ENGINE OVERHEATS (Cont) - TM-9-2320-285-24-10057

TM 9-2320-285-24-1

2-11. COOLING SYSTEM TROUBLESHOOTING (CONT)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1. ENGINE OVERHEATS (Cont)

Step 14. With engine temperature below 180 degrees F, connect ohmmeter across thermal switch terminals

(thermal switch lead remains disconnected at thermal switch.) Ohmmeter should indicate zero ohms

with engine cool. Start engine and watch WATER TEMP gage; when gage indicates 195 degrees F,

ohmmeter should indicate open circuit (infinity).

a. If ohmmeter does not indicate zero ohms when engine is cool, or does not indicate open circuit

(infinity) when WATER TEMP gage indicates 195 degrees F, replace thermal switch (para 2-15e).

b. If ohmmeter indicates zero ohms when engine is cool, and indicates open circuit (infinity) when

WATER TEMP gage indicates 195 degrees F, disconnect ohmmeter from thermal switch and

reconnect thermal switch lead (para 2-15e). Then go to step 15.

WARNING

Wear safety glasses, and stand clear of loosened air line fitting. High pressure air can

propel debris at high speed, causing eye injury or blindness.

Step 15. With key switch turned to on position, engine shut down, and at least 100 psi pressure in air system,

carefully disconnect air line from outlet side of solenoid.

a. If air escapes from solenoid, solenoid is defective; replace (para 2-15e).

b. If air does not escape from solenoid, go to step 16 below.

Step 16. Have assistant momentarily turn key switch to off position. Watch solenoid.

a. If air does not escape from solenoid, replace solenoid (para 2-15e).

b. If air escapes from solenoid, notify direct support maintenance (refer to TM 9-2815-205-34 for

troubleshooting of the engine and its components).

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