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2013 MRU613, roughly 6000 miles mp7 Allison auto front load garbage truck. The problem is the air filter is filthy, like crazy filthy looks like soot. Anybody ever see or hear of a problem like this. Also notices the screen for the the intake is plastic mesh and has gotten hot enough to shrink.

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Sure looks like like it ran reversed

"OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK"  Thomas Edison

 “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’

P.T.CHESHIRE

Looks like the cab guard is causing the exhaust to get trapped and recirculate into the intake, probably while you are stopped loading or unloading, I would remove the stack top and replace it with a 90 degree elbow and pipe to vent it to the outside. I know the trucks here are set up that way for that reason, the stack top on your truck is actually not made for enclosed areas it is made to disperse the high heat exhaust gas in a wide area so it cools faster, it works great when its out in the open but not so much trapped under there it again disperses the gas in a wide area so in that configuration it will get pulled right into the air intake.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

Thought about the body causing some sort of flow restriction or rerouting the exhaust. It not like this is the first front loader made so I kinda figured any problems like that would have been sorted out. When the truck regens the exhaust temp is hot hot enough to prob melt paint or cause some other problem. Also the cab guard has a cut out above the stack. The truck runs a tight route in town daily and runs to the landfill(40 miles one way) on the highway.

It is a 2013 model with a DPF. Very little if any soot should be exiting the exhaust pipe. No soot should be passing thru the DPF even druing regen. My guess is the DPF filter is cracked or defective and it is sucking in soot. Is the filter covered with soot or black from getting too hot? Let us know what the dealer finds.

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Ken

PRR Country and Charter member of the "Mack Pack"

Yeah the exhaust cutout is there for a vertical pipe cut that thing a few inches under the diffuser and add enough pipe to get it up in clean air. Just having a cutout doesn't do much if the pipe is a foot under it and exits thru he side not the top, your cooking your air filter and the high intake temps are gonna kill your engine before too long.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

Ballard seems to think its from a sitting regen, but the only time it ever sat during regen was there one time. They took pics and are going to talk to "the factory" also, another hauler has the same truck/body configuration and doesn't have a problem...I think I'm gonna take it in the shop and try to locate the dpf filter as mentioned above.

the dpf filter is the muffler one section is the particulate filter the other is the catalyst and then you have the scr chamber, if you remove the stack top with the diffuser on it and put a pipe on it that goes up to thje cutout in your cab guard youll fix the issue, but hey its a whole $40 bucks for a stick of pipe to try it and see if it works or not. go look at the other trucks exhaust configuration see if the stack is the same length or has a different tip, I would extend the stack to get it out of the cab guard and swap the air filter and I bet the filter stays clean and your engine temp goes down too.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

I will be traveling tomorrow to investigate the ther truck that Mack speaks of both to confirm the configuration and to take measurements on the stack. Thank you, though an obvious easy fix its def better to hear it from an unbiased source. Again thank you

Looks like it was ran backwards!! I know the old ones would do that but don't know about the new electronic ones ?

Yes they will, i luged my 98 e7 down the other day on a hill and it rolled backward and fired up and smoked out the hood, but it did not do it but a few sec. I had a little to much wegiht on here and was trying to let a loader operator get out of my way without stoping and haveing to pull out on a grade, i know rookie stuff right!!

All MRU's and LEU's have that same stack, there should be no reason to change it. There are 1000's of the same trucks out there running just fine with the OEM stack. You do have an unusual problem that will require a dealer service with Mack tech support. Is there any signs of soot inside the exhaust pipe or around the exhaust? I would think that if exhaust is coming form your stack it would be visiable on the white paint. There should be 0 signs of soot anywhere. Anys signs of soot means the DPF filter is cracked. Assuming there is no signs of soot around the stack they might just replace the air filter, repair/replace the air intake, let you run the truck and keep an eye on it.

We do get soot visible on the white paint and the driver says when the truck regens the rear glass is hot to touch.

What you describe sounds like a cracked or defective DPF. Per earlier post, the inside of the stack should be clean...no black soot.

Ken

PRR Country and Charter member of the "Mack Pack"

The first MRU frontloaders we sold back in 2008 were melting the plastic worklights and anything that was not made of metal under the cab protector. The bed company usually had a hole in the cab protector for the conventional muffler pipe to come up through. They were afraid that trash would fall through the hole onto the hot DPF and catch fire. So they put a block off plate over the hole. Now the heat from the DPF when regening was trapped under the cab protector and started melting anything near by. As per Macks instructions we removed the block off plate and put a piece expanded wire over the hole to allow the heat to escape and not let trach fall ontop of the DPF. Thoses 3 trucks are still running fine today with no issuses. However with the SCR now added and the different position of the exhaust piping thing are quite different. And as everyone said it could be a cracked filter.

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