Maintenance Tips
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Have you been looking for ways to get more mileage from your diesel  truck and
reduce operating costs?

Here are some tips that can extend your engine life and reduce the costs of
maintaining your truck.
"Cleanliness is next to godliness"
This saying is particularly true for diesel engines. 
The four systems of air, fuel, coolant, and lubrication are all essential to a healthy engine and vehicle.

Keeping these systems immaculate can significantly extend the life of your vehicle and reduce operating costs.
Replacing filters and fluids regularly is much cheaper than replacing engines, injector pumps, and transmissions.

Maintenance Calendar
Make up a maintenance calendar for your vehicle and keep it in a conspicuous location. Stay on schedule as much as
possible. This simple idea is widely neglected by many people, and as a result, many vehicles do not receive
adequate maintenance. Make sure you go by the manufacturer's recommendations and not the dealer's.

General Maintenance
Quite often the most effective preventative maintenance is also the simplest
1. Check oil and coolant levels frequently. Notice the color and texture of the oil and coolant
2. Check transmission fluid, power steering fluid, and brake fluid periodically. Check for any unusual color or odor.
These fluids are often neglected and need to be replaced at appropriate intervals
3. Check radiator cooling fins frequently for bug build up and clean if needed.
4. Check condition and tension of fan belts periodically
5. Check condition of hoses periodically
6. Check air filter and air intake components regularly
7. Check for air, fuel, oil, and coolant leaks. Replace coolant filter periodically. See the recommended interval in your
coolant filter kit instructions.
Heat and friction are the two biggest enemies to your engine.

Using a coolant filter, flushing the cooling system, and changing the coolant and filter on a regular basis can go a long
way in extending engine and water pump life and avoiding very expensive repairs. Make sure you always use the
recommended type of antifreeze.
8. Check electrical connections, especially at the battery or batteries
9. Check tire pressure periodically and adjust if needed. Inspect tire condition for any potential problems
10. Make sure all gauges are in good working order
​11. Inspect glow plugs periodically (if applicable to your vehicle)
12. Check transfer case fluid and differential fluid regularly

Cooling System

In the old days of diesel cars and trucks, coolant had one major duty: keep the engine cool. Nowadays coolant must
take on extra duties which means even greater demands on the cooling system than ever before.     

Engine coolant in many diesel engines takes on the additional role of controlling oil temperature as well as EGR

For extended engine life and optimum performance, cooling systems must be maintained in excellent working
condition. Regular inspections and replacement of coolant, filters, hoses, and other components can help greatly in
keeping the cooling system in top shape.                                               

1. Coolant Filter. 
Did you know that most big rigs come with a coolant filter as standard equipment?
So what does a coolant filter do and why may I need one?

Coolant filters are designed to filter out particles that end up in coolant such as sand and small metal particles from the
manufacturing process and rust and sludge from coolant breakdown.

Antifreeze has a limited life and will deteriorate over time. Antifreeze has an alkaline pH when new which helps protect
the engine metal from oxidation.

When the coolant becomes more acidic over time, the increased acidity begins to corrode the engine metal and
produces rust.

Another side effect from antifreeze breakdown is sludge and chemical buildup which collects in radiators and engine
surfaces, and reduces the ability of the coolant to control the engine temperature.

Diesel engines are particularly vulnerable to overheating. Cooling is a critical aspect of engine operation.

A coolant filter can minimize problems with the cooling system and extend the life of the water pump, as well as help
prevent radiator and other orifice clogging.

If your truck does not come equipped with a coolant filter, it will be necessary to install a coolant filter kit as an
aftermarket add on. Check with your diesel mechanic to determine if a coolant filter will benefit your vehicle.

As a general rule, the newer the vehicle is when the coolant filter is installed, the more the vehicle will benefit from the
filter. Older vehicles may still benefit as debris from coolant breakdown, mineral deposits, and rust formation can still

Some diesel engines are cast in sand during manufacturing. Even after extensive washing, some sand particles
remain and leach out from the metal over time.

A problem that is even more prevalent is silica in the antifreeze that separates out when the antifreeze breaks down

Small metal particles also end up in the coolant, especially when a vehicle is new. A coolant filter installed when a
vehicle is new will trap most of these particles before they damage the water pump or engine.

