Home » My Car Overheated, and Now It Won’t Start [SOLVED]
My Car Overheated and Now It Wont Start

My Car Overheated, and Now It Won’t Start [SOLVED]

You’ve gotten through the morning routine to get to work. The kids are packed and ready to get dropped off at school. You slip behind the wheel, start the ignition, and nothing happens.

The engine doesn’t even turn over. At best, you get a bit of a clunk.

When your car overheats, it can be a frustrating experience. If you didn’t know that this issue was happening in the engine bay, a sudden seizure could leave you wondering what happened.

My Car Overheated, and Now It Won’t Start!

When a vehicle overheats, it can allow water to get into the engine through cracks or seal gaps that form from the high temperatures. If cold temperatures exist, the water can freeze inside the engine as the vehicle rests, causing the engine to seize.

A car that overheats and won’t start will give you two symptoms. It will either turn over without starting when using the ignition, or it won’t crank at all.

Most of the repairs that can restore functionality to a vehicle in this condition require the help of a licensed and certified specialist.

Until the problem gets fixed, you won’t be driving anywhere with your car or truck. It may need to get towed to the dealership or your trusted local shop.

What Are the Problems That Stopped My Car from Starting?

When a car overheats and stops functioning while driving or won’t restart after sitting, the following issues could be responsible for the problem.

Here is a closer look at what could be happening with your vehicle right now.

1. Blown Head Gasket

When intense heat exists in the engine compartment, it causes the engine block and cylinder head to expand quickly. This issue causes the head gasket to blow, forcing coolant to begin leaking into the combustion room.

Once that situation occurs, the engine will start losing power. If the leak is small, you may not notice a reduction in HP while driving. When it is severe, combustion can stop immediately, causing the vehicle to stall.

If combustion isn’t possible, the engine won’t start.

Coolant loss continues when there’s a blown head gasket that pressure tests don’t detect. That causes the engine to overheat more, eventually causing the radiator to have bubbles form. White smoke coming from the compartment indicates that the gasket requires replacement.

You’ll need to remove the top of the compartment, scrape away the damaged gasket, and replace it with a new one.

Although the final steps are relatively simple, it can take several hours to unbolt the cover on some vehicles.

Most vehicles operate a 50/50 mix for their coolant. When the weather turns cold and fluid is in the block, freezing temperatures can cause the engine to seize. The damage can be severe enough that an entire replacement is necessary.

2. Damaged Piston Rings and Valves

When an engine overheats, the piston valves and risks are at risk of experiencing damage. Since these components are responsible for sealing the cylinders, problems with the transmission can develop.

When the valves and rings don’t work as intended, they allow oil leaks to occur. If you smell oil burning while driving, this issue probably exists. It can be diagnosed by performing a compression test.

The OTC 5605 Deluxe Compression Tester Kit can help you determine if there is an issue. It comes with a 25-inch flexible hose gauge and an easy-to-use coupler that gives you a clear view of your readings, even if the bay is cluttered or uses a recessed plug well.

If you have bad valves and rings, they’ll need to be replaced with new ones. Although the parts are affordable, professional labor costs can be quite high.

3. Malfunctioning Thermostat

When your vehicle’s thermostat malfunctions or receives damage, the incorrect readings can impact how other components function.

You might notice that your engine shows a higher temperature than normal while driving. If you see this problem, it’s important to check if the thermostat is functioning correctly as soon as possible.

It is much cheaper to replace a malfunctioning or damaged thermostat than it is to repair an engine block problem.

The thermostat sends the engine temperature reading to the vehicle’s ECU. If that sensor doesn’t function as expected, it could trigger coolant restrictions that lead to other issues developing.

4. Warped Cylinder Head

If your vehicle receives a blown head gasket diagnosis, there is an excellent chance that a warped cylinder also exists. They must be even and straight for the engine to turn over and start.

Cylinder heads can expand when they receive excessive heat exposure. Once the engine cools, the new shape is sometimes retained. It is also possible for the expansion to cause the cylinder head to crack.

In an ideal situation, you’d replace a cracked or warped cylinder head with a new product. If this issue causes a slight variation, there is a chance that you or a mechanic could flatten it. When the damage is severe, replacement is the preferred option over a repair.

5. Battery Problems

When a car overheats and won’t start, the issue might have nothing to do with the engine. There could be a problem with the battery.

The battery is responsible for delivering power to the ECU and other vehicle systems. When it doesn’t have the resources to provide a complete signal, it can seem like the engine overheats or creates a complete seizure.

Replacing the battery is a relatively straightforward repair that almost any driver can do with a couple of tools.

  1. Remove the negative terminal from the battery.
  2. Remove the positive terminal from the battery.
  3. Most batteries are kept in place with a clamp or some sort of holding mechanism. You’ll need to loosen or potentially remove it to lift the battery out of its position.
  4. Once the old battery is out of the compartment, set it out of the way of the working area.
  5. Place the new battery in the designated location. You’ll need to add tighten the clamp, attach the positive terminal, and then the negative terminal.

