General Motors — Out-Of-Season Engine Storage
Maintenance
From a General Motors owner's manual covering: Carb 5.7L, MP 5.0L, MP 5.7L, MP 6.0L. Check it applies to your exact model before use.
Before you start
- On fuel injected engines, you MUST bleed off fuel pressure before proceeding.
- Operate the bilge blower and be sure no fuel vapors are present when treating the engine.
- Excess storage oil in the engine's cylinders can cause hydrostatic locking.
Procedure
- Fill the fuel tanks with gasoline and add a sufficient amount of gasoline stabilizer such as STA-BIL.
- Remove, empty and clean the fuel filter assembly; reinstall with a new fuel filter and gasket/seals.
- Run the engine to normal operating temperature (minimum 10 minutes); shut down and change the oil and oil filter.
- Flush the cooling system if operating in salt water or brackish water areas.
- Restart the engine and allow it to idle for 5 minutes.
- Turn off the ignition and remove the spark plugs; spray fogging oil into each cylinder and turn the crankshaft several revolutions by hand.
- Install the spark plugs and connect the spark plug wires.
- Remove and clean the flame arrestor and vent hoses and reinstall; cover the throttle body assembly.
- Close the fuel shut-off valve (if equipped).
Tools required
- aerosol-type fogging solution Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: General Motors owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.