Why 6.7 Powerstroke Whine When Accelerating? (Fix Now)

Powerstroke 6.7 engine is mostly used in Ford F250 vehicles. It is a very reliable engine that offers long-distance durability. But one problem that users face is a whining sound whenever they try to accelerate. 

The most common causes of whining during acceleration of the 6.7 Powerstroke engine are a failing or faulty alternator or a shortage of power steering fluid. You may also notice other factors such as a failing water pump or a worn-out serpentine belt.  

In this article, we’ll go through five common causes and their relevant solutions for the identified causes. 

Why 6.7 Powerstroke Whine When Accelerating

Why Does My 6.7 Powerstroke Whine When Accelerating?

The most common causes of whining during acceleration of the 6.7 horsepower engine are a failing alternator or low power steering fluid. But there might be other factors as well, which include: 

  • Failing alternator 
  • Low Power Steering Fluid 
  • Failing Water Pump 
  • Worn out Serpentine belt 
  • Bad timing belt tensioner

5 Possible Solutions of 6.7 Powerstroke Whine When Accelerating  

We mentioned the most common causes, such as a failing alternator or power steering fluid, but here we go into how we can fix these issues as well as the cost associated with the solutions.  

1. Faulty alternator: Purchase a new alternator

A failing or dead alternator is one of the most common causes of a whining sound during acceleration of a 6.7 Powerstroke engine. Signs of failing Alternator problems include abnormally illuminated lights, slow functioning car accessories, battery warning lights, etc. 

The solution is to simply get a new alternator. Take the following course of action to replace the alternator:  

  1. Start by getting the appropriate equipment for the repair. Make sure to get the right replacement kit for the alternator model that you have in your 6.7 Powerstroke driven vehicle. 
  2. Disconnect the positive terminal of the battery for safety reasons. 
  3. The next step is to remove the alternator. First remove the harness on the back of the alternator. Fill the reservoir with steering fluid. and then proceed to remove the two bolts keeping the alternator attached. 
  4. Remove the plastic cover of the alternator by detaching the two bolts on it. 
  5. Now remove the brushes and the regulator. Then proceed by installing the new regulator followed by the new brushes. Make sure to have the bolts tightened and the wiring done correctly. 
  6. Continue by refitting the plastic cover, followed by the alternator. 
  7. Check if the new alternator works by connecting it to a multimeter and starting the car. If you register a reading of around +14.3 volts, then you’ll know that it is working. 

Changing the alternator will cost you between $120 and $260. 

2. Low Power Steering fluid: Fill the reservoir with steering fluid.  

To check whether the cause of the whining sound on the 6.7 Powerstroke is the power steering, turn the steering wheel in both directions. If you notice that the sound of the whine increases as you steer, then you are low on steering fluid. 

Follow these steps to fill up the reservoir with steering fluid. 

  1. First, you have to find the reservoir cylinder holding the power steering fluid. You will usually find it in the owner’s manual. 
  2. Using the dipstick attached to the cap, check the level of power steering fluid. 

Make sure to take out the dipstick and then wipe it dry before reinserting it into the cylinder to get a more accurate estimate. 

  1. Examine the fluid-covered portion of the dipstick 
  2. Check the color of the fluid to see if it is clear or pinkish. That means the fluid is of good quality. 
  3. Now add the required amount of fluid as needed. If the dipstick has gradations, use that to ensure accuracy of fluid amount. 
  4. Finish by firmly locking the cap in place. 

The power steering fluid will cost no more than $10–$12 per bottle. 

3. Failing water pump: replace the water pump. 

A water pump failure will usually result in a squeaking sound that’s higher than in the case of a faulty alternator. Common signs of a failing water pump are an overheating engine (signified by warning lights) and coolant leakage. 

To replace the water pump, follow the given procedure below. 