Battery corrosion can limit power transfers, even when there is enough energy supplied to the vehicle. If you don’t see a clean metal-on-metal connection, clean the area with a mixture of vinegar and baking soda without the terminals connected.

Wipe dry, then restore the connection to see if your engine turns over.

Most drivers know that a battery problem exists when the cabin lights don’t turn on when entering the vehicle. You might also hear a clicking sound when turning the ignition if this issue is causing the car not to start.

6. Sensor Problem

Your vehicle has numerous sensors that help the various components function correctly. When one of them malfunctions, it can cause a cascade of issues that leads to your vehicle refusing to start.

When this problem exists, it is crucial to inspect your fuses to ensure one of them hasn’t shorted or blown. Some incidents are severe enough that browning or soot exists on top of the affected unit, but you may need to pull each one to ensure they’re functioning correctly.

You will need to inspect the ECU after reviewing the fuses to ensure there isn’t a problem lurking somewhere.

Whenever you find a faulty or damaged sensor or fuse, the item should be replaced immediately. If you’re unsure of what could be causing the problem, an OBD-II scanner can identify the codes that could be triggering warning lights or messages to display in the vehicle.

The FOXWELL OBD-II Professional Scanner is a simple diagnostic reading tool that can help you check for potential sensor malfunction codes.

It provides a straightforward control setup that lets you navigate the various menus, find the information you need, and erase the code after the error is resolved. It works with most vehicle makes and models, including 12V diesels.

If you don’t see a code, that doesn’t mean a sensor issue doesn’t exist. You may need to manually inspect each one to ensure this issue isn’t causing the seizure.

What Can I Do if My Engine Doesn’t Turn Over?

When your car won’t start and will not turn over, there could be a severe engine issue to correct.

If a seizure occurs, the engine might need to be hand-cranked to verify that any movement is possible. You can do this by turning the crankshaft manually with a half-inch breaker bar and the proper socket.

You may need to attach a section of pipe to the breaker bar for additional leverage, depending on where the crankshaft turn is for your vehicle.

Some engines turn better when the spark plugs are pulled. If you can’t get any movement at first, try taking that step to see if you can get anything to turn.

Older gas and diesel engines use a 27 mm head bolt on the front of the crank. You’ll need that or a 1-1/16-inch socket (sometimes listed as “17/16”) to complete the turn.

When you can’t get a turn even with the spark plugs out, a complete seizure is the likely problem. That doesn’t mean a repair is impossible, but you will need to evaluate the costs involved.

If you’re driving an older vehicle, the time and money it takes to purchase components and rebuild the engine could be more than the car is worth.

If you’re planning to tackle a seized engine problem yourself, here are the steps you can take to hopefully get it to turn over and start again.

Disconnect the Fittings

Most of the components found outside the engine assembly get their drive from the crankshaft. You’ll need to disassemble any accessory under the hood that gets driven by a belt as your first step.

That includes the water pump, power steering, and alternator. Once you have the items separated, you’ll find that it’ll be a bit easier to eject the piston when you’re ready.

Equalize Engine Pressure

You’ll need to remove the spark plugs next. If you already did this while trying to diagnose the engine problem, you’re already ahead of schedule.

It helps to mark the plug wires when disconnecting them to ensure your pattern remains the same when you’re ready to try turning the engine over another time.

This step is helpful because the pistons can release pressure against you while you’re working to free them. By taking out the plugs, you can equalize the environment.

Remove the Valve Cover

You’ll need a sturdy wrench to loosen the valve cover restraining bolts. Each cylinder has one that you’ll need to address.

Once the cover is gone, you can see the engine’s rocker arms. These items must be dismantled if you experience a complete seizure event. You’ll need to detach each nut that holds them in place.

Next, you need to pull the exposed rods from the cylinder head. This part of the process can take some effort.

Turn the Crankshaft

You’re now ready to turn the crankshaft to inspect the movement processes. Go in a clockwise direction unless your owner’s manual has a different request. Let the engine stay undisturbed for a few hours, so the parts are easier to remove.

Each damaged component must be replaced. If warping or cracking occurs, the engine will not function correctly, even with new parts.

Once you’ve finished with this step, you can reassemble everything to test if your engine will turn over.

Should I Rebuild or Replace My Engine After It Seizes?

If your car does not start, the problem could be with the battery or the engine. It helps to start reviewing the easiest potential issues first before proceeding to the complicated repairs. Many engines can be rebuilt, but it is more effective to install a new engine on late-model vehicles.

My car died on the way to school on Veteran’s Day. My baritone was in the back seat, and I was headed to a concert where I was to be a featured soloist.

I never got there because my engine block cracked. It turned out that my oil pressure gauge malfunctioned, so the vehicle wasn’t performing as it showed.

After deciding to do the repair myself, it took six months to rebuild the engine. It was a long series of late nights and weekends, but the day it turned over and started was a great one. It’s still a memory that makes me smile.

When your car doesn’t start, it can feel like the world is ending. If you have a plan to implement, such as the ideas outlined here, you can get back on the road in no time.


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