap with a screw or bolt. If leak has stopped, reconnect one line and check again, if no leak , connect the other line. If it begins to leak, that line is leaking or your port is damaged.

[Ray Davis]

We are sure it's the supply line that is leaking. What's not clear is whether or not it's leaking from the hose itself (getting by the clamp), or it's somehow leaking further up the inlet nipple, and dripping back down onto the hose.

We can't tell that when the burner unit is removed from the combustion chamber. There was evidence of some fuel inside the burner unit, down where the S and R lines enter.

Once cleaned, and simply "sitting", it drips slowly. It's after the unit is turned on that it really begins to go.

Visually it looks like fuel is just getting around the hose clamp on the S side. But, we've cranked that down like crazy, replaced the hose and clamp. I'm wondering if that inlet has perhaps been damaged, and won't allow a seal?

Ray

PS: is the ton of white smoke somehow related to this problem? Does that indicate too much fuel?

[JIM CHALOUPKA]

We are sure it's the supply line that is leaking. What's not clear is whether or not it's leaking from the hose itself (getting by the clamp), or it's somehow leaking further up the inlet nipple, and dripping back down onto the hose.

We can't tell that when the burner unit is removed from the combustion chamber. There was evidence of some fuel inside the burner unit, down where the S and R lines enter.

Once cleaned, and simply "sitting", it drips slowly. It's after the unit is turned on that it really begins to go.

Visually it looks like fuel is just getting around the hose clamp on the S side. But, we've cranked that down like crazy, replaced the hose and clamp. I'm wondering if that inlet has perhaps been damaged, and won't allow a seal?

Ray

PS: is the ton of white smoke somehow related to this problem? Does that indicate too much fuel?

Ray, you indicate that it continues to leak in the same area, even after using a new hose clamp and hose. That indicates to me that it might be the fitting at that connection! Cracked, or loose in the pump.

IMHO clamps and hose are mickey mouse (no offense to Walt & Co.)when dealing with diesel. Have some Parker lines made up at your favorite auto store (NAPA) and install the appropriate fitting at the pump and fuel source!
It is also possible that the pump housing has a crack or defective casting (pinhole), that sprays onto the hose and makes you think the hose is the problem. I find that a good tool to trace diesel leaks is white Kleenex. The most minute amount of fuel shows up. Work from one end to the other using fresh as needed until you locate the leak. Wear the blue Nitrile gloves to keep the diesel off your skin (toxic and it burns ) when performing these tasks where repeated soakings are inevitable.

Hope this helps JIM

[JIM CHALOUPKA]

Ray, I think the white smoke is due to a clogged/dirty nozzle. It could also be due to excess fuel in the combustion chamber. If the smoke situation does not go away after several minutes of running, replace the nozzle and test.

[Larry W]

I had a fuel leak on a aqua hot (Understand they are the same pump unit) on the Monaco plastic we had. I found the seal on the pump shaft had failed. A few drips while turned off and a LARGE leak while running.

[Jon Wehrenberg]

Ray, After the leak is cleaned and dry use your fingers to find the source or a mirror or any other means to spot the origin before it gets to the point that it will start dripping. Dripping means that it may have run downhill before it finally lets go. You obviously need to identify the first place it emerges.

I don't know how it has been set up, so any advice may only appear applicable to a Liberty, but if I had the difficulty seeing the source you describe, I would remove the fuel lines where they are NOT leaking, leaving them attached to the head, and then remove the head so you can look at it closely. Set it in a position approximately like that of when it is installed and using a pump oil can with diesel fuel in it pump fuel into the supply line and look for the source.

The Webasto is about the only thing on your coach that offers the luxury of easily removing it for a close up and personal look for leaks and repairs. Take advantage of that and consider yourself lucky it wasn't a similar problem on the engine or generator that you cannot disassemble easily.

[dreamchasers]

Ray,

I recently overhauled my Webasto because of leaks generated inside the Webasto housing. My leak was very simular to what you are describing, were the diesel would drip down the inlet hose to the heater. After re securing all connections, cleaning the diesel drip area, I determined the leak was coming from inside the head. In my case, the leak was being generated from the diesel pump seal. When disassembling the head, it became clear where the leak was occurring, you could see a 'drip trail' leading to pump seal.

I order a new pump, (which comes with a new .35 nozzle) and an assortment of new gaskets. After replacing pump and installing the assorted orings and gaskets, the unit was leak free. I ordered all the parts from Prevost at for approximately $380, which included overnight shipping from two locations (Nashville and New Jersey) to my home in Texas.

It was frustrating identifying the leak, because I had to remove and disassemble the head. I used the Webasto manual, available on line, and Mango Mike's tutorial on Webasto repair.

It worked for me.

Good luck!

Hector

[dreamchasers]

Here is the link for the Webasto repair manual, if needed. The pdf file is 9.5 Meg, so be patient if you do not have broadband.

Sorry for the double post, I had to sort out how to post a url.

http://www.techwebasto.com/heater_main/699745.pdf

Hector