Mazda 6 Service Manual: No.19 exhaust smoke

No.18 cooling system concerns-runs cold

No.20 fuel odor (in engine compartment)

Other materials:

Mazda 6 Service Manual: Engine removal/installation
Warning Fuel vapor is hazardous. It can very easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injures or death and damage. Fuel can also irritate skin and eyes. ...

Mazda 6 Service Manual: Foreword
When the customer reports a vehicle malfunction, check the malfunction indicator lamp (MIL) indication and diagnostic trouble code (DTC), then diagnose the malfunction according to following flowchart. - If a DTC exists, diagnose the applicable DTC inspection. (See DTC TABLE.) - ...