Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

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Bench Test

BENCH TEST






1. Drain all coolant from the heater core.
2. Connect the 101.6 mm (4 in) test heater water hoses with plug and adapter to the core tubes. Then connect Rotunda Radiator/Heater Core Pressure Tester or equivalent to the adapter.
3. Apply 206 kPa (30 psi) of air pressure to the heater core with Rotunda Radiator/Heater Core Pressure Tester or equivalent and submerge the heater core in water.
4. If a leak is observed, repair or replace the heater core as necessary.