how to buy a used engine

When your car engine gets spoiled, buying a second-hand car can be a good idea but not always. So, you think of buying a new engine for your vehicle, but suddenly it comes to your mind that your vehicle is an old model and the new engine will not suit.

The second thing which comes in your mind is to buy a used engine. That is a brilliant idea. But there are certain things which you must consider before buying a used engine. You should check the engine carefully before buying.

How to check car engine condition?

We are here to help you understand the things which you must consider before buying a used engine. 

So without wasting time let’s start.

Note Down VIN Number before go to seller

When you go to the seller to buy a used engine always check the VIN (Vehicle Identification Number, a 17 digit code to identify a specific automobile) and the engine number of the engine. Its benefit is you don’t need to tell the seller different shapes how your engine actually looks like and neither need to bring your heavy metal (engine) to shop. 

If you go to the seller without a VIN number, then there are few possibilities to find the exact engine for your vehicle. But after some hard work, if the seller finds the engine of the same size, then the least chances to fit your vehicle.

To avoid these situations, VIN means Vehicle Identification Number and Engine Number will help you, to find your actual engine which will fit in your vehicle. Now you can bring your used engine for your vehicle to home, but wait doesn’t bring it now without checking proper function.

There are many functions are left for checking, let’s do it step by step.

Always buy Complete Assembled Engine.

Always buy the complete assembled engine from the seller as it is shown in the image, to avoid assembling, which will waste your time and nothing more. If you are not a professional in assembling so never buy disassembled engine by mistake. Because there are various types of parts and components in the engine which has a different model. If you are not a professional this will waste your time and irritate you. It may happen from morning to night to assemble it. So the intelligence is to buy a completed engine.

But the topic does not end here you should check complete sensors, wiring harness, valve covers, charge pipes, fuel rail, and injectors, also check their important functions are working or not, like starter, AC compressor, power steering pump, and alternator. 

Also, ask about the history of the engine, how many kilometers the engine has run, is the engine faced an accident or not when was the last time it has run and many more questions that comes in your mind. These questions will help you to guess the actual condition of the engine. And the important thing to remember does not buy the engine in which standard mileage is below 20000 kilometres per year.

Ask the seller is the engine has long block or short block.

Both the engines are the same in size but there are some differences, which we will tell you.

Short Block Engine.

The Short Block engine is the end of a vehicle’s engine. It is a partially assembled engine that has the cylinder block below the head gasket but above the oil pan. It includes crank, engine block, connecting rods and pistons. This engine has a focus on the bottom and end rotating components.

Long Block Engine

Long Block engine is the complete version of the short block engine that includes valve train, cylinder head, valve covers, crankshaft and cylinder head, and other components. It does not require the fuel system components such as fuel pump, fuel injector, and intake manifold. This is the completely assembled engine.

Comparison Long Block v/s Short Block engine

A short block engine has less price than a long block engine, long block engine has a longer warranty than a short block engine. The long block engine is more reliable than the short block engine because it has more components. And final result come out the long block engine is more powerful than the short block engine because their more components support them to be powerful

So try as much as possible to buy a long block engine but to buy a short block engine is not too bad.  

If you have asked the questions, let’s check it practically. 

Always try to check the used engine in the morning cold weather (it is also known as cold checking), because the engine was at eight or nine hours at rest. Cold investigation can display all hidden problems.

If the engine starts in two or three takes it means that it is in good condition, if do not start more than three trials, do not waste your money on it.

It will take some time on cold checking if the engine throws few white clouds of smoke while starting the engine that’s not a problem. Every used engine suffers from this condition in the beginning.

But if you see the engine is exhausting blue smoke and making unusual loud noises that means the engine is burning the oil. This happens because of improper maintenance, leaking oil and not changing lubricating oil and its filter timely. Burning of oil can harm the engine or burn the internal components of the engine or nearby engine components after overflowing. 

Check properly the engine you are going to buy not consuming excess lubrication oil than normal. If it consumes you will see leakage first, but in case of internal leakage, you cannot find (use Borescope camera to find internal damage). 

