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You’re driving your 5.9 Cummins diesel truck, enjoying the power and reliability of your engine. Suddenly, you notice your oil pressure gauge dropping to zero. You panic. What’s going on? Is your engine damaged? Do you need to replace it?
Before you freak out, you should know that there is a reason behind these issues: the oil pressure relief valve. This small but vital component regulates the oil pressure in your engine and prevents it from getting too high or too low. However, over time, it can wear out, get stuck, or crack, causing oil leaks and pressure and problems.
In this blog post, we will explain everything you need to know about the oil pressure relief valve: what it is, where it is located, and how to replace it. By following our simple guide, you will be able to fix your oil pressure issues and extend the life of your engine. Let’s get started!
What Is The Oil Pressure Relief Valve?
The oil pressure relief valve is a device that controls the oil pressure in the engine. It is designed to open when the oil pressure exceeds a certain value and to close when the oil pressure drops below that value. The purpose of the oil pressure relief valve is to protect the engine and the oil filter from damage due to excessive oil pressure.
The oil pressure relief valve consists of a spring-loaded plunger that moves inside a housing. The plunger has a hole that allows oil to flow through it when the valve is open. The spring pushes the plunger against the oil pressure, and the oil pressure pushes the plunger against the spring. The balance between these two forces determines the opening and closing of the valve.
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What Causes The Oil Pressure Relief Valve To Fail?
There are several possible causes of oil pressure relief valve failure, such as:
- Wear and tear due to age or mileage
- Dirt or debris clogging the valve or the oil passages
- Incorrect oil viscosity or quality
- Excessive oil pressure due to a faulty oil pump or a blocked oil filter
Where Is The 5.9 Cummins Oil Pressure Relief valve located?
The oil pressure relief valve in a 5.9 Cummins engine is located at the oil pump outlet. It is attached to the oil filter housing by a large bolt. The oil pump is located at the front of the engine, below the injection pump. To access the oil pressure relief valve, you will need to remove the oil filter and the oil filter housing.
How Do I Test The Oil Pressure Relief Valve?
One way to test the oil pressure relief valve is to use a mechanical oil pressure gauge. You will need to disconnect the electrical oil pressure sensor and connect the gauge to the oil pressure port. Then, start the engine and observe the oil pressure readings at different RPMs. Compare the readings to the specifications in your owner’s manual or service manual. If the oil pressure is too high or too low, or if it fluctuates erratically, the oil pressure relief valve may be faulty.
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How To Replace The Oil Pressure Relief Valve?
To replace the oil pressure relief valve, you will need the following tools and parts:
- A new oil pressure relief valve
- A new oil filter
- A new oil filter housing gasket
- A socket wrench
- A torque wrench
- A drain pan
- A rag
After you have gotten all the required tools, the steps to replace the oil pressure relief valve are as follows:
Step 1. Park your vehicle on a level surface and turn off the engine. Wait for the engine to cool down completely.
Step 2. Locate the oil drain plug under the engine and place a drain pan under it. Remove the oil drain plug and let the oil drain out completely. Replace the oil drain plug and tighten it securely.
Step 3. Locate the oil filter and the oil filter housing on the front of the engine. Remove the oil filter by unscrewing it counterclockwise. Discard the old oil filter and wipe off any oil residue from the oil filter housing.
Step 4. Locate the oil pressure relief valve bolt on the bottom of the oil filter housing. It is a large bolt with a hexagonal head. Use a socket wrench to loosen the bolt and remove it. Be careful not to drop the bolt or the oil pressure relief valve assembly.
Step 5. Pull out the oil pressure relief valve assembly from the oil filter housing. It consists of a housing, a spring, and a plunger. Inspect the assembly for any signs of wear or damage. If the plunger is stuck, the spring is broken, or the housing is cracked, you will need to replace the entire assembly.
Step 6. Install the new oil pressure relief valve assembly into the oil filter housing. Make sure the plunger is facing the oil pump and the spring is facing the oil filter. Align the bolt hole on the housing with the bolt hole on the oil filter housing. Insert the bolt and tighten it with a torque wrench to the specified torque value. Refer to your owner’s manual or service manual for the correct torque value.
Step 7. Install the new oil filter housing gasket on the oil filter housing. Make sure the gasket is properly seated and aligned with the oil filter housing.
Step 8. Install the new oil filter on the oil filter housing. Screw it clockwise until it is snug. Do not over-tighten the oil filter.
Step 9. Lastly, check the oil level on the dipstick and add oil if necessary. Start the engine and let it run for a few minutes. Check for any oil leaks or abnormal noises. Turn off the engine and check the oil level again. Adjust the oil level if needed.
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How Much Does It Cost To Replace The Oil Pressure Relief Valve?
The cost of replacing the oil pressure relief valve depends on the make and model of your vehicle, the labor rate of your mechanic, and the price of the parts.
The average cost of replacing the oil pressure relief valve ranges from $80 to $300. However, you can save money by doing it yourself, as the parts are relatively cheap and the procedure is not very complicated. You can find the oil pressure relief valve, the oil filter, and the oil filter housing gasket for your 5.9 Cummins engine.
Final Words
The oil pressure relief valve is a crucial component of your 5.9 Cummins engine. It regulates the oil pressure and protects your engine from damage. However, it can also cause problems if it malfunctions or fails. Low oil pressure, oil leaks, and engine noise are some of the symptoms of a bad oil pressure relief valve.
Fortunately, you can easily replace the oil pressure relief valve yourself by following our simple guide. You will need some basic tools and parts and about an hour of your time. By replacing the oil pressure relief valve, you will restore the optimal oil pressure and extend the life of your engine. If you have any questions or feedback, please leave a comment below.
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