ARMY TM 9-2815-255-24 AIR FORCE TO 38G1-95-2 MARINE CORPS TM 2815-24/4 NOTE Pressure  checks  are  only  a  guide  to  determine  if  there  is  an  engine  problem  (valve  leakage, defective nozzles, etc).  Low readings are not a valid reason for increasing injection pump fuel delivery.  Pump adjustment should be within specification. c. Observe pressure reading on gage.  Reading should be at least 9 psi (60 kPa/0.6 bar) when engine is developing rated power at full load rated speed. d. If boost pressure is too high, remove and test fuel injection pump for high fuel delivery. e. If boost pressure is too low, check for the following: (1) Restricted air filter elements. (2) Restricted fuel filter elements. (3) Incorrect fast idle adjustment. (4) Incorrect injection pump timing. (5) Exhaust manifold leaks. (6) Intake manifold leaks. (7) Faulty fuel transfer pump. (8) Low compression pressure. (9) Faulty fuel injection nozzles. (10) build-up in turbocharger. (11) compressor or turbine wheel rubbing housing. (12) fuel injection pump fuel delivery. (13) exhaust. f. Remove test gage and install plug in intake manifold. Section IV.  COOLING SYSTEM MAINTENANCE 3-8.  GENERAL This section provides maintenance for cooling system components.  Components of cooling system not mentioned in this section can be found in the end item maintenance manual. Warning If  the  engine  has  been  operating  and  coolant  Is  hot,  allow  engine  to  cool  before  you  slowly loosen filler cap and relieve pressure from cooling system.  Failure to observe this warning could result In severe personal Injury. 3-9.  THERMOSTAT AND HOUSING. 3-9.1.  Removal. a. Drain coolant system if not already drained, refer to and item maintenance manual. b. Loosen hose clamp and remove outlet hose from cover (3, FIGURE 3-2). 3-20