For 1990-2009 cars

# Engine Runs Hot, Overheats, Loss of Coolant (Polish Filler Neck/Replace Radiator Cap)

Subject: | Engine Running Hot, Overheating and/or Loss of Coolant (Polish Radiator Filler Neck and Replace Radiator Cap)

Models: | 1999-2000 Passenger Cars and Trucks

| with Composite Radiator End Tank

### Condition

Some customers may comment on one or more of the following conditions:

• | Engine running hot

• | Engine overheating, and/or

• | Loss of coolant/low coolant message

### Cause

The radiator filler neck may have an imperfection in the sealing surface.

### Correction

Important: DO NOT REPLACE THE RADIATOR.

Using a piece of 400 grit wet/dry sandpaper backed with a flat piece of wood, polish the filler neck sealing surface using a circular motion.

Replace the radiator pressure cap with a cap of the same part number as shown in the GM Service Parts Catalog.

### Warranty Information

For vehicles repaired under warranty, use:

Labor Operation | Description | Labor Time
--- | --- | ---
J3020 | Cap, Radiator Filler - Replace | 0.2 hr