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Oil pressure is an important indicator of the health and performance of your engine. It measures the force that the oil exerts on the walls of the oil passages as it circulates through the engine.
A normal oil pressure reading should be between 20 and 60 psi, depending on the engine speed, temperature, and oil viscosity.
However, sometimes you may notice that your oil pressure gauge drops to zero and then goes back up, either intermittently or frequently.
This can be alarming and confusing, as it may indicate a serious problem with your engine or just a faulty sensor.
In this blog post, we will explain the possible causes and solutions for this issue and how to prevent it from happening again.
Possible Causes of Oil Pressure Gauge Drops to Zero Then Goes Back Up
Several factors can cause your oil pressure gauge to drop to zero and then go back up, such as:
1. A Bad Oil Pressure Sensor or Sending Unit
The oil pressure sensor or sending unit is a device that monitors the oil pressure and sends the signal to the gauge or the warning light.
If the sensor or the sending unit is faulty, it may send inaccurate or erratic readings, causing the gauge to drop to zero and then go back up.
This is one of the most common and easiest causes to fix, as you just need to replace the sensor or the sending unit with a new one.
2. A Clogged or Restricted Oil Filter or Oil Passages
The oil filter and the oil passages are responsible for filtering and delivering the oil to the engine components.
If the oil filter or the oil passages are clogged or restricted by dirt, sludge, or debris, the oil flow and pressure will be reduced, causing the gauge to drop to zero and then go back up.
This can also damage the engine by causing excessive wear and tear, overheating, and knocking.
To fix this, you need to change the oil filter and flush the oil passages with a suitable cleaner.
3. A Worn or Damaged Oil Pump
The oil pump is the device that pumps the oil from the oil pan to the engine.
If the oil pump is worn or damaged, it may not be able to generate enough oil pressure, causing the gauge to drop to zero and then go back up.
This can also starve the engine of oil and cause severe damage. To fix this, you need to replace the oil pump with a new one.
4. A Low Oil Level or a Wrong Oil Viscosity
The oil level and the oil viscosity are also important factors that affect the oil pressure.
If the oil level is too low, there may not be enough oil to circulate through the engine, causing the gauge to drop to zero and then go back up.
If the oil viscosity is too high or too low, it may not flow properly or lubricate the engine adequately, causing the same issue.
To fix this, you need to check and adjust the oil level and the oil viscosity according to the manufacturer’s specifications.
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How to Diagnose and Fix the Oil Pressure Gauge Drops to Zero Then Goes Back Up Issue
If you notice that your oil pressure gauge drops to zero and then goes back up, you should not ignore it or drive your vehicle until you find out the cause and fix it.
Driving with low or no oil pressure can cause irreversible damage to your engine and cost you a lot of money in repairs or replacements. Here are some steps that you can follow to diagnose and fix the issue:
Step 1: Check the oil level and the oil condition.
The first thing that you should do is check the oil level and the oil condition using the dipstick.
Make sure that the engine is off and cool and that the vehicle is parked on a level surface.
Pull out the dipstick, wipe it clean, and insert it back into the oil pan. Pull it out again and check the oil level and the oil condition.
The oil level should be between the minimum and maximum marks on the dipstick, and the oil condition should be clean and clear.
If the oil level is too low, add more oil until it reaches the proper level. If the oil condition is dirty, dark, or milky, change the oil and the oil filter as soon as possible.
Step 2: Check the oil pressure sensor or sending unit.
The next thing that you should do is check the oil pressure sensor or sending unit for any signs of damage, corrosion, or loose connections.
The oil pressure sensor or sending unit is usually located near the oil filter or the oil pan, depending on the vehicle model.
You can use a multimeter or a test light to check the voltage and resistance of the sensor or the sending unit and compare them with the specifications in the service manual. If the sensor or the sending unit is faulty, replace it with a new one.
Step 3: Check the oil pressure with a mechanical gauge.
The final thing that you should do is check the oil pressure with a mechanical gauge to confirm the accuracy of the oil pressure gauge.
A mechanical gauge is a device that measures the actual oil pressure in the engine, and it can be attached to the oil pressure sensor or sending unit port.
You can buy a mechanical gauge from an auto parts store or rent one from a tool rental shop. Follow the instructions on the gauge kit to install and use the mechanical gauge, and compare the readings with the specifications in the service manual.
If the oil pressure is within the normal range, the oil pressure gauge is faulty and needs to be replaced.
If the oil pressure is too low or too high, there is a problem with the oil pump, the oil filter, or the oil passages, and they need to be inspected and repaired.
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How to Prevent the Oil Pressure Gauge Drops to Zero Then Goes Back Up Issue
The best way to prevent the oil pressure gauge from dropping to zero and then going back up is to maintain your engine and your oil system regularly and properly. Here are some tips that you can follow to prevent the issue:
1. Change the oil and the oil filter regularly.
Changing the oil and the oil filter regularly is one of the most important and easiest ways to prevent the issue.
The oil and the oil filter are responsible for lubricating, cooling, and cleaning the engine, and they need to be replaced at the recommended intervals or sooner, depending on the driving conditions and the oil quality.
You can check the owner’s manual or the service manual for the recommended oil type, viscosity, and change intervals for your vehicle.
You can also use synthetic oil or an oil additive to improve the oil’s performance and protection.
2. Check the oil level and the oil condition frequently.
Checking the oil level and the oil condition frequently is another important and easy way to prevent the issue.
The oil level and the oil condition can affect the oil pressure and the engine performance, and they need to be monitored and adjusted regularly.
You can use the dipstick to check the oil level and condition every time you fill up the gas tank, or at least once a month.
If the oil level is too low, add more oil until it reaches the proper level. If the oil condition is dirty, dark, or milky, change the oil and the oil filter as soon as possible.
3. Inspect the oil pressure sensor or sending unit periodically.
Inspecting the oil pressure sensor or sending the unit periodically is another important and easy way to prevent the issue.
The oil pressure sensor or sending unit is the device that monitors the oil pressure and sends the signal to the gauge or the warning light, and it can fail or malfunction over time.
You can use a multimeter or a test light to check the voltage and resistance of the sensor or the sending unit and compare them with the specifications in the service manual. If the sensor or the sending unit is faulty, replace it with a new one.
4. Inspect the oil pump, the oil filter, and the oil passages occasionally.
Inspecting the oil pump, the oil filter, and the oil passages occasionally is another important and not-so-easy way to prevent the issue.
The oil pump, the oil filter, and the oil passages are the components that pump, filter, and deliver the oil to the engine, and they can wear out or get clogged over time.
You can use a mechanical gauge to check the oil pressure in the engine and compare it with the specifications in the service manual.
If the oil pressure is too low or too high, there is a problem with the oil pump, the oil filter, or the oil passages, and they need to be inspected and repaired.
Final Words
The oil pressure gauge dropping to zero and then going back up is a common and potentially serious issue that can affect your engine and your vehicle. It can be caused by a bad oil pressure sensor or sending unit, a clogged or restricted oil filter or oil passages, a worn or damaged oil pump, a low oil level or the wrong oil viscosity, or a faulty oil pressure gauge. You can diagnose and fix the issue by following the recommended steps outlined in this blog post.
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