C15. MBN prefix. Dump truck Truck looked to be pretty heavily loaded with 3/4 base. And was about 4 miles up a decent grade. Damage looked pretty minimal. Plastic air duct, couple of air lines and ac hoses. And of course some loss of the hood insulation. So, I patched up the airlines and sent the truck back to the base yard. Trying to figure cause and effect. It looks like an ac line blew and sprayed the turbo. But I have never heard of r134a catching fire. I spent a few minutes searching the internet. It is supposed to be non-flammable. I think I read somewhere that it could be flammable when mixed with pressurized air (I think also oil) and a strong ignition source. Strong ignition source would be the turbo. Figure with where it was that the turbo was easily over 600 degrees F. So, where is the pressurized air. Pretty sure the fan clutch would be fully locked up. But isn't that just air volume? Not sure if I would consider that pressurized. Anyone have any thoughts?
We need some pictures to determine guilt.
Turbo was probably in the 800*F area. It lit the oil in the 134. Seen this happen with a COE years ago it had R12. If it was night time and no hood to spoil view that turbo would be a nice dull red. * Some years ago a cat house in south Seattle caught fire, a truck was pulled into a bay after just completing a road test hood was just opened, the truck in the next bay sprang a fuel leak which sprayed directly on the turbo of hot one that just came off the road, and it was guessed that it was around 550* at that moment.
Yeah, sorry. I didn't take any. It was raining pretty hard when we got back to the yard. What I can tell you is that it definitely looks like the ac hose ruptured. Don't see any scorching on it. And the turbo looks to have been sprayed with pag oil and ac dye. But I will get you some pics. I probably won't get down to that yard until Monday. No emergency on my part because I won't let them run the truck until I can replace the intake duct. And they won't want to run it until the ac gets fixed. Oh... Hmmm. (smacks head). I might have just figured this out. Ac compressor oil is flammable and the only point in the system lower than than the ruptured hose is the receiver/dryer. That at least seems plausible. I'll post some pics soon and wait to see what you all think.
It's the culprit.
Thanks. That's a great answer. Sorry that my last post seems to ignore your reply. I was typing while you were posting.