The dreaded oil leak, there is nothing worse than coming out of your girlfriend/boyfriends’ parents’ house and noticing a large oil right smack dab in the middle of their concrete driveway.
Oil leaks can range from small annoying little drips to large all the oil on the ground beside your vehicle catastrophes. Knowing when an oil leak needs to be repaired or where it is coming from can help you avoid certain disasters.
What Causes an Oil Leak?
We are all familiar with the idea that our engines need lubrication to run properly and to ensure the most longevity possible. This lubrication is completed inside of our internal combustion engines with a lubricant known as oil.
This oil is a slightly viscous lubricant that is distributed through the vehicle via what is called an oil pump. The oil pump pressurizes the oil and distributes it through channels in the engine known as oil galleries.
Vehicles require different amounts of oil depending on their design and their individual engine requirements. This amount of oil can range from 3.5L all the way to 25L or more on larger engines in heavy equipment or highway transport trucks.
This oil needs to be contained inside of the engine and allowed to travel through the various galleries inside of the engine without leaving the engine.
The various components are sealed together using many different types of gaskets and sealers. These sealers can range from a simple oil-safe silicone to a technologically sophisticated multi-layer steel head gasket.
When these various types of gaskets fail, that is when the vehicle’s engine will develop what we know as an oil leak. This is where oil leaks from the engine, generally dripping on the ground.
Or the driveway of your significant other’s parents. At least that seems to be my luck.
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How Much Does it Cost to Fix an Oil Leak?
The amount it costs to fix an oil can vary significantly. One of the most common oil leak repairs is a valve cover gasket.
The valve cover is a component that seals various moving engine components that are known as the valve train. It is very common for these valve cover gaskets to leak, especially on older vehicles. Older vehicles were very common to use a simple cork gasket that would seal the valve cover to the engine’s cylinder head.
This cork gasket was very susceptible to breaking down and eventually leaking. This leak would start as a small leak and progressively get larger if not repaired in a timely manner.
To repair an oil leak, it will usually demand repairing valve cover gasket, so the price can range from $150 to $1500 depending on the vehicle make and model and engine size.
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Another common source of an oil leak is crankshaft seals. The crankshaft is a component that rotates via the connecting rods and transfers the rotational torque of the engine to the various accessory components. It also drives the torque converter or clutch depending on what type of transmission your vehicle is equipped with.
Because the crankshaft needs to have access inside and outside the engine there are special gaskets known as crankshaft main seals. These seals allow the crankshaft to rotate while ensuring that the engine does not lose precious oil from the crankcase.
These seals will fail over time but can also damage the crankshaft when the vehicle’s engine reaches high mileage. If this happens the seal will leak due to a large groove being worn into the crankshaft assembly. The only way to repair this is to use an item that is made by a company called SKF.
This item is called a Speedi Sleeve. It is basically a small sleeve made of stainless steel that slides over the damaged section of the shaft. Once this is completed you install a new seal, and the oil leak is fixed.
As you can see there is a multitude of different areas that an engine can start to leak oil. There is also a large number of reasons that those seals may leak. Seals may fail due to age, deterioration, or damage but can also be popped.
If the engine creates too much crankcase pressure due to a faulty positive crankcase ventilation valve it can cause the seals to effectively “pop” causing an excessive oil leak.
Can You Drive with an Oil Leak?
Vehicles can be driven with an oil leak but in many cases, it’s not worth the risk. Even a small leak can cause damage. Oil leaking from a valve cover can be slow but over time this area can cause oil to leak onto the alternator causing extensive failure which would require replacement of the alternator to correct. This could turn a small repair bill into a very fast bill rather quickly.
The oil that is seeping from the engine can also leak onto the drive belt. If this happens the oil can contaminate the belt eventually leading to it slipping or possibly even breaking due to contamination.
Hoses can also be damaged in this manner as well. If oil leaks onto a lower rad hose for example can cause the hose material to deteriorate and eventually the pressure in the cooling system will cause the hose to explode. This would leave a driver on the side of the road stranded for sure.
The other question that I have dealt with over the years as an automotive mechanic is will it get worse? This is a question that has no answer. I have seen vehicles have a small oil leak that never got worse for years. Oil leaks have also gone from being small seeps to fully leaking to the point where the engine will lose all its lubricant and cause internal engine failure.
This situation can occur if an oil pan is corroded and leaking. Eventually, this will continue to leak to the point where a severe oil leak can develop. At this point, you could be driving down the road and the only way you know it is too late is the stalling of your engine because it is now seized.
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Is it Worth Fixing a Small Oil Leak?
Fixing a small oil leak is definitely worth it because a small leak might cause damage. Oil leaking from a valve cover can be slow but over time this area can cause oil to leak onto the alternator causing extensive failure which would require replacement of the alternator to correct. This could turn a small repair bill into a very fast bill rather quickly.
The above reason is the largest reason to fix a small oil leak as soon as possible. It is also good to remember that a small leak is only ever going to get larger. It is not very often that an oil leak fixes itself.
There are many products sold at leading automotive retailers that promise if you pour their product into the engine, it will fix the oil leak. These products can be thought of as snake oil, they rarely work. You also need to wonder what other damage this is causing to your engine’s oil.
This is why you need to ensure that you fix the leak properly before it gets worse. You always need to remember the old saying, “An ounce of prevention, is worth a pound of cure”
When can You Fix an Oil Leak by Yourself?
If you are an experienced DIYer it is possible to fix an oil leak yourself. There are simple oil leaks that can be repaired, such as a valve cover gasket or timing cover gasket. These repairs are as simple as removing a few components from the engine, removing the old gasket, installing a new gasket, and finally re-installing all of the previously removed components.
Once you have completed a repair it is always very important to ensure that you confirm your repair. For an oil leak, that means topping up the oil to the proper level and running the engine for a long period of time. After this time period, you will check the area that was previously leaking to ensure that you have properly fixed the issue.
When Do You Have to Pay for an Oil Leak Repair?
There are other times when you should call a professional to complete the repair. A perfect example of this is if you have a cylinder head gasket that is leaking oil. This repair is a very sophisticated repair.
Once the cylinder head is removed there are many important precise measurements that need to be completed to ensure that the cylinder head and engine block are still in good condition. If these measurements are not taken the cylinder head gasket will most likely develop an oil leak again in the near future.
If all these measurements are okay the technician still requires specialized tools to be able to torque down the cylinder head to the correct manufacturer’s specifications.
Oil leaks may seem like a small issue, but they can have serious consequences for vehicle owners. Small leaks can develop into large leaks. Large leaks if not looked at can sometimes start engine fires. General Motors even once had to recall over 1.4 million vehicles for this reason. So, if you are ever in doubt take it to a professional to get their opinion on what you should do with that pesky oil leak.
Oh, and by the way, maybe go over and clean your significant other’s parents’ driveway. Please.