Common Mack E7 Engine Problems – Is This Engine Worth It?

You may be wondering about some Mack E7 problems and whether it is a good value for your money.

When you are driving a semi truck, you want to make sure that your engine is highly capable of the tasks at hand. After all, you would not want to end up getting stuck on the road.

You depend on your truck for carrying heavy loads and over long distances. This is why it is only right that the engine is sturdy, durable, resilient, and long-lasting. 

So, if you are thinking about getting a Mack E7, it is good to know what you can expect from it and if it is worth a purchase. Let’s learn more about this engine and what you should know about it.

mack e7 engine problems

Mack E7 Engine Problems

There are instances when problems with your Mack E7 engine will arise. This is why it is best to take notice of certain symptoms, so you can get these addressed sooner than later. Here they are:

1. Changing colors of exhaust

Pay close attention to the colors of your exhaust as this tells a lot about your engine’s condition. For instance, black or blue exhaust means there are oil issues happening since the normal color is gray or white.

Moreover, if you start noticing a darker color of exhaust, it could mean an issue with your piston rings, cylinder liner, or injectors. So, you would need to get your engine checked to have the problem fixed correctly.

2. Odd noises

It is normal for a semi truck engine to make noises when running. However, you should observe the sound you hear since a loud and constant knocking noise is most certainly not normal. It could mean that there is a wear and tear issue with your engine component, or there may also be a combustion timing problem or oil contamination issue happening.

3. Engine performance changes

Another sign that there are problems with your engine is when you notice some changes in the way your engine is performing. Perhaps, your truck is not performing as well as it used to, or the speed has noticeably decreased, then you need to check carefully what may be causing these issues. There may be a problem with some of your engine components that need to be addressed.

Moreover, you may want to check the engine brake and be sure there is no problem with it. When there are issues with this component, it can be quite dangerous to continue driving. More often than not, this issue is due to a cylinder compression loss or a concern with your head gasket, valves, or piston rings.

4. Fuel economy loss

If you have been topping up your fuel more often, then it means that the engine has become less efficient. As an example, you may have worn out or damaged injectors, which is why you are experiencing a loss in fuel economy. 

It is important to pay close attention to any changes or variations in the gas mileage. This is a good way to determine problems with your semi truck and to catch these issues early on before things get worse.

5. Oil level gets low fast

In addition to a reduced fuel economy, you may be experiencing the need to top up on engine oil more frequently. If so, then it is possible that there is an oil leak that needs to be addressed. Sometimes, this problem can also be linked to problems with your cylinder liners and piston rings that need to get checked.

Other Problems With the Mack E7 Engine

mack e7 engine problems

Aside from the issues mentioned above, there are those who may notice that the engine is simply not running as efficiently as it used to. For instance, when you give the engine a throttle and reach 1500 RPM, you may start noticing white smoke getting blown out, in addition to some sputtering sounds.

It may leave you wondering why this happens when your injectors and pump are brand new and the mileage is not too high. 

If this is the issue you are noticing, then it is possible that you have a timing issue. You may also want to check the overflow valve.

When checking the timing, you first need to take out the plug located near your throttle shaft. Then turn your engine to the timing set point, and you should find a component that appears as a slot head screwdriver. If you don’t find this part, then it could be that it has slipped the timing on your pump hub. Just torque it to 225 foot pounds.

When you experience issues with uneven firing, then you may want to inspect the fuel lines. Check if the lines are in good condition and not worn or damaged. Sometimes, debris can also cause issues, which is why you should inspect these components carefully.

Read More: Mack Mdrive Transmission Problems That May Surprise You!

Bottom Line

The Mack E7 engine is generally reliable and has been considered as a workhorse in various industrial applications. However, it is most certainly not made for speed unlike the Detroit, CAT, or Cummins. On the other hand, you can count on its durability and long lifespan. This is why this engine is used for various service applications such as fire engines, refuse vehicles, public bus fleets, and so on. 

It is generally a heavy duty engine, which is also a 6-cylinder. You can use it off-highway or on-highway and numerous industrial applications. 

Yet, if you encounter problems with it, then you should consider getting some key components inspected thoroughly by your mechanic. This way, you should be able to determine the actual cause of the problem and get it remedied appropriately before things take a turn to the worst.

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