The engine of a car is perhaps the single most important piece of machinery in the whole vehicle. It gives your car life, controls crucial aspects of its functionality and is the heartbeat of its movement.
Therefore, when it is broken or not working properly, it can be disastrous. Here, we look at how to fix a blown engine, as well as tips and hints for keeping your engine in top condition.
A blown engine can be every driver’s worst nightmare – leaving your car unable to function and leaving you potentially quite a lot out of pocket, if its fixable at all.
The car engine works by transforming heat from burning gas into the mechanism that turns the wheels on your vehicle and keeps it moving at variable speeds controlled by the driver.
Due to its complex mechanism and vital importance to any vehicle, making sure that your engine is kept in optimum condition in order to avoid the potential of a blown engine is greatly important to the health of your car.
No matter how well you look after your car, however, unexpected things can happen. Here, we take a look at what a blown engine is and how you can fix it if it happens.
What Is A Blown Engine?
The term ‘blown' is of course quite vague, so it is worth defining, in automobile terms, exactly what constitutes a blown engine. The most obvious blown engine occurs when a broken connecting rod punches a hole in the block, or the crankcase.
A connecting rod is the part that connects a piston, which is moving up and down very quickly, to the rotating crankshaft and will make noise when it punches a hole, as well as leaving substantial damage that will leave you knowing the engine is ‘blown' open.
When the rod is broken, the crank still continues to keep turning and can push the broken rod right through the side of the cast iron or aluminium block or the crankcase, which holds the oil, and this is where you need to be cautious.
When this occurs, the engine will stop immediately and beware the oil escapes through the damaged block or crankcase and onto the exhaust, which could even cause a fire and definitely cause some smoke, so safety is paramount.
A blown engine may also occur when a broken valve punches a visible hole through the top of a piston. In this case, the pressurized oil will escape through the top of that piston out through an exhaust valve and you will see it come out of the exhaust.
Signs Your Engine Is Blown
In all of these scenarios, the visual evidence of a blown engine is obvious to most drivers, alongside the fact that the engine will, in almost every case, stop running immediately. You will also likely hear a substantial noise when the engine is blown.
Although most of the signs you have blown your engine are clear, it is important that drivers are aware of a blown engine as soon as possible as attempting to restart or drive your car can cause more damage and reduce the of be able to fix a blown engine.
Exhaust Smoke – White Exhaust
The most common signs come from the car's exhaust. If the engine is emitting while smoke from your car’s exhaust pipe, this could be an indicator that engine coolant or water is coming into the combustion chamber, a sure sign that the engine could be blown.
The exhaust smoke will look dense and linger in the air unlike that of normal exhaust smoke when the engine is running fine.
Blue exhaust is more of an indicator and can indicate that your engine is on the way to being blown rather than it happened yet. Blue smoke may billow from your tailpipe and may be an indicator that raw engine oil is entering into the combustion chamber.
Spotting this early can help you prevent lasting damage and stop your engine from being follow blown – meaning an easier fix.
Sounds From Your Engine
Noise from the engine is never a good sign and can indicate damage or even that the engine has blown already. These noises are generally caused by broken elements within the engine and will sound like knocking or rattling as they jangle against each other.
Engine Refusing To Start
Perhaps the most obvious one. Anyone who owns a car will know that a car engine refusing to start could be down to a large number of issues, but a blown engine is definitely one.
Overheating, timing or mechanical defects can all cause this and if you continue to try and start the engine without properly addressing the issue, this can lead to further damage.
Coolant is Entering The Engine Oil
The car’s engine oil and cooling systems are always kept separate as well as sealed inside the engine. When the two mix – as is not supposed to happen – this is a sure sign that there is something wrong with the internal workings of the engine, including it may be blown.
How To Fix A Blown Engine
If you have established that your engine is indeed blown, your next question will be is it possible to fix it, and if so, how. As with most car faults and broken parts, the problem is exasperated if you fail to diligently examine what is the cause and prepare for it.
First and foremost, do not go out buying a ton of engine parts without proper knowledge or preparation. For this, it will require you to know what you are doing.
You should consider dissembling your engine so you can get to the bottom of the root cause of the issue. This may not always be necessary, but where it is you should think about this meticulously and treat it like an autopsy.
Establish What Needs To Be Fixed
First, you should try to diagnose the engine during teardown phase. It's important to go slowly and be organized in your approach. Remove the valve covers and intake manifold, checking for debris in the oil and broken valve springs/valve train components.
Then you should remove the cylinder heads and examine the piston tops and combustion chamber roofs for signs of oil leakage, water leakage and melted components to see if there is anything leaked that should not be that cause the blown engine.
Checking The Engine Thoroughly
You should check for cracks in numerous parts of the engine; including the heads, the combustion chamber, the piston tops, the deck surface, and the cylinder bores, as well as the engine block deck surface. You can be brief here, but make sure.
If your untrained eye doesn't see anything, don't just figure the engine is fine. Cracks that appear invisible may only be viewable by a professional at a machine shop so it may be necessary to visit, even more if overheating was the primary cause of the blown engine.
Now you should remove the crankshaft, rods and pistons from the engine. While you are doing this, it is important that you pay close attention to the bearing surfaces, checking for any noticeable signs of gouging and adjusting your method accordingly.
Send Block To Automobile Shop If Needed
Send the block to the machine shop to have the crankshaft, bearing bores, cylinders, engine block and cylinder head deck surfaces machined to factory specs. Order whatever new parts you need, including over-sized pistons, rings and bearings.
Installing The Piston Rings
Install the new piston rings onto the pistons. Install the crankshaft bearings into the block, followed by the crankshaft itself, rod bearings then the pistons and connecting rods. Pack the oil pump with petroleum jelly, then install it and the oil pan.
Filling The Engine
This is a crucial step. Here, you should insert the new head gaskets and bolt the heads onto the block. Slide the new camshaft lifter in place. Install the camshaft either into the block or onto the cylinder heads and then install the valve train onto the heads section.
Install the intake manifold gaskets, intake manifold, exhaust manifold gasket, exhaust manifold, valve cover gaskets and valve cover and make sure that everything is in its correct place, forming a durable engine with no loose parts.
Now, fill the engine with oil then use a drill and priming shaft to prime the oil pump. For many engines, the oil pump drive shaft is accessible through the distributor hole. If possible, have someone help you while doing this by turning the crankshaft with a wrench.
You should see that oil is now pushing through the valve train. This is a good sign and means that the engine is ready to install. Once installed, fire the engine up and lightly make sure that it is working fully before using it to full capacity. You're all set.
Looking After Your Car Engine
Of course, these fixes are all well and good but what would be great is if the engine wasn't blown in the first place, right. These are a number of tips and hints that go towards maintaining a healthier engine so that you can avoid issues such as a blown engine in the future.
Firstly, make sure that you check the oil regularly. This is really important the older your car is.
Replacing worn-out belts, getting a regular tune up and making sure that the coolant is working properly in order to avoid problems such as overheating that can create bigger mechanical issues with your engine will all help minimise the chance of it blowing out.
If You Decide Against Trying To Fix A Blown Engine
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