1. General Check Over
A quick visual check can help to prevent future problems. Ask someone to sit in the truck and test the brakes, signals and reverse gear to ensure all lights are functional. The number of trucks that come in with burnt out light bulbs is quite astonishing. We recommend using a flashlight to look for any oily residue, buildup or leaks underneath the truck.
2. Fluids
To improve visibility, lift the hood and inspect the diesel engine. In summer, bugs and road rubble accumulate, so fill the washer tank, not always the cause of a blurry windshield.
Check the brake fluid, if it is low, it could be an indication that the system needs to be further looked at and could indicate other issues such as worn brake pads or possibly even a leak.
Check power steering fluid level not only is it responsible for the power steering, but also a critical part of the brake system providing assist on Duramax diesel trucks that use a hydro boost system instead of a vacuum assist as found on most passenger vehicles.
Pull the transmission dipstick as well if the truck is up to operating temperature. The truck should be idling and the transmission in Park when checking the fluid level. Even though there is a “hot” and “cold” range, we are looking for the fluid level to be at the bottom of the Hot range.
Verify engine oil level. Debates exist on how often to change it, each with distinct evidence. To know oil's remaining life, test it using our Fluid Analysis Kit. This not only tells you the oil is still good, but gives a full, understandable report on the engine's state.
The coolant level can be easily checked at a glance on your Duramax diesel by looking at the coolant surge tank. The tank will indicate where the level should be. Be sure not to remove the cap until you are certain the vehicle is completely cooled down. The condition of the coolant can be hard to tell visually but, just like the oil, it can be tested using just a small sample and our Coolant Analysis Kit.
The drive axles are an easily overlooked part of the driveline. While you have a dipstick or some type of low-level indicator on the dash for things like engine oil and washer solvent, the drive axle is easily forgotten about. Checking the fluid level is easy by simply removing the fill plug and ensuring the fluid level is at the correct level.
Rule of thumb is that the fluid would run out of the fill hole while sitting on level ground for a properly filled unit. While proper level is critical for long life, changing the fluid periodically is just as critical.
Many rear differentials are equipped with a traction lock device that uses small clutch plates to engage under certain conditions and the fluid quality and condition is critical to proper function. When servicing the rear differential, be sure to use a quality fluid that contains the correct additive for a limited slip, or an additive can be used. When it comes to checking a four-wheel drive truck, there should be no change when checking the front differential.
We recommend if you have a two-wheel drive truck; you can ignore this. Changing the fluid every 50,000 miles will prolong its life. We suggest Merchant Automotive Transfer Case Fluid; it combats wear, eliminates clunking, and improves engagement.
3. Filter
The summer heat is quite taxing on all parts of a truck. Depending on its year, it may have cabin air filters. Dirty filters are a result from blocked air vents, which can lead to bad smells. Replacement filters available for purchase!
The engine air filter is something that should be checked every time the diesel engine is serviced. Replace it if it's full of debris, but even if it looks clean, it could still be restricting valuable air flow into the engine. Replace it every 20,000 miles even if it doesn't look dirty to help ensure maximum life from your Duramax diesel. We have ACDelco air filters in stock for immediate shipment.
It's important to regularly change the fuel filter in diesel engines. The filter prevents water, dirt, algae, etc. from entering the fuel injection system, which runs at high pressure and is vulnerable to particles. At Merchant Automotive, we recommend changing the filter every 10-15k miles.
4. Tires
It is common for tires to lose air pressure over time if not checked regularly. While most modern trucks do have a tire pressure monitoring system (TPMS) you will want to check each tire periodically if you do not have TPMS.
One of the biggest causes of tire failure is over or under inflation. This is especially critical when towing or hauling additional loads in the bed. It is important to check your spare tire, it is often forgotten and neglected until you need it.
We recommend breaking out the tools that come with the truck to lower the spare tire. This allows you to be sure that the winch system is still functioning and not rusted up as well as take a quick look at the spare tire to ensure it is not damaged and will be ready if you need it.
Spray some lubricant in and around the spare tire winch to help prevent any corrosion that could render it useless when you need it the most. This also of course ensures that you do have the tools in the truck needed to lower the spare.
5. Trailering and Towing
Summer is the time for camping and other towing needs, likely one of the main reasons you bought a diesel in the first place! Inspect your hitch carefully against any rust or signs of fatigue, safety chain attachment points, and the trailer connector. That is a common place for corrosion build up as well as dirt and bugs to populate which would prohibit a good connection to your trailer. This could cause faulty lighting, or erratic trailer brake operation.
6. Additional Items
Over time, the cooling stack can become clogged with dirt, bugs, and road debris, reducing the airflow and hampering the coolers' ability to work properly. This can result in higher coolant and transmission temps, weaker air conditioning, and higher charge air cooler temps. See how bad it can be in this video: How-to properly clean the Duramax truck cooling stack - Mechanics Minute.
You can help prevent unexpected repairs and help prevent breakdowns with just a little effort and preventative maintenance. Merchant Automotive is here to help you out with your Duramax Diesel. Specializing in the Duramax since the company's inception and working on them since they first hit the market in 2001, you can count on Merchant Automotive to be the trusted experts for all things Duramax!
When your car has a service, make sure to inspect the engine air filter. Replace if clogged, even if appears clean, as it could block valuable air. Replace every 20,000 miles even when clean, to maximize Duramax diesel longevity.
