I changed my air filter on my frtliner fld120 when i replaced it I noticed it had a arrow with the word inlet which way does the arrow go when you placed the filter in the case.

air flows the direction of the arrow, so......





which way do you want the air to flow?

While I'm not familiar with the exact setup on your Freightliner, some Mack air filters are similarly stamped "inlet" with an arrow.

When installing those, the arrow should point toward the air inlet in the filter housing.

shouldn't it point towards the outlet? ie - direction of airflow?

No, Bob, not on the Mack CH, CL models, the element fits in to the housing and is secured by three retaining clips that snap over center to hold it in.

On the end is stamped "inlet", and this must point to the air inlet in the outside of the filter housing. The "outlet" is in the end of the housing, and the filter element has a gasket that seals it at that point.

As I said, I'm not familiar with Vontrials particular setup, but I thought this sounds similar. He stated that his filter is stamped "inlet" also.

understood. sounds like a typical filter housing, except that there's something different about the filter... is it a normal pleated paper media?

bob h wrote:Yes, a typical paper filter, with an opening on one end that registers with the opening in the end of the housing, where the ductwork feeding the turbo is connected.

The other end of the element has the steel flange that the 3 clips latch onto in order to retain it in the housing.

On the steel flange is the word "inlet" and an arrow stamped in the metal.

This arrow must point toward the air inlet on the outside of the filter housing, which is at approximately a 1 o'clock position when viewing from the end. This air inlet then indexes with the ductwork built into the fibreglass hood in order to draw intake air thru the louvers in the sides of the hood.

It's a pretty foolproof system, no retaining nuts to strip , can be changed in a couple of minutes.

Takes longer to wipe the dirt out of the housing with a damp rag than it does to actually R&R the filter element.

Thats the same as on my Freightliner with the detroit engine. Three clips line up to attach to the filter housing and the arrow pointing about the 1 0'clock position. Inlet being right below the middle of the windshield.

Frank.

Hey Thanks everyone for the info I do have the arrow pointed in the 1o clock postion. Thanks again