3 Symptoms of a Seized Engine (and What Causes It to Lock Up)

An engine seizing up can destroy components (and derail your day). But what causes it and is repair even possible?

Learn the symptoms of an engine that’s seizing up so you can spot problems quickly and potentially save your engine from terminal damage.

Locked Up Engine vs Seized Engine

While these two terms are often used interchangeably, they do actually mean two different things. While they may cause the some of the same symptoms, repair costs can be quite different.

A locked up engine is when something is physically preventing the engine from turning, such as a broken or bent component. Although it may not rotate at the moment, the engine can be fixed and made operational again.

On the other hand, a seized engine occurs when the internal components suffer significant damage, such as bearings fusing with the crankshaft or pistons seizing within the cylinders. Typically, a seized engine results from overheating or lack of lubrication, and it’s harder and often more expensive to repair compared to a locked engine.

Seized Engine Symptoms

Fortunately, a seizing engine will not mean it is already destroyed. There are some symptoms that you should recognize as early warning signs.

If you can spot them early on, you may have time to take your vehicle to a repair shop and have them fix the problem before it causes worse problems for the engine.

Below are the top 3 symptoms of a car engine seizing up.

#1 – Oil Light On

low oil pressure warning light on

If your engine components are locking up, it will hinder the circulation of oil. Your engine control unit will immediately detect something is wrong with the oil flow once this happens.

In response, the unit will activate engine oil warning light on the dashboard. Some vehicles share this warning light with the “Check Engine” light, so you may have either or both lights come on.

#2 – Poor Acceleration (or None At All)

car shuts off while driving

You cannot have a seizing engine and still be able to drive your vehicle normally. When your engine begins to seize, you can expect its performance to diminish, often greatly.

This means that each time you step on the gas pedal to accelerate your vehicle, you are probably not going to go as fast as you normally would. In fact, you may not be able to pick up speed at all.

It will eventually get to the point where your engine is locked up to the point where your car will just stop for good.

#3 – Knocking Sounds

rattling noise

During a seizing engine situation, the piston rod knocks against the crankshaft. This will happen repeatedly, causing knocking sounds to be heard. The sounds will continue to become louder and worse unless you address the problem fast.

What Causes a Seized or Locked Up Engine?

Inadequate Lubrication

One of the main reasons for an engine to seize is inadequate lubrication. The engine’s components, such as the pistons, crankshaft, and cylinder walls, rely on a constant supply of oil to minimize friction and prevent excessive heat.

If your engine runs low on oil or if the oil filter is clogged, it can cause the components to grind together, leading to increased friction and eventually causing the engine to seize.

Two of the most important things to do as a car owner are regularly checking your oil level and replacing the oil filter when necessary.

Overheating and Heat Damage

Overheating is another common cause of engine seizure. An engine can overheat for numerous reasons, including a lack of coolant, malfunctioning cooling system, or extreme temperatures.

When an engine overheats, the excessive heat causes the metal components to expand, which can lead to friction and damage to the pistons, piston rings, and cylinder walls. Enough heat and friction can actually cause some components to fuse or weld together. Consequently, this will cause the engine to seize.

Making sure that your cooling system is functioning correctly and maintaining the proper coolant levels can help prevent overheating and engine seizure.

Water and Hydrolocking

Water ingress is another culprit that can cause an engine to seize. When water enters the engine through the air intake or an internal leak, it can cause a condition called hydrolocking. As water cannot be compressed like air and fuel, the presence of water in the cylinders prevents the pistons from moving, leading to a hydrolocked engine.

Unlike vapor lock, which can be resolved by allowing the engine to cool down, hydrolocking can result in major damage to the engine components, such as bent connecting rods or a cracked engine block.

To avoid hydrolocking your engine, be cautious when driving through standing water and inspect your intake valves and seals regularly for any signs of damage or leaks. Additionally, make sure to keep up with routine maintenance, such as changing the spark plugs and performing regular engine inspections.

Can You Fix a Seized Engine?

causes of locked up engine

Once an engine is deemed “seized” by a mechanic, there unfortunately aren’t many options available for the vehicle owner. In the majority of cases, engine replacement will be recommended or necessary simply due to the fact that the internal damage will likely be severe.

While it may be possible to repair damaged components and have the engine block repaired at a machine shop, the cost of rebuilding the engine is typically more than simply replacing it altogether. The exception are would be certain “high-performance” or rare engines (which will be expensive no matter which route you take).

However, there may be instances where the cause of engine lock up is simply due to the vehicle sitting too long and exposed to the elements. In these cases, you may be able to salvage the engine. This is why dealing with a trustworthy mechanic is so important.

Seized Engine vs Bad Starter

This is an important one. Because a bad starter that’s seized up and its solenoid is stuck can share some of the same symptoms as a seized up engine, it’s important to get the diagnose correct.

The mechanic will usually attempt to manually rotate the crankshaft to make sure your starter is not the culprit. If the crankshaft can be rotated, the problem is likely the starter. If not, the starter is then removed and manually rotating the crankshaft is checked again.

How Does a Mechanic Confirm a Seized Engine?