  1. First, wait until the engine is cool to ensure safety. 
  2. Take out all the belt drive components by adhering to the manufacturer’s recommended steps. 
  3. Disconnect the hose from the water pump. Put a bucket under the pump as some of the coolant liquid will fall off as well. 
  4. Unbolt the water pump and then remove it. 
  5. Remove any remaining sealant from the pump. Also, make sure that the mounting surface is not dirty. 
  6. Check the other parts of the coolant system, such as the thermostat, coolant hose, etc., before putting in a new water pump. 
  7. Now it is time to install the new water pump. Make sure to adhere to the replacement requirements. If this is the case, a replacement is required. 

4. Worn Serpentine Belt: Replace The Serpentine Belt 

The most clear sign that the serpentine belt is worn out is when there are warning signs that flash on the dashboard of the 6.7 Powerstroke engine vehicle. 

Heavy steering, high pitched sounds, non-functional air conditioner etc. are other common signs of the problem. The solution for a worn serpentine belt is to get a new one. The following steps will guide you through it. 

  1. Start by locating the serpentine belt. You will find it inside the hood of the vehicle.
  2. Make sure to keep the battery disconnected to ensure maximum safety. 
  3. Determine whether the belt is being pressed by an auto tensioner or a movable bracket.
    • In the case of an auto tensioner, you will need a wrench to get it off. 
    • In the case of a bracket, you will have to unbolt it. Usually, there would be 2 bolts keeping the belt in place. 
  4. Once you relieve the tension on the belt, pull it apart. 
  5. Now it’s time to install a new tensioner belt. Compare the new and old ones so that the size matches and that the new one is not damaged. 
  6. Run the belt through the pulleys the same way the old one was. 
  7. Use the auto tensioner/bracket to put pressure on the belt to keep it in   place. Follow these steps. 

A new serpentine belt will cost you no more than $30 to $70. But the labor costs will add another $50-100 getting it around the $150-170 range. .

5. Bad Timing Belt Tensioner: Replace the Timing Belt Tensioner 

If your belt tensioner is at fault, you will find that the check engine is lighting up. You may also hear grinding or knocking sounds, or the engine falling over. 

To replace the belt tensioner, follow these steps. 

  1. Remove the belt by having the tensioner rotated.
  2. Proceed by removing the tensioner. 3. 
  3. After that, install the new tensioner. 
  4. Using a star bit screwdriver, tighten the mounting bolts to 13 of the installation torque. 
  5. Retighten it to 23% of its original torque before completing the full torque. 
  6. Inspect the drive system for any damage. 
  7. Load the belt by re-rotating the tensioner in reverse to what you did in advance. 

The cost of getting a new timing belt tensioner for the 6.7 Powerstroke can go from $50 to $360 if only parts are considered. The cost of labor can add another $50 to $150. 

Frequently Asked Questions

Users of the Ford vehicles that run on the 6.7 Powerstroke engine have a lot of questions regarding this issue of the engine whining when you accelerate. The questions asked most frequently are given here. 

Why Does My 6.7 Powerstroke Engine Vehicle Whine When I Accelerate? 

There are numerous reasons for this happening. The most common cause is a faulty alternator. You should also check the steering reservoir to see whether you have enough steering fluid. 
Other reasons include a worn out serpentine belt or a failing water pump. 

What Should I Do If I Have A Bad Alternator On My 6.7 Powerstroke Engine Vehicle? 

If the reason for the whining noise on the 6.7 Powerstroke vehicle when accelerating is a bad alternator, then you need to get it replaced. The cost of a new alternator varies between $120 and $260. 

What Should I Do If The Water Pump Is Damaged? 

Again, if the water pump is damaged or broken, you have no choice but to replace it. The cost of a new water pump is usually not more than $70 at max, but the labor costs will take it up to $400 at max. 

How Serious It Is If A Worn Out Serpentine Belt Is The Cause Of Whining During Acceleration?

For the 6.7 Powerstroke, it is more of a mild annoyance rather than a severe problem, as the problem can be fixed quite easily by changing the serpentine belt. 


The 6.7 Powerstroke engine making a whining sound as you put on the acceleration is not an uncommon issue.

As annoying as the problem might be, it is not unfixable, as we discussed here. So you have nothing to fear.

Happy riding..

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