While diesel engines require fewer repairs than gasoline engines, anything with moving parts is guaranteed to fail eventually. Even with regular maintenance, diesel engines can run into issues that need to be addressed promptly. Less they leave you stranded or turn into a more massive, more costly repair bill. Here are the top 8 most common diesel engine repairs that our certified diesel technicians carry out weekly.

Solving Fuel System Problems

Fixing fuel delivery issues are common diesel engine repairs and are not always easy to diagnose. Hard starting or lack of power are the first warning signs that something could be amiss with your fuel system. If your diesel engine is misfiring, sputtering at high speeds, surging, or simply will not start, this could also be a sign there are problems with your fuel system. The most common fuel system problem is a clogged fuel filter; however, it could be a defective fuel pump or malfunctioning fuel injector. Because issues with fuel delivery will cause your fuel injectors to starve, it is a that should have checked out immediately. Fuel delivery problems will not go away on their own and will continue to rob your engine of fuel mileage.

Replacing Faulty Fuel injector or Injector Pump

If you have a faulty fuel injector or injector pump, you will usually notice that your diesel engine is producing black exhaust. The black color from exhaust comes from an imbalanced air to fuel ratio, with your engine getting too much fuel and too little air. While diesel engines produce more exhaust than other vehicles, if your exhaust is black or has an excessive sulfur smell, not only are going to make fellow drivers unhappy, you could also face a fine for violating a clean air ordinance.

Replacing Glow Plugs

Diesel engines use glow plugs instead of spark plugs to warm diesel fuel so it can combust easier. If your glow plugs are bad or failing, the result will be a misfiring engine, excess smoke in your exhaust, or hard starting. Glow plugs in diesel engines typically last between 80,000 and 100,000 miles and are usually only replaced if one of them becomes problematic.

Replacing Lead-Acid Storage Batteries

Lead-acid storage batteries are a critical component of a diesel engine’s starter system. Once they begin to decline, it can cause your diesel engine to have difficulty starting as your compression ratio will be off. As you use the storage batteries, lose their active material depletes over time. Therefore, the likelihood that you need to replace your lead-storage batteries at least once eventually is high.

Fixing Compression Ratio

The average diesel engine has a compression ratio of 20:1, although some can operate at higher ratios. The proper compression ratio in your engine is vital to it running smoothly. If your compression ratio falls below that, it can cause difficulty in steering. If your compression ratio is too high, it can cause engine knock or fuel injection issues.

Replacing Bearings

One commonly overlooked diesel engine problem is when bearings fail. The symptoms involve engine noise or knocking, which can sometimes be mistakenly diagnosed as a fuel injector problem. If your engine is not adequately lubricated, bearings do not get the oil they need and will begin the road towards bearing failure. Failed bearings will show uneven wear patterns and will lead towards even more significant, more expensive problems with your diesel engine.

Correcting Oil Weight Viscosity

It is easy to get the viscosity weight wrong when replacing oil. Mechanics see this a lot when troubleshooting a diesel engine that is hard starting. It is quite easy to forget to change your oil weight viscosity during the changes in the seasons. Single-weight engine oil is better served in a warmer climate, while a multi-viscosity oil should be used in colder temperatures. 

Replacing Oxidized Oil

If your diesel engine sits for an extended period of time without being turned on or driven, the oil will begin to oxidize, creating air bubbles that can wreak havoc on an engine. Our technicians see a lot of fleet operators who have had a truck on the lot for extended periods that need to have the oil changed out. High humidity can also cause oxidation. No matter what the cause, oxidation will cause your engine oil to lose its effectiveness and possibly damage your engine’s components.

Certified Diesel Solutions in Knoxville, TN

One thing you might have noticed is that many common problems with diesel engines are often attributed to the same or similar symptoms. Because it can be complicated to locate the source of the problem, you should have an ASE certified diesel technician diagnose and repair the problems when they occur. By trusting the advice of an experienced diesel mechanic, you will be saving time and money. Certified Diesel Solutions provide fleet, maintenance, and repair services for both diesel and gasoline engines in Knoxville, TN. We are committed to keeping your vehicle on the road and in good working order. Contact us online or by calling (865) 964-6598 to make an appointment for a repair or preventative maintenance visit.