To confirm a seized engine, a mechanic will first check for any external obstructions or damage. If none are found, they may try to manually rotate the engine using a breaker bar or a wrench. If the engine refuses to budge or rotates with extreme difficulty, it’s a strong indication that the engine is seized.

Additionally, a mechanic will check for warning signs like low oil pressure, empty coolant reservoir, or a burning odor. In some cases, they may also perform a compression test or an endoscopy to assess the internal condition of the engine.

Is It Possible for an Engine to Seize With Oil in It?

Yes, an engine can still seize even with oil in it if the lubrication system isn’t functioning properly. For instance, if there’s a blockage in the oil passages or the oil pump is bad, proper lubrication won’t reach critical moving parts, leading to friction, overheating, and ultimately a seized engine.

On top of that, using the wrong type of oil, infrequent oil changes, or running low on oil can also contribute to a seized engine. Regularly checking and maintaining your vehicle’s oil levels and oil quality can help prevent engine seizure.

Mark Stevens

14 Comments

  1. Just got a new engine to replace my old one which done a head gasket. When I bought the new engine everything was working and rotating fine.

    When I finished installing the engine and try to fire it up, all I hear is a click sound, I trying turning the engine manually but is full seized and the engine wasn’t seized before I put it in. The engine hasn’t run at all to to consider the other factors that can cause this to happen.
    can someone please help me it will be much appreciated, thanks.

    1. Can you turn the engine over by hand?

      Recheck your timing. If you have an interference engine and the timing belt is loose or slipped, that could very well prevent the engine from turning over.

  2. I have an old 77 boat with a 302 Ford V8 that I bought and when I got it home I manually cranked it by hand. Also tried the starter and it was turning over fine. Than it stopped turning over and I can’t turn it by hand. Any thoughts ??

    1. I really don’t know anything about boats, but I’m wondering if there’s an issue with the timing chain in that motor. Maybe a weak chain or failed tensioner that broke when you turned the motor with the starter. Have you been able to tear down the engine to assess the situation?

  3. My 2011 Tiguan started failing power steers intermittently 4x over the past 2.5 years since buying it used in 2018. Recently was five days ago; restarting corrects it. Yesterday while driving thought I noted momentary loss of acceleration, but attributed it to imagination. Half an hour later experienced loss of engine power. Waited five minutes and restarted fine but new EPC light was on. I managed to get home with no trouble and on restart EPC light went out so I assumed all was fine. Went out to nearby errand today and it stalled again, only this time would not start again. It cracks but won’t start. Towed it home and charged battery – still nothing. I don’t have a code scanner but am very worried this is something very big I may not be able to afford. It is Sunday and doubtful any shop will have time Monday to get it in. Any ideas what the top issues could be from worst to least? TIA

  4. My 07 Cadillac sts won’t turn over. It just clicks when you try to start it. I was told it’s the motor seized but also was told it might be the starter. Does anyone have any idea?

    1. If you can spin the engine with a ratchet on the crankshaft pulley, your engine isn’t seized. You checked the battery, right? Make sure the battery terminals are clean and free of corrosion. It could also be the starter going out. You’ll have to spend a bit more time with it to narrow it down.

  5. My Honda Vti oriel 2005 prosmatic is heated very hot engine oil smell block is fail head is save water body leak car is ver hot can I block repair or engine change

  6. I had my 2002 Saturn SL1 die on me on a mountain pass, i was matting the throttle to get up the mountain, the oil pressure light came on and a split second later the car died. The car is in a no crank no start situation, when I put the ignition to start I hear a clunk noise. I replaced the battery, I have no low beam lights but do have high beams.

    1. Does the engine turn over by hand? Low oil pressure followed by a dead engine is not a good sign… It sounds like the oil pump may have gone out or the vehicle was starved of oil for some reason. Check the oil to make sure it isn’t low. If the oil level was low, you’re probably looking at an engine replacement.

  7. I tried starting my engine after a wrecker haul it home. A heater hose blew and it was immediately hauled home on a Flatbed Wrecker. Was turning over and even started (briefly) with starting fluid! Due to compression. After searching high and low, I discovered the ignition fuse has been removed! Thoroughly disgusts in my find, I let it SIT near two years.Trying again, as someone wished to buy it….I’ve found it locked up tight. Soaked it down with Deep Creep a few days, No Go! Any ideas would be greatly appreciated! Bruce, in Arizona

    1. Since you said it’s locked up after you started it, I’m wondering if the timing belt snapped. Do not attempt to start the vehicle until you can verify the timing belt’s integrity, especially if it’s an interference engine. An interference engine will usually bend valves if it is cranked when the engine is not timed correctly.

      Next, start with the basics: make sure it has all its fluids, particularly engine oil.

      Do a visual inspection to make sure all intake and vacuum hoses are connected. A major vacuum leak would cause it to run poorly, if at all.

      If it sat for 2 years and still has the original fuel in the tank, that fuel probably isn’t going to burn very well. If the tank is low, add some fresh fuel. If it’s full, consider draining the tank. Old gasoline reeks, so you should know pretty quickly if bad gas is the issue.

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