Difference Between a Running Tested Engine and An Untested Engine

When an engine fails, most car owners panic about cost. A brand new engine is expensive, and repairs add up fast. So, when you start looking at used car parts, the type of engine you buy matters more than the price tag. This is where the difference between a running tested engine and an untested engine becomes important.

Not all used engines are the same. Engines come from accident-damaged cars, insurance write-offs, or vehicles that stopped running due to other issues. 

All you need is to understand how an engine is checked before you purchase from a car wreckers in Melbourne or any other used car parts store.

What is a Running Tested Engine?

A running tested engine means the engine was started and run before it was removed from the vehicle. This is usually done by reliable car wreckers in Melbourne that have the space and setup to test engines safely.

Wreckers start the engine and let it run long enough to observe its behaviour. They check if the engine starts easily, idles smoothly, and runs without unusual noise. In addition to looking for smoke from the exhaust, warning lights on the dashboard, and signs of overheating as the engine warms up.

Running the engine before removal is important. You know the engine was capable of running under its own power before it was pulled out.

At All Good Parts, engines are tested only when it is safe to do so. The vehicle is checked first, then the engine is started and allowed to run long enough to observe how it behaves. We record the dismantling process and how engines are removed step by step. Videos of real vehicles being dismantled are shared on our YouTube channel so buyers can see how engines are handled before they are stored or sold.

What is an Untested Engine?

An untested engine is one that was not started before removal. This does not automatically mean the engine is faulty. It simply means it could not be run.

This happens when a vehicle with a non-functional engine arrives at wreckers, has severe accident damage, or has electrical issues that make starting unsafe. In these cases, the engine is removed based on visual inspection only.

Several things occur with an untested engine. These include:

• Sound
• Smoke
• No confirmation on idle quality

Wreckers can still check oil condition, look for cracks or leaks, and inspect for impact damage. However, the behaviour under running conditions remains unknown. As a result, untested engines are usually sold at a lower price.

Key Differences Between Running Tested Engine and Untested Engine

1. Risk level

• A running tested engine has already been started and run.
• An untested engine has not been run, so its behaviour is unknown.

2. Performance after installation

• A running tested engine is more likely to work as expected when installed correctly.
• An untested engine may work fine, but there is more uncertainty involved.

3. Price difference

• Running tested engines cost more because time and effort go into testing.
• Untested engines are cheaper because testing was not possible, not because they are always faulty.

4. Buyer decision

• Running tested engines suit owners who want lower risk.
• Untested engines suit budget repairs or situations where some risk is acceptable.

The right choice depends on how the car is used and how much risk the owner is comfortable with.

How Car Wreckers in Melbourne Test Used Engines?

Engine testing is not done with machines and graphs. It is done with experience. Before starting any engine, visual checks are done. Oil condition tells a lot. Milky oil points to coolant issues. Burnt oil suggests overheating. Coolant residue around the head or block raises red flags. Engines showing these signs are not run.

If the engine passes inspection, it is started and monitored. We listen for internal noise, watch how quickly it settles into idle, and observe how it responds as it warms. Smoke colour matters. Blue smoke, white smoke, and black smoke all mean different things. 

Anyone who has worked at a car wrecker in Melbourne yard long enough knows the difference without guessing.

Once tested, engines are drained, sealed, and stored correctly. Open ports are covered to stop contamination. This handling is just as important as the test itself.

Why Engine Matching Is Important?

A good engine can still cause problems if it is the wrong one. Cars often use different engine variants across years, trims, and fuel types. Sensors, wiring looms, mounts, and control units change more often than people expect.

Incorrect matching leads to warning lights, wiring issues, poor performance, or cars that will not pass inspection. That is why proper wreckers always ask for full vehicle details and often the VIN.

Common Mistakes Buyers Make With Used Engines

The most common mistake is focusing only on price. Labour costs do not change if an engine fails. Another mistake is ignoring engine codes or assuming engines are interchangeable because they look similar. Buying from private sellers or unverified sources also increases risk, as engines are rarely tested or matched properly.

A proper used car parts store will explain how the engine was sourced, whether it was tested, how it is matched, and what warranty applies.

Conclusion

Decide how the car is used. Ask whether the engine was running tested or untested. Confirm how matching is done. Ask what checks were carried out and what warranty is included.

If you want clear answers before spending money, speak directly with a team that handles used engines every day. You can contact All Good Parts on (03) 9357 2122 to discuss engine availability, compatibility, and testing details.