Flushing the Coolant System

This process will be slightly different for each application, but the principles are the same.

Step 1.

Make sure the engine is cool enough to work with. Hot coolant can cause really bad burns!

Step 2.

Most engines can be drained nearly completely by removing the lower radiator hose at the radiator, and remove the reservoir cap to allow air in.

NOTE: On the VR6 engines there is a water pipe that runs along the front of the engine from the water pump to the thermostat housing. From below the car, there is a drain plug on this pipe. This drain plug MUST be removed along with the lower radiator hose to completely drain the system. There is nearly another liter of coolant in the block that will drain out here.

Step 3.

With the engine running at idle, run tap water through the reservoir. Keep the water flowing until clear water comes out the lower end of the radiator. It should only a take a few minutes. Don't drive with no coolant!

Step 4.

Reinstall the lower radiator hose and the drain plug if one was removed.

Step 5.

According to engine specifications and your climate, pour the coolant into the reservoir with the engine running. Fill with DISTILLED WATER ONLY. In order to completely fill the coolant system, the air must be purged out. The engine needs to warm up completely so that the thermostat will open and allow the coolant to flow. Watch the reservoir. As it lowers, keep adding DISTILLED WATER.

Step 6.

Go for a drive. Keep an eye on your temps. Top up the reservoir if needed!

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