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

Last Updated on May 8, 2020

The internal combustion engine contains many small metal components which move in harmony with one another. That is why when one of these components wears out or fails, it causes all the other components to be thrown off course.

Looking for a good online repair manual?
Click Here
for the 5 best options.

What’s worse is that the engine will suffer a lot of damage once this happens. You could be driving along one day and have your car engine just seize up out of the blue. This will indicate that one or more of your internal components are locking up and not moving. Because of this, the crankshaft cannot move the bearings.

What Causes a Seized Engine?

So, why does the engine seize like this? Well, it usually comes down to engine components that have either welded together or overheated. The most common components include the piston rings, pistons, and rod bearings.

It is hard to repair these problems after they’ve occurred. You may end up having to replace your entire engine. That, of course, will mean spending thousands of dollars that you probably don’t even have available.

Engine Locked Up 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 the auto mechanic 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 – Check Oil Light

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 the “Check Oil” 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 – Weak Acceleration

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.

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 won’t accelerate and then your car will just stop for good.

Read also: The Average Brake Pad Life in Your Car

#3 – Knocking Sounds

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.



  1. 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

    • 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.


Leave a Comment