C18 Marine Engines Coolant Sample (Level 1) - Obtain Caterpillar

Coolant Sample (Level 1) - Obtain

Note: Obtaining a Coolant Sample (Level 1) is optional if the cooling system is filled with Cat ELC (Extended Life Coolant). Cooling systems that are filled with Cat ELC should have a Coolant Sample (Level 2) that is obtained at the recommended interval that is stated in the Maintenance Interval Schedule.

Note: Obtain a Coolant Sample (Level 1) if the cooling system is filled with any other coolant instead of Cat ELC. This includes the following types of coolants:

  • Commercial long life coolants that meet the AVSpare Engine Coolant Specification -1 (AVSpare EC-1)

  • Cat DEAC (Diesel Engine Antifreeze/Coolant)

  • Commercial heavy-duty coolant/antifreeze

Table 1
Recommended Interval 
Type of Coolant  Level 1  Level 2 
Cat DEAC  Every 500 Hours(1)  Initial 500 Hours and Yearly(1)(2) 
Cat ELC  Optional(2)  Initial 500 Hours and Yearly(2) 
(1) This is the recommended interval for coolant samples for all conventional heavy-duty coolant/antifreeze. This is also the recommended interval for coolant samples of commercial coolants that meet the Cat EC-1 specification for engine coolant.
(2) The Level 2 Coolant Analysis should be performed sooner if a problem is suspected or identified.


Always use a designated pump for oil sampling, and use a separate designated pump for coolant sampling. Using the same pump for both types of samples may contaminate the samples that are being drawn. This contaminate may cause a false analysis and an incorrect interpretation that could lead to concerns by both dealers and customers.

Note: Level 1 results may indicate a need for Level 2 Analysis.

Illustration 1g01942100
Coolant sampling valve on bottom of the inlet bonnet for the oil cooler

The coolant sampling valve for the engine coolant is located on the right side of the engine on the inlet bonnet for the oil cooler.


Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.

Refer to Special Publication, NENG2500, "Cat Dealer Service Tool Catalog" or refer to Special Publication, PECJ0003, "Cat Shop Supplies and Tools Catalog" for tools and supplies suitable to collect and contain fluids on Cat products.

Dispose of all fluids according to local regulations and mandates.

Obtain the sample of the coolant as close as possible to the recommended sampling interval. In order to receive the full effect of S·O·S analysis, must establish a consistent trend of data. In order to establish a pertinent history of data, perform consistent samplings that are evenly spaced. Supplies for collecting samples can be obtained from your AVSpare dealer.

Use the following guidelines for proper sampling of the coolant:

  • Complete the information on the label for the sampling bottle before you begin to take the samples.

  • Keep the unused sampling bottles stored in plastic bags.

  • Obtain coolant samples directly from the coolant sample port. You should not obtain the samples from any other location.

  • Keep the lids on empty sampling bottles until you are ready to collect the sample.

  • Place the sample in the mailing tube immediately after obtaining the sample in order to avoid contamination.

  • Never collect samples from expansion bottles.

  • Never collect samples from the drain for a system.

Submit the sample for Level 1 analysis.

For additional information about coolant analysis, see this Operation and Maintenance Manual, "Refill Capacities and Recommendations" or consult your AVSpare dealer.

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