Bad quality oil usage, old engine, bad valve cover gasket, and high-pressure oil usage are the reasons which force the engine to consume excess oil.

Check the oil leakage in the engine properly.

The engine is the heart of the vehicle and the engine oil is the blood, just think if your heart not pumping your blood properly what will happen the same thing is with the engine. Avoid the engine if there is a low level of oil. Check the engine carefully under the oil cap after removing it.

To check the oil leakage in the engine, keep your eyes on the dipstick and check the overflow or low level of oil. When you pull out the dipstick and see there is a lot of black carbon in it that means the engine has not passed from good services. Oil Pressure Testing is necessary to check the clearance flow of oil. Check the lower part of the engine, everything has to be dry.

Basic Engine Test

All types of tests are necessary to do and the Basic Engine Test is one of them.

  1. Check for sludge in the oil. If you see sludge outside of your engine it is a problem. Remove the oil cap of the oil pan, turn on the light of your mobile or torch and see inside it. Do not buy the engine if you see the metallic and a silver portion of the engine it is a sign of sludge engine. A good engine will always be covered with lubrication oil.
  2. While performing the cold test with engines try to listen carefully. If you listen to abnormal sounds like two metals are colliding with each other, refuse to buy.
  3. Open the engine hood for checking,
  • Air cleaner clogging.
  • Hoses for leaks
  • Gasket and valves
  • Improper connections of harness connectors, wiring harness, and vacuum hoses.
  • Refuse to buy if you smell like burnt oil.

Make sure the engine getting normal temperature while running not getting over. If your engine is overheating in normal weather that means the coolant system of your engine is damaged and not exhausting the heat. If the needle on the temperature gauge pushes its way towards the red zone it may be a sign of overheating.

Don’t forget to check the exhaust fan and other fans are working properly or not. Improper working of fans can create many problems like overheating.

Unusual vibration in the engine may be harmful to your vehicle. About this, we have already told you in Basic Engine Test this sound can be the collision of metal in your engine and can damage internal parts soon.

If you find some little problem in the engine tells the seller immediately to repair or replace the faulty part.

Check from Borescope Inspection Camera

Borescope camera will help you to detect the internal failure of the engine’s parts and components such as bearings and pistons. 

Are your components clean or not? Is there is excess carbon or not? All you can see on the screen of the Borescope. Put the wire in parts from were light blue light is emitting and it will display internal conditions of components. If you have not this, you can purchase it from the market.

Spark Plug Inspection.

Increasing high voltage and the gap of the bridge between the ground electrodes and the center can spark the fire inside the cylinder. And the secondary purpose of Spark Plug Inspection is helping the heat away from the cylinders.

 If you see red coating in the spark plugs, this is not a problem. But the spark plug gets too hot that is the sign of pre-ignition damage.

Check Compression on your engine.

It will check the condition of your cylinder. If the engine has low compression it causes may be Holes in a piston, worn timing chain which is connected to the crankshaft and camshaft, bad piston rings (due to overheating of the engine).

This test will help you to detect the leakage of pressure from rings, cylinders, and valves.

While checking the compression, your engine pressure should be 100 PSI (Pressure per Square Inch), if it is showing the 10% variation around 100 PSI this is not the issue.

Check the coolant and the other leakages.

If you see the coolant leakage from the radiator tell the seller to remove it and place the new radiator. Because sometimes a broken or cracked radiator can create unwanted serious problems. To avoid these situations refuse to buy or remove.

Tell your sellers, you want to check your engine dry because some of the sellers use automatic transmission fluid and thick oil to conduct the compression test successfully which is temporary.

Now you have completely checked the functions of the used engine. But one thing is still left.

After checking the used engine functions properly fix it in your vehicle and take a test drive which will clear your rest of doubts.

These are some points which will help you to before buying used car engines. We hope you like it.

You Want To Have Your Favorite Car?

We have a big list of modern & classic cars in both used and new categories.