C12 UV filter box

[Jeremy Parrett]

2000 Marquis C12 455 hp turbo.
There is a 3ft x 4in x 1 ft black box between the side air intake and the Donaldson air filter container.   Can I remove this system to vastly improve the air flow to the engine???
Label says it contains a UV detectable dye medium!

[Gerald Farris]

Jeremy,
You are talking about the air intake duck, and rain water seperator. It is not a restriction for the air intake and should not be removed. The label that you are talking about is not referring to the air intake, but it is referring to the UV dye that was added to your dash A/C refrigerant.

Gerald

[Jeremy Parrett]

Gerald.
 this box is after the side mounted air inlet box with the drain in it bottom. The flex tubing from the side inlet goes to this slim 3 ft high by 4 inch deep and 1 ft wide box,mounted vertically on right side rear of engine compartment. The air ducting flex hose goes into this box at the top and exits at the bottom and then goes to the Donaldson drum air filter.  A label on the box says something about UV detectable dye media.......which must be inside this box. Will post pics today so you can see what it looks like.

[Edward Buker]

Jeremy,

My guess is that someone modified your system and used this as a means to either straighten the existing hose by passing it through it or they actually made an air box with fittings for clamps on the ends to try and improve flow and your hose was shortened on both ends to connect it. I think the UV Dye label was an original use of the box and has nothing to do with the air inlet. I assume this box is metal. I think Gerald has hit the nail on the head regarding the original use of the dye in his note. Normally this is just a flexible duct run.

Later Ed

[Jeremy Parrett]

Gerald,
 here are 4 pics of this mysterious box.  As you can see from pic 1 I have added a Caterpillar coolant expansion bottle after reducing the rad cap to 7 lbs on the expansion tank.  It is worth noting since I did this I have added 2 litres of coolant to this bottle as air trapped in the high pressure system has found its way out.
Pic 2 shows the flex ducting coming from the C12 side air intake to this black box
Pic 3 shows the label on the black box
Pic 4 shows the underneath of the black box where the flex ducting exits the black box to the Donaldson drum air filter housing.
Pic 5 is a closer look at the engine compartment.
   My brother inlaw is a diesel engineeer and he has no clue as to what this unit is !!!
  

[Jeremy Parrett]

Here is another pic of the lower end of the black box where the air duct leaves it and goes to the Donaldson air filter .
 I cant wait to read your comments on what this unit might be !!!

[David T. Richelderfer]

My guess, as Gerald pointed out, it's a rain water separator.  Your air intake is on the side of the coach, open to the outside air with no hood or cover.  When you are driving in a rain event, your engine would be pulling in air AND WATER from the rain.  The black box is there to let the liquid water settle out and not continue into your air filter and engine.  I understand a little water in the fuel entering combustion chambers might enhance combustion, but too much will ruin the engine... and will especially be hard on diesel engines.

My coach has a much smaller black box (4" thick by 12 " wide by 15" tall) standing vertically immediately behind the wall where the air intake point is on the side of the coach.  I tried to feel along the bottom of the black box for a drain hole.  I didn't feel one.  The other thing that puzzles me is the black box on my coach is only a few inches wide and stands vertically between the intake and duct to the air filter.  That makes the air filter inlet duct attachment point on the black box only 5 or 6 inches from the outside air intake point.  That would not seem to me to be enough distance for the liquid water entering with the air intake point to separate and fall out.  Oh well...  I gave my two-bits worth.

[Jeremy Parrett]

David,
  The air enters the side of the coach through a grill into a box with a rubber drain flapper valve. This box is 16 inches long,12 inches wide and 8 inches high. The air passes over the base with the flapper/drain  valve and then up to a separate chamber This eliminates any possibility of water entering the engine. The air is then ducted from this inlet box to the mysterious black box,from that to the Donaldson filter ,then to the turbo.

[Gerald Farris]

Jeremy,
There is no mysterious black box. You posted a picture of the air duct. The center section of the duct is made of sheet metal to provide a durable duct for a restricted area to route the air from the inlet box on the side of the coach to the air cleaner that is mounted below it. There is nothing inside the duct. It is a hollow air duct only, and replacing it with another duct would be a waste of time and money.

The label that you are referring to has nothing to do with the air duct. The label was just installed on the duct because it was a convenient, flat area to place the label to notify a technician that may be looking for a leak that UV dye has been installed in the system that is marked on the label.  

Gerald

[Jeremy Parrett]

Gerald,
That is good news.  So,if I remove this unit and replace the flexible ducting with new , I can definitely improve the air flow  from the inlet box to the Donaldson filter canister,by eliminating the sharp turns in the air flow as it runs through this box.  
In any case I am going to remove it just to check if it is actually a pre filter of some sort.

[Jim Nichols]

From the pictures it looks to me like there wasn't enough room width wise to run the flex tubing. I do not have a c12 but did have flex tubing squeezed to an oval in 3 places which created a restriction showing on the meter. I changed to all sheet metal with a small amount of flex. I doubled the incoming cfm and improved performance. I think a lot of coaches could use incoming air improvements.