For 1990-2009 cars

# EFFECTS OF TOP ENGINE CLEANER CARBURETED ENGINES

Top Engine Cleaner (TEC) is effective in cleaning deposits from engine components. GM part number 1050002, 1052626 or their equivalents may be used for this process.

Although TEC does not affect catalyst performance when used as directed, misuse of the product may result in appreciable losses in catalytic converter efficiency due to high temperatures caused by the extra rich mixture. For this reason, TEC must be used according to its label with particular attention to the following:

1. Allow the engine to run at idle for ten to fifteen minutes before adding TEC.

- This will allow the converter to stabilize at a lower temperature and, thus, minimize the chance of thermal degradation upon introduction of TEC into the system.

2. Divert the AIR from the converter in the following manner:

- Electrically disconnect the A.I.R. divert solenoid (connector with two pink/black wires).

- The AIR system uses an engine driven pump to inject air into either the cylinder head exhaust ports, the catalytic converter, or the air cleaner. The air management valve performs the air switching and divert functions. De-engerizing the AIR divert valve solenoid diverts the air to the air cleaners and blocks the flow of air to the converter. This prevents air from being injected into the converter while TEC is being added, reducing the possibility of excess TEC being ignited in the catalytic converter.

3. Add TEC at a slow, steady rate.

- This allows excess hydrocarbons to be burned off smoothly keeping converter temperature to a minimum.

4. Restore AIR management system function as follows:

Electrically reconnect the AIR divert solenoid (connector with two pink/black wires).

Use of TEC in accordance with these instructions as well as the label instructions permit effective performance of the product without damaging the catalytic converter.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.