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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Heater Core: Testing and Inspection




1. Using a special tool, install to the heater core one side and the other side is clogged.
2. Place the heater core in water, then apply 200 kPa (29 psi) pressure.
3. Holding for two minutes, while checking for leakage from the heater core. If there is leakage, repair or replace the heater core.