Can you drive with a broken oil pressure sending unit?

Quick Answer

It is generally not recommended to drive with a broken oil pressure sending unit. The oil pressure sending unit is a key component that monitors oil pressure in the engine. Driving with a faulty unit can lead to severe engine damage from insufficient oil pressure. However, in some cases it may be possible to drive short distances to a repair shop. Proceed with extreme caution and monitor the engine temperature gauge closely. Have the sending unit replaced as soon as possible.

What is the Oil Pressure Sending Unit?

The oil pressure sending unit, also known as an oil pressure sensor, is an electronic component that monitors oil pressure in the engine. It is typically located near the oil filter or oil pan. The sending unit works by detecting the oil pressure in the engine and sending an electrical signal to the oil pressure gauge on the dashboard. This allows the driver to monitor real-time oil pressure.

The sending unit has an internal diaphragm or switch that actuates when oil pressure reaches a preset level. As oil pressure increases or decreases, the diaphragm flexes, which changes the electrical resistance. This resistance signal is transmitted to the gauge. If oil pressure falls below the operating range, it will trigger the gauge light to illuminate, alerting the driver of a potential issue.

Key Functions of the Oil Pressure Sending Unit:

• Monitors engine oil pressure in real-time
• Sends oil pressure readings to the gauge on the dashboard
• Warns driver if oil pressure falls below safe levels
• Prevents engine damage from oil starvation

The oil pressure sending unit is a vital engine management component. It provides constant feedback about oil circulation to ensure all engine parts remain properly lubricated.

Dangers of Driving with a Faulty Sending Unit

Driving with a malfunctioning or broken oil pressure sending unit can potentially lead to catastrophic engine failure. Here are some key risks:

Inaccurate Oil Pressure Readings

With the sending unit damaged, the oil pressure gauge will provide incorrect or erratic readings. It may show normal pressure even if the actual oil pressure is dangerously low. This lack of proper monitoring can lead to severe issues.

Oil Starvation

If oil pressure drops too low, vital engine components like bearings, cylinders and valves may not receive adequate lubrication. This oil starvation can quickly lead to overheating and friction, causing extensive wear and tear.

Seized Engine

As parts grind without proper oil flow, metal components can weld together. This can seize the engine and lead to a complete loss of power. Driving with a seized motor can also cause extensive damage to other drivetrain components.

Catastrophic Engine Failure

Insufficient oil circulation will eventually overheat internal components and lead to catastrophic failure. Uncontrolled overheating can cause bearings to melt, pistons to warp or crack, and metal parts to expand to the point of self-destruction. Total engine failure often requires expensive repairs or a full replacement.

Warning Signs of a Failing Sending Unit

Some common signs that indicate a faulty oil pressure sending unit include:

• Oil pressure warning light remains on
• Gauge shows no oil pressure reading
• Oil pressure reading fluctuates or is erratic
• Low engine oil level
• Knocking or clattering engine noise
• Oil leaking around the sending unit
• Gauge reads very high pressure all the time

If any of these symptoms arise, it likely indicates the sending unit is malfunctioning. Schedule service immediately to avoid driving with a damaged unit.

Is it Safe to Drive with a Broken Sending Unit?

Driving any significant distance with a confirmed broken oil pressure sending unit is generally unsafe. However, the risks depend somewhat on the nature of the problem:

Sending Unit Completely Unplugged

Driving with the unit completely disconnected is extremely dangerous since the gauge will display normal readings even with no oil pressure. This provides zero protection from oil starvation. Only drive to the nearest shop if absolutely necessary.

Intermittent Electrical Failure

If the sending unit has an internal electrical issue causing intermittent signal loss, the gauge may still provide some relevant pressure feedback. Very short drives may be possible but still risky.

External Oil Leak

If oil leaks only around the sending unit seal, damage is less likely. Some minor driving could be safe as long as oil level is confirmed adequate. Monitor the gauge closely and be prepared to shut off the engine immediately if readings drop or waver.

Display Reads Zero Pressure

If the gauge reads zero pressure, the unit has likely failed completely. Do not drive the vehicle as overheating can occur rapidly. Call for a tow truck. Even idling the engine for long with zero indicated pressure can lead to significant wear.

Precautions for Driving with Sending Unit Issues

Avoid driving with a faulty sending unit whenever possible. But if you must drive a short distance, such as to a repair shop, take extreme precautions:

• Check engine oil level before driving. Top off if low.
• Watch the temperature gauge closely for any signs of overheating.
• Drive slowly and avoid high RPMs or loads. No highway driving.
• Stop immediately if oil light activates or temperature rises.
• Pull over and shut off engine if gauge readings drop or fluctuate.
• Be prepared to add oil if needed. Keep extra engine oil on hand.
• Consider having the vehicle towed instead.

Even a few miles of driving with a malfunctioning sending unit can result in serious damage. Use all precautions and have it repaired as soon as possible.

Diagnosing a Faulty Sending Unit

Some steps to properly diagnose a potential sending unit problem:

• Check engine oil level and quality. Fill or change oil if needed.
• Inspect wiring to sending unit for damage. Replace connectors if corroded.
• Monitor gauge during engine running and look for erratic readings.
• Use an oil pressure test kit to verify actual system pressure.
• Perform voltage drop test on sending unit circuit.
• Disconnect electrical connector and check for signal with a multimeter.
• Replace sending unit if malfunction is confirmed.

Verifying if the sending unit itself has failed, versus an electrical issue or actual low oil pressure, helps avoid unnecessary replacement costs. Consult a professional auto technician for testing if needed.

Replacing a Failed Sending Unit

Here are some tips for replacing a failed oil pressure sending unit:

• Locate the sending unit, usually near oil filter.
• Disconnect electrical connector from sending unit.
• Use appropriate socket to unscrew sending unit.
• Apply sealant to new sending unit threads if needed.
• Screw in new unit and tighten to specification.
• Reconnect electrical connector.
• Start engine and check for leaks.
• Confirm new unit displays proper oil pressure readings.

Take care not to damage sensor threads or electrical connector during removal. Make sure to use proper torque when reinstalling. Most sending units can be easily replaced in under 30 minutes if you have the right tools.

Conclusion

Driving with a broken oil pressure sending unit is never recommended. This vital component warns the driver of low oil pressure to prevent catastrophic engine damage from insufficient lubrication. However, carefully driving extremely short distances to a repair shop may be possible if oil level is adequate. Use extreme caution, monitor the temperature gauge closely, drive slowly, and watch for warning lights. Schedule sending unit replacement or repair as soon as possible to avoid driving in a risky condition. With proper precautions and diagnosis, a faulty sending unit can be fixed before leading to major issues.

Sending Unit Condition	Driving Risk
Completely unplugged	Extremely dangerous. Do not drive.
Intermittent electrical failure	Very risky but short distances may be possible.
External oil leak only	Low risk for short drives if oil level verified.
Reads zero pressure	Do not drive at all.

Key Steps to Replace Failed Sending Unit:

1. Locate sending unit near oil filter.
2. Disconnect electrical connector.
3. Unscrew bad sending unit.
4. Apply sealant to new unit threads if needed.
5. Screw in and tighten replacement to specification.
6. Reconnect electrical connector.
7. Check for leaks and test gauge operation.