Checking Engine Coolant
Check the engine coolant level in the reservoir by removing the reservoir cap. Check the reservoir indicator while the engine is cold. The coolant level should be at or above the COLD mark on the indicator when the engine is cold. At normal operating temperatures, the engine coolant level should be at or above the HOT mark on the indicator.
Add engine coolant only to the reservoir in order to raise the level to the appropriate mark. Use a 50/50 mixture of DEX-COOL™ engine coolant and water whenever you add coolant.
Engine Coolant Concentration
This test is done by using a refractometer engine coolant tester. Refractometers test for the amount of glycol in a coolant mixture by measuring the speed of light as light passes through the fluid and is not affected by the specific gravity of the glycol. Refer to Coolant Concentration Testing .
Hoses and Clamps Inspection Procedure
| • | Inspect the condition of all hoses and clamps. Hoses should be flexible and show no signs of bulging. |
| • | Inspect the hoses for cracks, kinks, and areas of possible leaks. |
| • | Inspect the hose brackets, supports, ties and clamps. |
| • | TIghten and adjust the components as needed. (The spring clamps are not adjustable.) |
Water Pump Coolant Seepage
During vehicle operation, a slight amount of seepage may occur at the water pump vent hole. Tracks of residue may occur from the lower vent hole. If coolant is dripping from the vent hole while the engine is in operation, or while the cooling system is pressurized, replace the water pump.
Adding two sealant pellets to the cooling system may correct minor water pump seepage and minor engine cooling system leaks. These pellets are available from GMSPO in packages of six under GM P/N 3634621.
Add two engine coolant supplement pellets to the cooling system under the following conditions:
| • | A vehicle encountering water pump seepage or minor coolant leak/loss that you cannot correct through normal service procedures. |
| • | When the cooling system is drained and the coolant is replaced with new coolant due to major engine repair work, or at recommended coolant change intervals; 5 years or 100,000 miles (160900 km). |
| • | Whenever you replace the water pump. The addition of pellets provides a mild lapping of the new water pump seal that improves the adhering of the mating surfaces. Adding the pellets minimizes water pump seal seepage. |
Caution: In order to help avoid being burned, do not remove the radiator cap while the engine and the radiator are hot. Scalding fluid and steam can be blown out under pressure if the cap is removed too soon.
Important :
• Do not add pellets into non-pressurized coolant recovery bottles. • If pellets have been installed to correct an excessive water pump
seal seepage condition, one to two weeks of normal vehicle operation may be
required to lap in the mating seal surfaces. • Some staining, due to minor seepage, may continue to occur. This
is considered normal.
The two pellets should be installed into the radiator. Use care in order to avoid contamination of the radiator pressure cap and the sealing surfaces with pellet debris.
The use of sealant pellets may cause a film to appear around the sides of non-pressurized coolant recovery bottles. The presence of this film is considered normal.
After installing the pellets, run the engine for about 15 minutes. Then, check for coolant leakage and proper cooling system operation.
Radiator Cleaning
Notice: Do not spray cold water on a hot radiator.
Notice: The heat exchanger fins are necessary for good heat transfer. Do not brush the fins. This may cause damage to the fins, reducing heat transfer.
At least once a year, clean the front face of the radiator. On vehicles with air conditioning, clean the front face of the condenser. Remove any bugs, leaves, and other material by blowing compressed air from the rear of the radiator towards the front of the vehicle. If compressed air is not available, use a water hose to force water through the radiator from the rear toward the front of the vehicle. Use water only with the engine off and cool.
