Melted box in engine compartment.

[Paulhowell]

Our coach is in the shop for annual service. It's a 40ft, 1999 Patriot Thunder with a 425hp C12 Cat and the 4000 series Allison transmission. The service advisor sent me this picture of a gray box that appears to be melted. I'm not sure what this box controls and how severe the damage is. I'm going to go check it out on Tuesday and see if I can figure out what it is and if it can be repaired. Does anyone know which  system this box is associated with?  Thanks.

[Dave Atherton]

Paul, can you give me your C-12 engine S/N number. Than also in center of picture there is
Fitting attached to turbo hot side that has a part number with red line going to it. The number
looks like you can read . This will be helpful in answering your question.
Dave Atherton Retired Cat Mechanic

[Paulhowell]

Thanks Dave. I'll pick up the coach on Tuesday and send that info then.

[Edward Buker]

Paul,

It looks like an electrical 120V junction box with some connection wire nutted inside. When the box gets replaced I would fashion a sheet metal heat deflector between the turbo and the new box to reduce the direct radiant heat from reaching the plastic. Some additional suitable insulation on the backside (box side) of the metal deflector would be wise. Wiring areas that have seen this kind of heat may have caused the wire and/or the wire insulation to become brittle and possibly resistive. Whoever does the works needs to examine that possibility and assure the wiring condition is still acceptable. 

You might check if there is any 120V house wiring that is likely to be in that area from the backside, if you cannot see external wires entering from the engine compartment.

Later Ed

[Fred Brooks]

   Hi Paul,
  The j-box has something to do with 120 volt electrical. Trace your shore cord coming from your power reel or it could be the J-box from your engine block heater. Either way, it looks like the "melted part" was created externally from an exhaust source.
 My coach had a melted wire nut in my J-box and I lost half of my 120 volt power coming into the coach. Make sure the coach is NOT plugged in or generator running before you jump in and investigate.
   Regards, Fred Brooks

[Dave Atherton]

Paul, Fred, Ed,  what both of you are saying makes sense, ( house power shorted ). The big
concern now that time is passing by why would anyone at a mfg level put a plastic J-box above
or right on top of the hot discharge side of a turbo charger with engine encased under the house.
My little motorhome had a similar occurrence happen and caught fire. With membership
owning Beaver motorhomes there now seems several problems mfg wise starting to occur.
The  forum has pointed several out. But this one stands out if correct diagnostic, that will burn
down the house. Note: turbocharger under load all day if you look at your turbo in evening
you will see dull orange color of the turbo housing, yes the turbo housing discharge side is
hot. Next point of concern debris falling in and around turbocharger will melt or burn. Paul
Looking at that one part number ( last post ) will verify if aftermarket add on equipment has
been and is related to the box. Dave Atherton Retired Cat Mechanic

[Paulhowell]

Thanks Dave!

[Paulhowell]

Thank you Ed and Fred.