Common Diesel Engine Issues to Watch Out For

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If you’re looking for the best brand for heavy equipment, you only need to think of one brand: Caterpillar. One of the Fortune 500 companies, Caterpillar is the leading construction equipment manufacturer in the world. It spends billions in research and development to ensure its products are innovative, functional, and easy to use.

One of its most popular products is the diesel engine: powerful, well-designed, and cost-effective. But even the best can have problems.

Listed below are some of the common issues you encounter with a diesel engine. Although you can fix some of them, calling an expert in Caterpillar diesel engine repair prevents costly mistakes.

1. Difficult Start

Your diesel engine may be difficult to start for many reasons. A poor battery connection leads the list of common causes. But you can check quickly and easily by yourself.

However, problems related to fuel delivery are next on the list. If you have a dirty air filter, it can contribute to difficulty starting as well. For this reason, it’s important to have your air filter inspected regularly.

Also, a faulty glow plug wiring harness, a problem with the relays, and an air pressure issue can all contribute to starting trouble. To resolve this, have the glow plugs checked and replaced if necessary.

2. Engine Knocking Noise

Problems with the engine’s timing system can lead to a knocking noise. This usually manifests itself as a loud thumping noise coming from the engine.

First, you must identify whether this is inside or outside the car and what it sounds like. If the problem is inside your car, disconnect one of the battery terminals. If you can still hear a knock after a minute, this points to a problem with the fuel pump or timing system.

Otherwise, if all is quiet after disconnecting one of the battery terminals and you can identify that it’s coming from the engine bay but only at idle speed, then it’s likely an issue with your turbocharger. This could be as simple as a loose heat shield.

3. Excessive Smoke from Tailpipe

The smell of diesel smoke usually signals a fuel delivery problem. If you smell the smoke, check for leaks in the area where your fuel lines connect to the engine and tank. You should also get your fuel filter checked.

If there is no visible leak or you cannot get any gasoline out by squeezing the lines, then it’s likely a blockage in your fuel injectors. In this case, try removing and cleaning them.

4. Incorrect Fuel Additives

Diesel engine additives are common, so you might think adding another bottle of something to your fuel tank can only help. However, this is not necessarily the case.

Using incorrect additives can damage your fuel system or cause inaccurate readings that lead to other problems. For example, biodiesel (which is often touted for its “green” benefits) does not burn well in an engine designed for petroleum diesel.

If you use biodiesel, you may experience higher-than-normal carbon buildup in your engine or difficulty starting. Some additives are just fuel, so be sure the product you use is approved for your diesel engine.

5. Excessive Vibration

car parts

An unusual amount of vibration coming from under the hood can also signal problems. A worn engine mount may be to blame here. But there are other possibilities too—for example, a power steering pump that’s not properly mounted or a loose alternator belt or slipping could also cause vibration issues.

To repair, replace or fine-tune your power steering pump mount, alternator belt tensioner mount, and engine mounts.

6. Poor Idle Quality

A rough idle quality is often attributed to problems with the fuel injectors or the fuel pump. If you suspect either of these, it’s necessary to have your diesel mechanic test them for you.

7. Excessive Fuel Consumption

Compared to gas, diesel is more economical and fuel-efficient. If your diesel engine is being unusually thirsty, you need to figure out why.

The more common causes are a plugged fuel filter, dirty injectors, or a defective glow plug wiring harness. You can also watch for signs of a worn turbocharger and check the air pressure in the top cylinders. Don’t forget to check the oil and fuel for contaminants.

8. Loss of Engine Power

If you feel like you’re losing power when driving, it could be an indicator of a problem, but the issue may not be what you think. A clogged air filter or fuel filter can lead to reduced power, which means replacing the filter is likely the best course of action.

However, it may be that your air or fuel filter wasn’t the issue at all. You just need to get your engine’s timing and/or injection adjusted. (This is because poorly timed and incorrectly injected fuel can dilute the lubricating properties of diesel engine oil.)

9. Lackluster Driving Performance

Let’s start with the basics: Make sure that your engine oil level is full. You can add oil when needed, but be sure to check it periodically anyway. A low oil level makes for difficult driving performance just as it would in your car.

You also need to check the oil level in the turbocharger. If you don’t, it could overheat. When that happens, you need to fix it fast! Driving with faulty turbocharger cooling can lead to an expensive repair bill.

Diesel engines are more efficient and powerful, but they can also be complicated. If you’re having problems with your diesel engine, the best course of action is to have it thoroughly inspected by a professional mechanic.

But it also helps to know how to tell if something is wrong. Use this list as your guide.

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