It is recommended to change the filter after the first 3000 miles or so, because that is when the most particles will be
collected in the filter. After the first filter replacement the interval can usually be lengthened. Check the
recommendations that come with the filter kit for specifics.

A coolant filter can filter out particles such as sand, rust, metal, dirt, and chemical sludge.
​  It is not a replacement for changing coolant periodically, which leads us to the nest tip.

2. Flush coolant system and replace coolant periodically.
Each manufacturer recommends replacing coolant at specific intervals, usually at least every 50,000 to 75,000 miles.
Some manufacturers recommend coolant change every 30,000 miles. Check your owners manual.

3 Use antifreeze that is compatible with your vehicle. A mix of 50/50 is optimum for cooling and anti-corrosion capacity.

4. Should I use distilled water or tap water in my radiator?
The answer to that questions depends on the hardness of the water where you live. Hard water can certainly cause
mineral deposits which can clog radiators and reduce cooling capacity. Distilled water will prevent or reduce mineral
build up, but is slightly acidic. Check with your diesel mechanic for recommendations for your specific vehicle.

5. Cavitation.
Cavitation is caused by coolant bubble implosion during engine operation. Engine vibration creates small vapor
bubbles in the coolant.   When these bubbles implode, strong shock waves are created which can damage engine
metal. Extreme heat is also generated which can cause local damage. This is called cavitation erosion. The use of
Supplemental Coolant Additives (SCA) can prevent or reduce this type of damage.

Consult your diesel mechanic to see if using SCA is appropriate for your vehicle.          

Fuel System

"An ounce of prevention is worth a pound of cure". 
When it comes to the fuel system, the best policy is to keep the fuel squeaky clean.

​1. Drain the water from the water  separator periodically. Diesel fuel frequently contains small amounts of water which
can damage diesel engines. 
  Water found in diesel fuel collects in the water separator. If your diesel  truck does not have a water separator,
consider having one installed.

2. Use quality fuel filters and replace filters at recommended intervals. Most diesel engines are equipped with both a
primary and a secondary filter. A common rating for the primary fuel filter is 30 microns, and  2 microns for the
secondary filter.
Any particles not filtered out of the diesel fuel can cause damage to the fuel injectors or injector pump. Those are not
cheap to replace.
Damage to the engine block is also a possibility.

3. Keep the fuel tanks above half full as much as possible. When your vehicle will be sitting for any length of time keep
the fuel tank(s) full. This will reduce water condensation in the fuel tanks.

4. Diesel fuel differs in quality. Buy fuel from a reputable dealer. It will pay off in the long run. Also avoid fueling soon
after a fuel truck has transferred fuel into the underground tanks. The fuel transfer may cause sediment to be stirred up
from the bottom of the storage tank. 

The best time to fuel up is in the early morning. Diesel fuel is more dense the colder it is, so you actually get a little
more for your money. Also, the fuel should have fewer contaminants due to the impurities settling to the bottom of the
tank overnight. (Providing a fuel truck hasn't delivered fuel in the early morning).

5. Use winterized diesel fuel to prevent gelling and wax build up in cold weather

6. Fuel additives. Fuel quality can differ considerably from dealer to dealer. With changes in diesel fuel to facilitate
lower emissions, the diesel fuel composition has changed, and some of that effect is reduced lubrication ability of the
fuel.   In today's fuel environment, a fuel additive is highly recommended, and many mechanics and truck drivers
consider fuel additives a necessity. Diesel Kleen, Red Line, and Stanadyne are good quality additives.

7. Cetane booster. Is it necessary to use cetane boosters?
Most engines will benefit from the use of a cetane booster.
Cetane boosters will shorten the combustion delay of the diesel fuel and will usually improve the engine operation.
Increasing the cetane number beyond the manufacturer's  recommendation  will not improve vehicle performance.

Oil Filtration

Diesel engines operate under high compression which results in a small amount of fuel that slips past the piston rings
and accumulates in the engine oil.

Filtration is highly important in diesel engines. A standard 25 to 30 micron filter used in gas engines won't cut it for a
diesel. Many mechanics recommend an oil filter of 7 microns or smaller and some even recommend filtration at 2
microns. Engine wear is directly related to particle size that is allowed through the filter. See the following article:

Check with your owners manual and your mechanic for recommendations.

Spokane Diesel Truck Repair
23514 N Austin Rd
Colbert, WA 99005


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