B: INSUFFICIENT, ERRATIC, OR NO HEAT

Pinpoint Test B: Insufficient, Erratic, or No Heat

B1 CHECK FOR PROPER ENGINE COOLANT LEVEL

- Check engine coolant hot and cold.

- Is engine coolant at proper level (hot/cold) on radiator coolant recovery reservoir?

- Yes
Go to B2

- No
Go to B3

B2 CHECK FOR HOT WATER TO HEATER CORE INLET HOSE

- Start engine and allow to reach normal operating temperature.
- Feel heater core inlet hose.

- Is the heater inlet hose hot?

- Yes
Go to B4

- No
Refer to Engine, Cooling, and Exhaust/Cooling System/Testing and Inspection. Testing and Inspection

B3 CHECK COOLANT SYSTEM INCLUDING RADIATOR CAP FOR LEAKS

- Fill coolant system to specified level
- Pressure check coolant system using Rotunda Radiator/Heater Core Pressure Tester 014-R1054 or equivalent. It is not necessary to check components separately at this time.

- Does coolant system including radiator cap hold pressure?

- Yes
Go to B4

- No
Service engine cooling system. Refer to Engine, Cooling, and Exhaust/Cooling System. Cooling System

B4 CHECK HEATER CORE OUTLET HOSE FOR HOT WATER

- Engine operating at normal operating temperature.
- Feel heater core outlet hose.

- Is heater core outlet hose cool or cold?

- Yes
Service heater core for plug or partial plug.

- No
Refer to Heating and Air Conditioning/Testing and Inspection for Manual or Electronic Climate Control systems. Testing and Inspection