If you drive a diesel truck in Phoenix, AZ, you already know how hard these engines work.
3A Automotive & Diesel Repair has been the trusted diesel repair shop for drivers across North Phoenix, Sunnyslope, Moon Valley, Deer Valley, and the surrounding area since 1975. Conveniently located on Hatcher Rd, we serve diesel truck owners throughout the Valley.
Here are the most common diesel engine problems, and what you should actually do about them.
What Are the Most Common Diesel Engine Problems?
There are several diesel problems that people bring their trucks in for. The main one is when the diesel has a check engine light on. Usually, when people try and diagnose something by themselves when there is a check engine light, that really leads into other problems. Diesel parts are very expensive, and if you are just throwing parts into the truck to try and fix the problem, that is going to get really expensive.
Other common issues include:
- Running Problems: This includes cases where the engine is not giving you the power that you are used to or it is hesitating.
- DEF System Issues: Problems with the diesel exhaust fluid system are very common. These usually require someone who has the proper tooling to be able to diagnose what the problem is.
How Can You Tell If Your Diesel Needs Professional Repair?
Typically, when there is a running problem or there is a check engine light of some sort on, that is when you want to go with a professional. You need somebody who has the proper equipment and the proper training to diagnose what is going on with the diesel.
The challenge is that when you start throwing parts at a diesel, it gets very expensive fast because the parts in these trucks are pretty expensive. If you do not know specifically what is causing the problem, you might throw several parts in it and it still has the same problem because it was not properly diagnosed.
What Are the Warning Signs of an Injector or Fuel System Issue?
Problems with your injectors or the fuel system typically start with some kind of a long crank when you are trying to start the vehicle. You might also notice a misfire, or run into power problems where you get a little bit of a hesitation when you put your foot on the gas.
Other warning signs include:
- Black Smoke: This happens because the system is dumping too much fuel into the engine.
- Frequent DPF Regeneration: You may experience too frequent diesel particulate filter regeneration. This happens because too much fuel is being sent into the system, which clogs up that filter and causes it to want to regenerate all the time.
Why Does a Diesel Engine Blow Black Smoke — and When Should You Worry?
Diesel engines typically blow black smoke when they are on a heavy acceleration. This happens when your foot is in the gas because you want to pass somebody, or you are carrying a heavy load up a hill. This is totally common as you are putting a lot of fuel into the engine.
You should be worried about this when it does not go away after acceleration. If you are not into the gas and it is always blowing black smoke, that tells you that you want to have a professional look at it because that is a deeper problem. This can be caused by problems with the injectors, a fuel system putting too much fuel in, or the engine not getting enough air — and sometimes something as simple as a bad air filter.
What Causes a Diesel Engine to Overheat?
One of the most common things that causes a diesel engine to overheat is not having enough airflow going through the cooling system. In a diesel, you have the radiator up front and these trucks collect bugs and debris which blocks that airflow.
Other things that can cause overheating include:
- Gelled Coolant: If the cooling system has not been flushed often enough, coolant can get gelled up inside the radiator and prevent proper flow.
- Bad Fan Clutch: The fan clutch regulates how fast the fan spins. If it goes bad, it is not spinning fast enough and is not pulling enough air through the radiator.
- Low Coolant Levels: This could be because of an air pocket in the system after a change, or a slow coolant leak that has reached a point where the radiator is low.
How Can You Tell If It’s the Glow Plugs or the Battery?
- Battery Issue: You will know it is a battery issue if the engine is just not cranking over fast enough. You have to have a lot of RPMs to be able to start a diesel.
- Glow Plug Issue: If it is cranking over really fast and it is not starting in cool weather, that could be a glow plug issue. The engine block is not getting heated up enough to actually ignite that diesel fuel.
A red flag is if the truck was starting fine when it was warm out, but now it will not start when it is cool.
What Are the Most Costly Diesel Repair Mistakes?
The most costly thing you can do is throw parts at a problem rather than getting it properly tested by a professional. This can get very expensive fast because diesel parts are pricey.
Another costly repair is when somebody runs gas through their diesel by mistake. If this happens, the tank needs to be drained and you need to put fresh diesel in the system.
The most expensive mistake is putting diesel exhaust fluid (DEF) into the fuel tank. If that fluid gets poured into the diesel, it crystallizes. If you turn that key on and the fuel pump pumps it into the injectors, you might have to replace everything from the tank up to the fuel injectors. If you make this mistake, you must stop, take the key out, and do not do anything.
Get Your Diesel Diagnosed Right the First Time
3A Automotive & Diesel Repair has been serving Phoenix diesel owners since 1975.
If you’re in North Phoenix, Sunnyslope, Moon Valley, Deer Valley, or anywhere across the Valley, call us at (602) 888-0588 or visit 1539 W. Hatcher Rd, Phoenix, AZ 85021.
Open Monday–Friday, 7:30am–5:30pm.
