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View Full Version : Burned a hose like an idiot, help me figure out what it is


primeintellect
10-04-2018, 04:23 PM
2011 Freightliner Sprinter Bluetec

Just finished installing a diesel heater under the passenger van, and in my rush to test it out, ran it for maybe 3 minutes. Well, in that time, the exhaust pipe was resting on a hose right where it comes out, and managed to melt halfway through. I had already ordered exhaust wrap and heat shield, but it hadn't come in yet, and I figured I would be fine with a short run test but apparently was wrong. It's a small hose, maybe 3/8" inch and fairly rigid.

It appears to be going back about halfway down the van to a large black tank on the passenger side, I'm assuming that is the DEF tank or something? Does anyone have a wiring/hose/part layout of the underside of the van to help me figure out what hose this is, and how screwed I am? I'm hoping that I can just patch or replace the hose without too much trouble, and luckily it's up on a ramp in my driveway and doesn't need to be driven.

I've included a terrible picture of the hose in question, this is basically directly underneath the passenger seat, and is the smaller hose.

F2ca170
10-04-2018, 04:31 PM
This is just a wild guess..... but I would think the larger hose is the hose for filling the DEF tank, and would run from the fill location under the hood back to the tank. Therefore the smaller line would probably be a supply line for the DEF to used from the tank.

primeintellect
10-04-2018, 04:55 PM
That's what I was assuming as well. Am I correct in my assumption that the large black tank about halfway back on the passenger side is the DEF tank? If so, I'm hopeful that a patch and repair job for the hose won't be too big of an issue to do myself.

F2ca170
10-04-2018, 05:06 PM
That's where my DEF tank is. Long and rectangular and shallow at various points.

The DEF fluid crystallizes if exposed to air. You might make sure your patch is a rubber type compound like the hose is made of, and sealed tight. I have no idea if the DEF reacts with other types of adhesive or hoses is why I mention that.

Maybe someone else will chime that knows more about what repair is needed.

I would say replacing the hose is best overall.

Edit: Just thought of this.
Can you cut the hose and clean it up a bit, and put a hose coupling in it? That might work if you have some slack hose. Yet I have no idea if that might affect a sensor reading a correct pressure or something (if the coupling restricts the line too much).

primeintellect
10-04-2018, 05:18 PM
That hose has also been open for the day, as I noticed it last night late. You think I should drain the whole DEF tank and refill too? Would it by crystalizing if that hose was left open with a small 1cm hole in it for a day?

Unfortunately it seems like the 'hose' is fairly rigid, almost like a thick plastic, rather than a rubber type fuel hose.

F2ca170
10-04-2018, 05:45 PM
I personally wouldn't drain the tank. It won't hurt the DEF that bad letting a little more air get to it. The tank gets air in it anyway as the fluid is used up, so it's not that critical until you fix it I wouldn't think.

That's exactly why I believe all the people that say the tank should be kept topped off, and not to wait for the light to come on. That concept keeps as much air out of the tank as possible.

Bobnoxious
10-04-2018, 05:58 PM
I personally wouldn't drain the tank. It won't hurt the DEF that bad letting a little more air get to it. The tank gets air in it anyway as the fluid is used up, so it's not that critical until you fix it I wouldn't think.

That's exactly why I believe all the people that say the tank should be kept topped off, and not to wait for the light to come on. That concept keeps as much air out of the tank as possible.

IMHO, the logic behind keeping the DEF topped-off is to keep the DEF tank level sensors submerged to avoid activating low-level DEF warning or Start Count Down Message. Can't determine what line has been compromised. Emptying DEF tank may not be necessary. Patching is not a good idea. Take more pics using flash and tag damaged area with tape.

More info here: http://diysprinter.co.uk/reference/Sprinter-Tech-Overview-2000-2010.pdf

F2ca170
10-04-2018, 06:11 PM
I agree with what you are saying Bobnoxious.

In my mind that also would keep the sensor from getting crystallized over since it's staying submerged. In other words.... keeping everything WET, and keeping the most air out as possible. That way the tank and components have less chance to crystallize inside.

ptheland
10-04-2018, 06:38 PM
Yes - the large black tank tucked next to the side entry step is the DEF tank. In mine, the fill hose is good sized (maybe 1 1/2 inches on the outside diameter) and goes into the forward end of the tank near the bottom. I wonder if the smaller hose is a breather tube. It would take the air from the tank and bring it up to the filler neck under the hood. That would allow the DEF to flow fairly smoothly through the fill tube.

You might see if you can trace that cooked tube up to the fill neck area. I have a vague recollection of a small tube joining the filler just below the top of the filler under the hood. IF that is the case (a very big IF there), I don't see a problem with patching the tube. It would carry nothing other than air. If you go that route, I would try adding a bit of DEF to make sure the fill process still works smoothly, and that there are no leaks at your patch. Assuming everything looks ok after a small fill, AND if you have some idea of how much DEF it should take, I'd try filling it all the way and see if any issues arise. Better to check things thoroughly while your memory of the work done is fresh.

primeintellect
10-04-2018, 08:03 PM
IMHO, the logic behind keeping the DEF topped-off is to keep the DEF tank level sensors submerged to avoid activating low-level DEF warning or Start Count Down Message. Can't determine what line has been compromised. Emptying DEF tank may not be necessary. Patching is not a good idea. Take more pics using flash and tag damaged area with tape.

