Cracked Engine Block – Should You Repair It or Sell Your Car?

Cracked engine block…those three words can be devastating to any car owner. You start to think about expensive repair bills and weeks without your vehicle. Before you hyperventilate, slow down and take a breath. A cracked block is not always as bad as it sounds, but there are some things you need to know so that you can make a decision on how to proceed. Should you repair the car or just sell it? If you decide to sell, how will you find a buyer for a car with a blown engine? Using the information outlined below should help you make the best decision for your situation.

What Causes a Cracked Engine Block?

You know that a cracked engine block is bad, but what causes this to happen? Let’s back up a couple of steps and talk about how you could find yourself in this situation. Engine blocks are typically made from iron or steel, and they are built to last. These metals are hard and durable, and they usually last for the lifetime of the vehicle. However, there are some things that can cause a failure.

While some parts of the engine block are thick and highly unlikely to crack, other parts are much thinner. The cylinder walls and small passageways in the block where coolant flows are much thinner and more prone to cracking. One of the main culprits of a cracked engine block is overheating. When your engine overheats, it causes expansion and contraction of the block at varying rates. When one part expands more than another, it can cause tiny cracks to form in the thinner portions of the block. Repeated overheating causes these cracks to become worse and can lead to a larger, detrimental crack.

Extremely cold temperatures can also cause a block to crack, especially if your car’s coolant is not at the proper level or concentrated enough. If you have filled your coolant tank with water and the temperature drops well below freezing, that water will freeze inside the engine. With nowhere else to expand, the freezing water pushes against the walls of the passageways and can cause a crack.

If you have decided to increase the performance of your engine through a turbo or supercharger, this greatly increases your risk of a cracked engine block. The increased pressure inside your engine from these parts creates an extreme amount of additional stress on your block. Cracks that occur as a result of this increased pressure are often catastrophic and often produce holes in the cylinder wall instead of small cracks.

Symptoms of a Cracked Engine Block

So, how do you know if you have a cracked block? There are several things you can look for that often point to a cracked block. The first thing is fluid leaks. If you notice oil or coolant leaking from your engine, this could be a sign of a crack. Oil and coolant should always be sealed, so any leaks could be coming from a crack in the block. The next thing you can look for is smoke coming from your engine. If you see smoke coming from under the hood, it is likely that oil or coolant is leaking onto the outside of the engine block and burning off. As it burns, it produces smoke that would be visible coming from under the hood.

Poor engine performance might also signal a cracked block. Since your engine compresses your air and fuel mixture in the combustion chamber, a crack would not allow the compression to build to appropriate levels. When this occurs, you will detect a noticeable decrease in performance. This symptom could also point to many other issues, so poor performance alone is not enough to verify a crack.

Engine overheating is another sign that could point to a crack in the block due to the coolant not circulating all the way through the block as it should. When the coolant cannot properly circulate, the heat from the engine cannot be removed. This causes the engine to run hotter than it should, and in some cases, it gets dangerously hot. Lastly, if you notice a mixture of your oil and coolant, there is a high chance that your block is cracked. Dirty, muddy coolant or milky, frothy oil means that those two fluids are mixing with each other, most likely in the passageways inside the engine because of a crack.

How to Repair a Cracked Engine Block

Even if you have confirmed that you have a cracked engine block, all is not lost. This is something that can be repaired, and sometimes for less than you think. If you suspect your block may be cracked, you should stop driving your car immediately. Before you attempt an engine block repair, have it inspected by a qualified mechanic to determine whether you truly have a crack or not. If so, you might be able to fix it with a sealant without tearing apart the entire engine. This would be the best case scenario. If this will not do the trick, then be prepared for a hefty repair bill.

More traditional methods of repairing a cracked engine block include welding, cold metal patching, or even replacement of the entire block. These methods are much more involved and require tearing apart the engine and putting it back together again. When welding a crack in the block, it must be repaired and smoothed back to its original state in order for the repair to be successful. Any imperfections or slight variations in the engine block can cause major problems down the road. You might even feel the engine shaking or shuddering when it is cranked.

If welding, patching, or block replacement is required, then the repair can require 30 hours or more of labor to complete. With mechanics’ labor prices running anywhere from $50 – $150 per hour, you could be looking at a $3,000 or more repair bill. This type of repair requires expertise that the average person does not have. You should also remember that welding or patching does not guarantee a successful fix, so it is possible you might have to replace the block in the end after all.

Is It Worth Fixing a Cracked Engine Block?

At this point, you might be wondering if it is even worth fixing your engine block at all. The answer really depends on your specific situation. If your car is newer and is generally in good shape, then it is probably worth it to spend the money on the repair. A successful repair would probably give you several more years of use from the vehicle. However, if you have an older vehicle that already has other problems, your money would probably be better spent investing in a new vehicle anyway. In some cases, you simply may not have the money available to perform the repair. In that situation, you could sell the vehicle and put the money you make toward the purchase of a car without major problems.

So, how do you find a buyer for a car with a cracked engine block? You could try listing it in the online classifieds and hoping for a buyer that way, but that method could take some time. Another option is visiting the local junkyard and attempting to get an offer from them. However, you are likely to get a lowball scrap offer from them based purely on the value of the scrap metal in your car. While this would put some money in your pocket, it probably is not the most money you could get.

Thankfully, there is a better way. There are nationwide car buying services out there who will pay cash for your vehicle regardless of its condition. Even with a cracked block, they will make you a cash offer and come tow the vehicle away at no charge. You can then use that money to upgrade to a vehicle that runs smoothly. Many of these services are straightforward and easy to use, and you can often have money in your pocket within a day or two.


Cracked engine blocks are no small issue, but it does not mean that you should immediately scrap your car. Sometimes, minor cracks can be easily fixed with the use of a commercial sealant without ever tearing into the engine. Other times, major repairs are required and will set you back quite a hefty sum of money. Either way, you should assess your specific situation to determine whether you are better off repairing the car or just selling it and moving on. Using the tips here, you can make an informed decision that makes the most financial sense for you. If you decide to sell, there are ways that you can easily find a buyer and get paid in cash quickly. Otherwise, make sure that you find a qualified mechanic who will perform the repair well so that your car can get back on the road and stay there for many miles to come.