Tech Tips

The following technical tips provide repair information about specific conditions on a variety of vehicles. If you have a tough or unusual service repair, the TSS Technical Assistance Hot Line can help. Call 1-800-825-5886, prompt #2, to speak with a technical expert with the latest OEM information.

Aluminum Heater Core and Radiator Replacement

2005 and prior GM passenger cars and light-duty trucks

 

It may be necessary to replace an aluminum heater core, radiator or water pump due to erosion, corrosion or insufficient inhibitor levels in the coolant. A coolant check should be performed when replacing these components in order to verify proper coolant effectiveness.

 

Verify coolant concentration using a refractometer. A 50% coolant/water solution ensures proper freeze and corrosion protection. The refractometer uses a minimal amount of coolant that can be taken from the coolant reservoir, radiator or engine block. If the concentration is below 50%, the cooling system should be flushed.

 

In addition, verify that no electrolysis is present in the cooling system using a digital voltmeter. The electrolysis test can be performed before or after system repairs. Electrolysis is often an intermittent condition that occurs when a device or accessory that is mounted to the radiator is energized. This type of current could be caused by a poorly grounded cooling fan or other accessory and can be verified by watching the voltmeter while turning on/off various accessories or engaging the starter motor.

 

Follow the flushing procedures outlined in the Service Information for vehicles using DEX-COOL^® coolant and for vehicles using conventional silicate coolant.

 

Do not mix the OEM orange colored DEX-COOL coolant with green colored conventional coolant. Some GM vehicles, such as the 2004-2005 Chevrolet Aveo use a blue colored conventional coolant.

 

 

Engine Mount Replacement

 

2004-2007 Cadillac CTS with 3.6L (LY7) or 2.8L (LP1) engine

 

When replacing the engine mounts for any reason, follow these steps to prepare and install the new mount.

 

The new part does not include the exhaust heat shield which must be re-used.

 

Follow the appropriate Engine Mount Replacement procedure in SI to remove the old mount from the vehicle.

 

Once the mount is removed, mark the hole location of the alignment pin on the mount heat shield. (Fig. 14, A)

Using a suitable tool, remove the retaining spring nut from the top of the mount heat shield and discard the old mount. (Fig. 14, B)

 

Prepare the replacement mount by cutting the lower locating pin off using a die grinder and cutting wheel. (Fig. 15, A)

 

Align the marked hole on the heat shield with the top alignment pin on the replacement mount. (Fig. 15, B)

 

Follow the appropriate Engine Mount Replacement procedure in the Service Information to install the new mount with heat shield into the vehicle.

 

Verify that the heat shield is properly located on the mount.

 

A retaining spring nut is not required.

 

 

Ignition Lock Cylinder

 

2008-2009 Cadillac CTS (built prior to VIN breakpoint 90163371), 2005-2009 Chevrolet Cobalt (built prior to April 14, 2009), 2006-2009 Chevrolet HHR and Pontiac Solstice (built prior to April 14, 2009), 2007-2009 Chevrolet Equinox (built prior to July 2008), 2007-2009 Pontiac G5 (built prior to April 14, 2009) and Pontiac Torrent (built prior to July 2008), 2006-2009 Saturn SKY (built prior to April 24, 2009) -- with an automatic transmission only

 

Technicians may experience some difficulty installing the new style ignition lock cylinder on these models.

 

Before installing the new cylinder, carefully inspect the housing for debris or damage from the old lock cylinder.

 

No tools are required for installing the new lock cylinder. When installing into the housing, ensure that the lock cylinder is fully seated to ensure it latches into position.

 

Do not use the old style lock cylinder that is still used on a manual transmission-equipped vehicle on a vehicle with an automatic transmission; the original binding condition will likely return.

 

Refer to GM bulletin #09-02-35-005A for additional information.