826709109 Mercury NUT, (.250-28) Stainless Steel

Selection of Oil Change Interval
Refer to this Operation and Maintenance Manual, "Refill Capacities and Recommendations" for further information about oils that may be used in Caterpillar engines.Refer to this Operation and Maintenance Manual, "Severe Service Application - Check" to determine if oil change interval should be reduced from the normal change interval. If operating in any of the conditions or environments outlined in the Severe Service Application, use S O S Services oil analysis to determine the best oil change interval. If S O S Services oil analysis S is not being used, oil change interval should be reduced to 250 hrs.
Table 1
Oil Change Interval for C9.3 Industrial Engine (1)
Multigrade Oil Type Operating Conditions
Normal Severe Service Application
Cat DEO
or Cat DEO-ULS
Preferred 500 hr 250 hr
Oil meeting the requirements of the Cat ECF-3 Specification or the API CK-4 classification
8 minimum TBN
Preferred 500 hr 250 hr
Oil meeting the requirements of the ACEA C9/E6 Specification
TBN below 10.4 500 hr 250 hr
(1) The standard oil change interval in this engine is 500 hours, if the operating conditions and recommended oil types that are listed in this table are met. Ifthe type of oil, the quality of the oil and the operating conditions fail to meet certain standards, the oil change intervals must be decreased to 250 hours. Refer to Special Publication, PEHJ0192, "Optimizing Oil Change Intervals" in order to determine whether the oil change interval should be reduced to 250 hours.Drain the Engine Oil
After the engine has been run at the normal operating temperature, stop the engine. Attach a "DO NOT OPERATE" or a similar warning tag to the ignition keyswitch before the engine is serviced.
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.
Remove the oil drain plug to allow the oil to drain.
After the oil has drained, the oil drain plug should be cleaned and installed.Replace the Oil Filter
Caterpillar oil filters are built to Caterpillar specifications. Use of an oil filter not recommended by Caterpillar could result in severe engine damage to the engine bearings, crankshaft, etc., as a result of the larger waste particles from unfiltered oil entering the engine lubricating system. Only use oil filters recommended by Caterpillar.
Illustration 1 g00103713
Typical filter mounting base and filter gasket
Remove the oil filter with a 185-3630 Strap Wrench.
Clean the sealing surface of the filter mounting base. Ensure that all the old oil filter gasket is removed.
Apply clean engine oil to the new oil filter gasket.
Do not fill the oil filters with oil before installing them. This oil would not be filtered and could be contaminated. Contaminated oil can cause accelerated wear to engine components or engine damage.
Install the oil filter. Tighten the oil filter until the oil filter gasket contacts the base. Tighten the oil filter by hand according to the instructions that are shown on the oil filter. Do not overtighten the oil filter.Fill the Engine Crankcase
Remove the oil filler cap. Fill the crankcase with the proper amount of oil. Refer to the Operation and Maintenance Manual, "Refill Capacities and Recommendations" topic (Maintenance Section) for more information.
If equipped with an auxiliary oil filter or system, extra oil must be added when filling the crankcase. Follow the OEM or filter manufacturer's recommendations. If the extra oil is not added, the engine may starve for oil.
To help prevent crankshaft or bearing damage, crank engine to fill all filters before starting. Do not crank engine for more than 30 seconds.
Start the engine and run the engine at "LOW IDLE" for 2 minutes. Perform this procedure to ensure that the lubrication system has oil and that the oil filters are filled. Inspect the oil filter for oil leaks.
Stop the engine and allow the oil to drain back to the sump for a minimum of 10 minutes.
Remove the oil level gauge to check the oil level. Maintain the oil level between the "ADD" and "FULL" marks on the "ENGINE STOPPED" side of the oil level gauge.