Diesel Engine Oil Service for NEWMAR KING AIRE
This comprehensive guide will walk you through repairing diesel engine oil service on your NEWMAR KING AIRE. Follow each step carefully and gather all required parts before beginning.
Required Parts
- 15W-40 diesel oil – 28-32 quarts
- Oil filter – Cummins 3401544
- Fuel filters
Step-by-Step Instructions
Step 1: Pre-Service Preparation and Warm-Up
Proper diesel engine oil service on the Newmar Dutch Star begins with appropriate preparation and understanding of the engine’s specific requirements. The Dutch Star typically uses either a Cummins ISB 6.7L or ISL 8.9L engine, both of which are inline-six turbo-diesel engines with substantial oil capacities (28-32 quarts). Unlike smaller gasoline engines, these diesel engines require extended warm-up before servicing to ensure complete oil drainage and accurate fluid analysis. Start the engine and allow it to reach full operating temperature, which takes approximately 15-20 minutes of idling or a short drive. Warm oil flows more freely and carries more contaminants in suspension, ensuring better drainage. While the engine warms, gather all necessary supplies and locate the oil drain plug, oil filter, and fuel filters. The engine compartment on a Dutch Star (as with all diesel pushers) is at the rear of the coach, accessed through a large rear panel or hatch. Ensure adequate ventilation in this area as diesel exhaust contains harmful gases. Prepare your workspace with the oil drain pan, tools, and new filters within easy reach.
Step 2: Accessing Engine Compartment and Safety Considerations
Access the engine compartment of the Newmar Dutch Star by opening the large rear access door or panel. The Cummins diesel engine will be immediately visible, along with the Allison transmission, radiator, and other components. Diesel engines run extremely hot, so after warm-up, turn off the engine and allow 10-15 minutes for components to cool to safe handling temperature – the exhaust manifold and turbocharger can exceed 400°F and cause severe burns. Put on nitrile gloves to protect your hands from hot oil and diesel fuel. Locate the oil drain plug on the underside of the oil pan – you might need to crawl underneath the motorhome to reach it. The drain plug on Cummins engines is typically located at the rear-center of the oil pan and requires a 1″ or 24mm socket. Position your large-capacity drain pan directly under the drain plug, accounting for the fact that the oil will initially shoot out with some force due to the large volume being drained. Have plenty of shop towels handy as diesel oil service is invariably messy.
Step 3: Oil Drainage and Analysis
Using the appropriately sized socket (typically 1″ or 24mm), carefully loosen the oil drain plug while supporting it with your hand to prevent it from falling into the drain pan once threads are clear. As soon as the plug is free, quickly move your hand away as hot oil will begin flowing immediately. The initial oil flow from a Cummins diesel is substantial – expect 28-32 quarts to drain, which takes 10-15 minutes to complete fully. While oil is draining, observe its condition carefully. Healthy diesel engine oil should be very dark (nearly black) but should flow smoothly without chunks, excessive metallic particles, or unusual smell. A milky appearance indicates coolant contamination (likely a blown head gasket or oil cooler failure), which requires immediate professional attention. Metallic particles or glitter in the oil suggest bearing wear or other internal engine damage. Fuel smell in the oil indicates injector leakage. Once drainage slows to occasional drips, wipe the drain plug and inspect the copper crush washer – replace it if it’s compressed, cracked, or damaged. Clean the drain plug threads with a cloth and apply a small amount of anti-seize compound to the threads (not the washer). Reinstall the drain plug and tighten to the specified torque (typically 45-55 ft-lbs for Cummins engines – do not overtighten).