More info here: http://diysprinter.co.uk/reference/Sprinter-Tech-Overview-2000-2010.pdf

Thanks for this, I'm almost positive that the hose is this one that I've circled in red from the exhaust. I want to say it's the line between the DEF pump and the DEF dosing valve

Bobnoxious
10-04-2018, 08:26 PM
This might be used as a guideline to replace the line? Dunno.

https://sprinter-source.com/forum/attachment.php?attachmentid=27921&d=1289322191

F2ca170
10-04-2018, 10:21 PM
This might be used as a guideline to replace the line? Dunno.

https://sprinter-source.com/forum/attachment.php?attachmentid=27921&d=1289322191

Nice find!!

ptheland
10-05-2018, 12:20 AM
Thanks for this, I'm almost positive that the hose is this one that I've circled in red from the exhaust. I want to say it's the line between the DEF pump and the DEF dosing valve

If that is the case, please do not follow my earlier advice.

If it IS the line delivering DEF to the exhaust, I agree with Bob and would suggest replacement.

primeintellect
10-05-2018, 01:59 AM
If that is the case, please do not follow my earlier advice.

If it IS the line delivering DEF to the exhaust, I agree with Bob and would suggest replacement.

I'm almost positive that it is, I (mostly) traced the hose from the DEF tank to the dosing valve attached to the exhaust, which looks almost identical to the diagrams I saw, so thank you all for that.

I guess the question now is: how do I replace the hose? It's very rigid, it has what looks like a quickconnect style attachment, and 50% of it goes through a hole in the frame and dissapears to above the tank. The hole isn't large, it's a half oval that bites through about half the line, but definitely exposes the inside. Any reccomendations for how to either patch or replace it? Do I need to drop the whole DEF tank and order some replacement tube or do you think it can be patched? any idea on how much pressure that tube carries and how corrosive this stuff is? think that normal fuel hose repair would be sufficient for the tube?

Bobnoxious
10-05-2018, 02:18 AM
DEF is basically urine, so if you get it on your hands it's not going to burn but will corrode electrics. Pressure? 50 kP comes to mind. Patching, I think, is out of the question considering the consequences triggering no start countdown. Before you perform any work disconnect the battery near the accelerator pedal. Read warning label prior to disconnect. As far as replacing the line, I have zero hands on experience.

Bobnoxious
10-05-2018, 02:23 AM
What is 5 bar converted to psi? Siri says...

Aqua Puttana
10-05-2018, 01:37 PM
... think that normal fuel hose repair would be sufficient for the tube?
If this was a metal line it would be less complicated.

The plastic may not have enough structure to seal an external patch hose.

As a temporary repair until the proper parts can be sourced, it may be possible to use a proper sized insert inside the tubing to give structure for the hose to seal. In addition, because there are no barbs or bulb, the plastic tube ends will need to be stabilized or the internal pressure can eventually slip the hose off the smooth tubing.

The best choice would be to replace the parts as necessary.

:2cents: vic

primeintellect
10-09-2018, 10:33 PM
I've been having trouble actually identifying the part number for the hose/line in question. Does anyone know a part number to reference, or the best place to look for this part would be? I'm guessing O'reiley's or NAPA is probably not going to have something like that in stock. Maybe they could order it for me? Or is this a "get it towed to a dealer" type situation?

Bobnoxious
10-09-2018, 10:35 PM
I've been having trouble actually identifying the part number for the hose/line in question. Does anyone know a part number to reference, or the best place to look for this part would be? I'm guessing O'reiley's or NAPA is probably not going to have something like that in stock. Maybe they could order it for me? Or is this a "get it towed to a dealer" type situation?

I am thinking it's a dealer part.

F2ca170
10-09-2018, 10:47 PM
I just did some searching.... And it's not listed at any of the big parts dealers online (rockauto, O'Riley's and etc) and none list a DEF line at all for it (when searching model specific). I did find a 1" universal DEF dispensing line sold per foot at rockauto.... But that's really no help. So like Bob said.... More than likely a dealer item only. A MB parts department can find the correct line you need using your VIN number. So you can probably call around and price the line from several dealers.

Bobnoxious
10-09-2018, 11:49 PM
Maybe barbed hose splicer? Can you tease sufficient slack from the line to place a splicer of appropriate diameter?

primeintellect
10-11-2018, 05:26 AM
Hey thanks for everybody's help. I ended up removing the passenger stepwell cover and the plastic cupboard underneath to see even more, and after pouring over the diagrams, the burned hose was actually the breather hose for the fill hose for the DEF tank. Luckily that is probably the least important hose of all of them. I think I'm going to try to source a replacement or just patch it up. Should I drain and refill DEF if it's been exposed to the air like that? Thanks for the tips.

Bobnoxious
10-11-2018, 06:44 AM
I think you'll be okay. Keep an eye...both eyes on it for leaks.

Aqua Puttana
10-11-2018, 12:40 PM
I know what I would do, but I most often take the McGyver approach.

... I think I'm going to try to source a replacement or just patch it up.
If it is just a vent it can't leak liquid and will not be under any pressure to speak of. Find a hose or barb size that will be snug and patch it in.

...Should I drain and refill DEF if it's been exposed to the air like that? Thanks for the tips.
Don't overthink it. DEF is exposed to air during service isn't it?

:2cents: vic

Bobnoxious
10-26-2018, 08:15 AM
Please share your solution?