Taking a good coolant sample using a vacuum pump.

If the cooling system is not equipped with sampling valves, coolant samples should be drawn from the radiator. While taking coolant samples from a radiator, please observe safety precautions. The sample should be taken after the coolant has been well circulated. However, do not remove the radiator cap if the coolant is hot. The best time to take samples is after the engine has been shut down for an hour or two after a normal workday.

Carefully remove the radiator cap to take the sample. Use the same steps as the oil sample (vacuum pump) method.

Caution, samples drawn from the overflow tank or the system drain valve will not be representative of the fluid in the cooling system.

Always use a separate vacuum extraction pump for coolant samples. Although the fluid does not enter the barrel of the pump, samples may indicate compartment contamination. Vacuum pumps that contain residue from coolant samples may indicate coolant contamination in oil samples. Vacuum pumps that contain oil residue may indicate oil entry into the cooling system. Designate a separate pump for coolant samples.