ENGINE DIAGNOSTIC TEST PROCEDURES Section 6 • AIR CLEANER MAXIMUM RESTRICTION 400 Series On-Highway (with Robert Bosch MW Pumps) FROM FORM NO. CGED-365 AIR CLEANER MAXIMUM RESTRICTION* 7 A. MEASURE AT FULL LOAD AND RATED SPEED INSTRUMENT GUIDELINE DATA‚ 1st CHECK 2nd CHECK WATER MANOMETER OR MAGNAHELIC GAUGE p Refer to "Performance Data Guidelines", in this section. NOTE:  -  Often  a  low  power  and  poor  fuel  economy complaint is simply due to a dirty air cleaner. In this test,  the  gauge  probe  is  inserted  in  the  air  intake system  downstream  of  the  air  cleaner.  As  the  air cleaner   accumulates   dirt,   restriction   to   air   flow increases.      If   restriction   exceeds   the   guidelines, clean or replace the air cleaner element or elements. Inspect Air Intake Restriction 1. Refer   to   appropriate   "Operation   and   Maintenance Manual"        "Air        Cleaner        Restriction    Gauge    and Indicator," for detailed information. NOTE: - The air cleaner is to be serviced only when the restriction reaches the maximum allowable limit. The   restriction   can   be   measured   by    a    service indicator, vacuum gauge or a water manometer. 2. Inspect the element(s) for damaged gaskets or dents in the element(s). If they exhibit either they should be replaced. Single Element Air Cleaner Measure air cleaner restriction as follows: 1. Attach restriction test (vacuum) gauge (4, Figure 14) at air cleaner (3). 2. Run    engine    at    full    load    and    rated    speed    (for turbocharged engines) and at High Idle speed (RPM) (for N/A engines). 3. Service air cleaner element when vacuum gauge (4, Figure 14) shows 6.2 kPa (25 in. H20) for turbocharged engines. 4. Service air cleaner element when vacuum gauge (4, Figure 14) shows 7.0 kPa (30 in. H20) for turbocharged engines measured at the TurboInlet (2, Figure 14). 5. Maximum air cleaner restriction can only be obtained when engine is running at full load and rated speed. If    measuring    air    cleaner    restriction    under    these conditions is not possible, run the engine at high idle no load.  Under these conditions, the reading will be approximately   1/2   the   full   load   reading.   Maximum allowable restriction is 6.2 kPa (25 in H20) under full load    and    rated    speed;    therefore,    the    restriction reading  at  high  idle  no  load   should   be   no   greater than   2.9    kPa    (12    in    H20).        Service    air    cleaner element   when   maximum   air   cleaner   restriction   is reached. NOTE:  -  TURBOCHARGED  MODELS  ONLY  High  air cleaner  restriction  can  cause  turbocharger  seals  to unseat  causing  oil  to  be  drawn  through  seals  and into engine. DUAL ELEMENT CLEANER The  duel  element  air  cleaner  provides  a  large  primary (outer)    filter    element    and    optional    small    secondary (inner) filter element.  The secondary element should be used   in   dusty   environments   such   as   dump   and   mixer applications. The    current    dual    element    air    cleaner    assembly    air cleaner  restriction  connection  (1,  Figure  15)  is  located between  the  primary  and  the  secondary  element  (2)  in the bottom of the air cleaner housing (3). This arrangement  allows  only  the  primary  (outer)  element  to be  sensed  by  the  restriction  indicator  or  dash  mounted vacuum    gauge.         THE   INNER   ELEMENT   IS   NOT RECORDED  ON  THE  RESTRICTION  INDICATOR  OR DASH MOUNTED VACUUM GAUGE. CGES-240-4 Printed in United States of America Page 23