6.5L Diesel Oil Change Parts List
Part Description |
Part Number(s) |
Remarks/Notes |
Engine oil filter |
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Oil pan drain plug gasket |
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Oil fill cap |
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|
Engine oil |
Refer to viscosity chart below |
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6.5L GM/Detroit Diesel Oil Selection, Requirements, & Recommendations
The 6.5L GM diesel has a relatively small engine oil capacity at 7 quarts (8 quarts for 1999+) with a filter change. For comparison, the 6.6L Duramax has a 10 quart system. Even though the 6.5L has an oil cooler, the oil in these engines may have a tendency to degrade quicker and have a relatively low resilience to fuel dilution and other forms of oil contamination due to the limited capacity. Heat also plays a large role in the degradation of engine oil, which ultimately modifies its properties.
A synthetic oil is your best choice for any engine, and thus remains our recommendation for the naturally aspirated and turbocharged 6.5L diesels. There's no special procedures for converting to a synthetic engine oil and synthetic service fluids are far superior to conventional petroleum based "dino" oils. Albeit slightly more expensive, synthetic oils tend to provide a greater level of protection for your engine.
6.5L GM Diesel Viscosity Chart
Viscosity |
Ambient Temperature Range |
SAE 15W-40 |
> 0° F (preferred) |
SAE 30W |
> 32° F (15W-40 preferred over 30W) |
SAE 10W-30 |
< 32° F (cold weather viscosity) |
While a straight 30 weight oil is acceptable in ambient temperatures greater than 32° F, 15W-40 is largely preferred and recommended in place of a SAE 30W. 10W-30 must be used when the engine is operated in ambient temperatures below 0° F and can be used in place of a 15W-40 when the ambient temperature is in the 0 to 32° F range. Engine oil should be changed every 5,000 miles under normal conditions and 2,500 miles under "severe" duty conditions, which includes frequent towing, extended periods of idling, off-road use, etc.
6.5L GM Diesel Engine Oil Recommendations
Diesel Hub recommends the following Amsoil products for GMC and Chevrolet vehicles equipped with a 6.5L diesel:
Amsoil Max Duty Signature Series 15W-40 diesel oil
Premium full synthetic motor oil for severe duty service and maximum wear protection
Amsoil Heavy Duty 15W-40 diesel oil
Economical engine oil option offering advanced wear protection
Amsoil Max Duty Signature Series 10W-30 diesel oil
Premium full synthetic motor oil for maximum protection in cold temperatures
Amsoil synthetic engine oils offer:
• Superior protection against fuel dilution and oil consumption
• Superior resilience against thermal, mechanical, and chemical breakdown of engine oil
• Improved oil flow and engine protection in sub-zero temperatures and during cold starts
• Advanced protection for vehicles that stored periodically or driven in-frequently
Amsoil is a leading manufacturer of synthetic oils and lubricants, including a line of engine oils engineered to meet the stringent demands specific to diesel engines.
How to Change the Oil in a 6.5L GM Diesel
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• Place a suitable container beneath the engine oil pan (minimum 8 quarts capacity) to catch the oil as it drains.
• Remove the oil pan drain plug with a box end wrench (in this case a 9/16" or 14mm wrench, however the actual size of your plug may vary - it may have been replaced, etc) and allow the engine oil to drain completely. The drain plug points to the driver side of the vehicle.
• While the oil is draining thoroughly clean the drain plug with a lint free rag. Inspect the drain plug gasket and replace as required. The best practice is to replace the drain plug gasket at every oil change. Replace the drain plug and tighten snug once the engine oil has drained completely.
• Reposition the drain pan as necessary and remove the engine oil filter. An oil filter wrench may be required to loosen it. Another method of getting a better grip on the filter is to wrap it with emery cloth or sand paper - especially useful if the filter is slick with oil.
• The engine oil fill cap is located at the front of the engine, just to the passenger side of the thermostat housing. Removing or loosening the cap may help the oil drain quicker, but make sure to place a rag over the fill tube if you remove the cap completely.
• Using a lint free rag, clean the oil filter mount where the gasket of the oil filter seals against the oil filter mount. Inspect the mount and make sure that the old oil filter gasket did not stick to the sealing surface; this is very common and will result in a compromised seal when the new oil filter is installed.
• Fill the replacement oil filter with roughly 3/4 of a quart of oil. The filter will hold approximately 1 quart of oil, however if it is filled to the brim you are likely to spill it when installing the filter.
• Thoroughly lubricate the oil filter gasket with clean engine oil.
• Reinstall the oil filter. Hand tighten snuggly; do not tighten with oil filter wrench.
• Add 7 quarts for pre-1999 and 8 quarts for 1999+ model year engines (minus the amount added to the oil filter) of new motor oil to the crankcase through the oil fill tube at the front of the engine.
• Verify the engine oil level using the oil dipstick.
• Ensure the oil fill cap is secure and that the engine oil drain plug is not leaking, then start the vehicle and check for leaks at the drain plug and oil filter.
• You can't go wrong with an OEM ACDelco oil filter. This truck received 7 quarts of Amsoil Heavy Duty 15W-40 motor oil and is ready for severe service.