Coolant Leak (Repair or Replace Coolant Cap)

Some customers may comment on the following conditions:

The check valve in the coolant pressure cap may not work properly. The valve may not have been centered correctly when the cap was assembled by the vendor.

Caution: With a pressurized cooling system, the temperature of the coolant in the cooling system can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the system is hot and under pressure, causes the solution to spew out over the engine, the fenders and the person removing the cap. Serious bodily injury may result.

Inspect the coolant recovery cap pressure relief valve for correct operation, using one of the following procedures ("A" or "B" below):

Using the cooling system pressure tester J 24460-01 and adapter J 42401-1, follow the steps below:

1. Remove the cap from the surge tank (coolant reservoir).
2. Inspect for the presence of (2) O-rings around the outside of the cap mechanism. If not present, replace the cap with P/N 22652695.

If the cap fails the test, firmly press on the center of the valve with the eraser end of a pencil. Compress the spring about 6-7 mm (¼ in) and release. This should center the valve.

3. Retest. If the cap fails again, replace the cap with P/N 22652695.

If the special tools in Procedure "A" are not available, follow the steps below:

1. Remove the cap from the surge tank (coolant reservoir).
2. Inspect for the presence of (2) O-rings around the outside of the cap mechanism. If not present, replace the cap with P/N 22652695.
3. Place the cap on a bench with the label down. Fill the center, above the brass valve, with water. If you can completely fill the center section and it holds the water, the valve is working properly. If the water drains from the center section, firmly press on the center of the valve with the eraser end of a pencil. Compress the spring about 6-7 mm (¼ in) and release. This should center the valve.
4. Retest. If the water is now retained by the center section of the cap, the cap is repaired. If not, replace the cap with P/N 22652695.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: