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

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Thermostat Monitoring



Thermostat Monitoring

General description
After engine start and under the conditions:
- no hot engine
- ambient temperature within range
- normal driving
- sufficient mass air flow

an increase of the coolant system temperature will be expected.

Monitor structure
If the engine coolant temperature does not reach a certain value under normal driving conditions and sufficient mass air flow, the coolant system is defective.







flow chart: