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FTG Cycloflow™

The FTG Cycloflow™ is a two-stage axial seal air cleaner that is typically used in large engines operating in medium to heavy dust conditions.
FTG Cycloflow™ Air Cleaner is a two-stage air cleaner with built-in pre-cleaner.


  • Allows 32-59 m3/min / 1,130 to 2,083.6 cfm airflow throughput per air cleaner
  • Horizontal installation
  • Sustained temperature tolerance: to 82° C / 179.6° F
  • Large industrial and construction equipment: crawler tractors, crane loaders, excavators and air compressors with large engines operating in severe dust environments
  • Agricultural machinery  
  • Mining equipment
  • Oil and gas hydraulic fracturing (fracking) equipment
  • Off-highway vehicles


  • Durable housing withstands rugged conditions
  • Built-in pre-cleaner eliminates need for external pre-cleaner in most applications


  • Unique, flared inlet allows maximum airflow with low restriction
  • 533.4 mm / 21 in. in body diameter
  • Two-stage filter system — the first stage removes up to 85% of incoming dust with a tangential air inlet
  • Inlet on side, outlet on end
  • Already tapped to accept filter service indicator (1/8"-27 NPT MALE)
  • Safety filter protects engine inlet during filter change out
  • Vacuator™ Valve automatically releases the pre-cleaned dust
  • Housing is metal and coated with a black, corrosion- and chemical-resistant polymer paint
  • Mounting the unit directly to the engine is not recommended; excessive engine vibration can cause premature air cleaner structural failure
This servicing information is provided as a best practices guide. It is not intended to replace or supersede the service instructions supplied by your engine or vehicle manufacturer.

1. Check the Restriction
Check the restriction level of the air cleaner filter service indicator. Replace the filter only when the restriction level has reached the maximum recommended by the engine or equipment manufacturer or on a regular service schedule.

2. Clean Out the Vacuator™ Valve
Remove the Vacuator Valve and clean out any dust found in the drop tube. Reinstall Vacuator Valve or replace if found worn or damaged.

Note: Make sure the valve is flexible and not inverted, damaged or plugged. Replace it if damaged or if it looks like any of these images. A damaged or missing Vacuator Valve will disrupt the designed flow of air through the air cleaner. 


3. Gently Remove the Old Filter
Shut off the engine. Loosen and retain the wing nut bolt, remove bolt and washer. Replace both if damaged or worn.

Using the metal handle, pull the dirty filter gently from the housing. Accidental bumping will shake dirt loose inside the filter housing. 

4. Visually Check the Safety Filter
Visually check the safety filter without removing it. Replace if damaged or every three primary filter changes. Also verify that the safety filter is properly seated in the housing.

If the safety filter is to be replaced, it should be done immediately or the clean air outlet should be sealed. Use a clean cloth to avoid contaminant being introduced to the engine during service.


5. Always Clean the Inside of the Housing
Dirt left in the air cleaner housing is harmful to your engine. Use a clean, damp cloth to wipe the inside of the housing before fitting the new filter.

Block the outlet tube of the air cleaner with a small dampened towel prior to cleaning the seal surface to avoid contaminating the induction system. 

6. Clean the Gasket Sealing Surfaces 

An improper gasket seal is one of the most common causes of engine contamination. Make sure that all hardened dirt ridges are completely removed, both on the bottom and top of the air cleaner housing.

7. Inspect Your Old Filter and Check for Uneven Dirt Patterns 
Your old filter has valuable clues to dust leakage or gasket sealing problems. A dust pattern on the filter’s clean side is a sign that the old filter was not firmly sealed or that a dust leak exists. Identify the cause of any leak and rectify it before installing a new filter.

8. Inspect New Filters
Before installing the new filters, visually inspect them for shipping damage and gasket integrity. If a filter is damaged, do not install it. If desired, write the date of the filter change on the outer end of the filter end cap. 

9. Install the New Filters
First, if you’re servicing the safety filter at this change-out, seat it properly into position before installing the primary filter. Insert new filters carefully over the center bolt, hand tighten wing nut bolt for both filters. Make sure the primary filter gasket seats evenly to create a proper seal. If you don’t have a good seal, dirty air can by-pass the filter. 

10. Ensure an Air-tight Fit on all Connections and Ducts
Check that all clamps and flange joints are tight, as well as the air cleaner mounting bolts. Attend to any leaks immediately to avoid dirt entering your engine directly. Reset the filter service indicator.

Donaldson FTG & FLB Air Cleaners

Watch this Donaldson Engine - FTG & FLB Air Cleaner Series video for service steps.