Step 4: Oil Filter Replacement
Locate the oil filter on your Cummins engine – it’s typically mounted on the driver’s side of the engine block and is a large canister filter (approximately 6-8 inches long and 4-5 inches in diameter). Position your drain pan beneath the filter as a quart or more of oil will spill when you remove it. Using a large oil filter wrench, turn the filter counterclockwise to loosen it. Once the seal breaks, you can usually remove the filter by hand. As you unscrew the filter, tip it slightly to minimize spillage. Inspect the engine block where the filter mounts for the old filter gasket – occasionally the rubber gasket sticks to the block rather than coming off with the filter. If the old gasket remains on the engine, carefully remove it with a rag or plastic scraper as installing a new filter on top of an old gasket causes leaks. Clean the filter mounting surface with a lint-free cloth until smooth and clean. Take your new filter and apply clean diesel engine oil to the rubber gasket, coating it completely – this ensures proper sealing and prevents the gasket from sticking during future removal. Thread the new filter onto the engine by hand, turning clockwise until the gasket contacts the mounting surface, then continue turning an additional 3/4 to 1 full turn. Do not use a filter wrench to tighten – hand-tight plus 3/4 turn is sufficient and prevents over-tightening that can damage the filter.
Step 5: Fuel Filter Service
While performing oil service, it’s an ideal time to service the fuel filters since you’re already in the engine compartment and the service intervals are similar (typically every 15,000 miles or annually). Cummins diesel engines use a two-stage fuel filtration system: a primary filter/water separator and a secondary final filter. Locate both filters – they’re typically mounted on the driver’s side of the engine and are connected by fuel lines. Start with the primary filter (water separator). Place a drain pan beneath it and open the drain valve at the bottom of the filter housing to drain any accumulated water – diesel fuel naturally attracts water, and this water must be removed regularly to prevent injector damage and engine problems. Drain until only clear diesel fuel (no water) flows from the valve. Close the drain valve securely. Using a filter wrench, remove the primary filter by turning counterclockwise. Install the new primary filter using the same procedure as the oil filter: coat the gasket with clean diesel fuel, hand-tighten until the gasket contacts the mounting surface, then turn an additional 1/2 to 3/4 turn.
Step 6: Secondary Fuel Filter and System Priming
Move to the secondary (final) fuel filter and replace it using the same procedure as the primary filter. Here’s where diesel engine service differs significantly from gasoline engines: after replacing fuel filters, you must prime the fuel system to remove air. Air in a diesel fuel system prevents starting and can damage the injection pump. Cummins engines typically have a hand-primer pump integrated into the fuel system – locate this pump (it’s usually near the fuel filters or on the fuel filter housing) and operate it according to the manufacturer’s procedure. Typically, this involves loosening the secondary filter slightly, then pumping the primer until fuel flows from around the filter threads (indicating air is purged), then tightening the filter. Continue priming until the primer offers significant resistance, indicating the system is fully pressurized. Some Cummins engines are self-priming and don’t require manual priming – consult your engine manual. If your engine doesn’t have a primer pump, you might need to crank the engine for extended periods (15-30 seconds at a time with 30-second cooling intervals) to allow the electric fuel pump to purge air and prime the system.
Step 7: Engine Oil Refilling and Final Checks
With all filters replaced and the drain plug secured, you’re ready to refill the engine with fresh oil. Locate the oil fill cap on top of the engine (typically on the driver’s side valve cover). Remove the cap and insert a long-spout funnel. Begin pouring fresh 15W-40 diesel engine oil into the engine. For a Cummins ISB, you’ll need approximately 28 quarts; for an ISL, approximately 32 quarts. Add oil slowly to avoid overflow – these engines have large capacities, and it’s easy to overfill. After adding the specified quantity, wait 2-3 minutes for oil to drain into the oil pan, then check the dipstick (located on the driver’s side of the engine). The oil level should be between the “ADD” and “FULL” marks on the dipstick. Add more oil if necessary, checking frequently to avoid overfilling (overfilling can cause oil foaming and inadequate lubrication). Once the oil level is correct, replace the oil fill cap securely. Start the engine and let it idle for 30 seconds, then shut it off. Wait 2-3 minutes for oil to drain back into the pan, then recheck the oil level with the dipstick and adjust if necessary. Check underneath the motorhome for oil leaks at the drain plug and oil filter. Record the date, mileage, and details of the service in your maintenance log. Properly dispose of used oil at a recycling center or automotive service facility – never pour used oil down drains or on the ground.