Is It Normal for an Old Car to Leak Oil? And How to Stop It

We have all been there. You are heading out and as you pull out of the driveway, there is a dark spot that you are sure wasn't there when you parked. An oil leak. Now you have to decide whether or not your car leaking oil is a huge sign of trouble for your vehicle or if it's just another of those things that happen to old cars. How much of a problem is this? Plus, is there a possible way to fix a car leaking oil without having to invite the mechanic?

Oil leaks highlights

• Level of urgency:medium
• Average mileage:over 50,000 miles
• Repair cost:$200 - $1,800
• DIY repair:only in some cases
• Commonreasons:head gasket, other gaskets, seals, fasteners
• If ignored:low engine oil level, contamination of units under the hood, engine damage
• How to solve:locate the leak and repair the system that is leaking

Are Oil Leaks from an Old Car a Big Deal?

All kinds of oil leaks can be potentially dangerous, so yes, you should be concerned if you notice your car dripping engine oil. But this is not a reason to panic at the sight of dark oil spots on the ground. What should matter the most now is the level of oil left in your car and how bad the leak is, so check for those. 

What might seem like a few drops of oil can grow into larger leaks and cause problems that may be more expensive to repair. Oil leaks certainly never get better with time, only worse, so topping the oil to finish your trip might work as a temporary fix, but you have to address the cause of the leak. 

The worst types of leaks are those that go unnoticed and leave your vehicle running on low levels of engine oil. This is why you should always check your oil levels, especially since your car is a classic and may not have a low-level warning light.

If you are lucky enough to observe the leak before leaving home, it is best not to start your engine. The large puddle of oil on the ground is a sign that your car might be lacking sufficient oil to lubricate the engine. Ignoring the leak, in this instance, can cause engine seizing, a much bigger issue. 

But first, what can cause an old car to leak oil? Age? Damaged parts? 

Why Your Old Car Might Be Leaking Oil

There are countless reasons why your car might be leaking oil, the same way leaks can occur in different parts of the vehicle. Let's consider a few common locations oil can leak from.

• Crankshaft seals 

The crankshafts protrude slightly from both ends and help you mount the flexplate. There is a seal at each end to prevent oil leaks but sometimes, the crankshaft seal might be too small and oil starts to accumulate on the underside. You might notice the oil in front of the engine if the leak is severe. 

• Oil filter and drain plug 

Each time you change oil, you take out your vehicle's oil drain plug and oil filter. It is easy to see why these spots are an easy target for leaks. Removing and reattaching the components frequently increases the possibility of leaks, especially in old cars where both parts have undergone long-term use. 

• Oil pan gasket

The oil pan gasket is the seal between the oil pan and the engine block. It is another common location for oil leaks but luckily, as little as replacing the gasket can solve the issue. 

• Valve cover gasket

This part is often associated with oil leaks from the top of the engine. That is where the gasket is located and it acts as a seal between the cylinder head and the valve cover. Since your car is old, its ability to seal off the oil might have reduced, leaving the valve cover gasket covered in oil.

• Timing cover seal

Whether your classic car engine has a timing belt or chain, the timing cover protects it. The timing cover seal ensures that oil remains inside the timing cover but this seal can wear out with prolonged use. When this happens, oil begins to escape. In some cases, the timing cover itself rather than the seal is what gets weakened. You'll have to inspect the car to know which of the two parts will need replacing. 

• Cylinder head gasket 

Head gaskets are mostly associated with internal leaks but they can also cause engine oil to drip externally. If your classic car uses a flat engine, this might be one of the first places you want to check when experiencing a leak. 

• Oil filter adapter housing seal

The adapter housing your oil filter connects to might have a gasket behind it that can become faulty. Cars with cartridge filters can also leak from the oil filter housing seal. 

Locating Oil Leaks

Now you know the common vehicle parts that the oil leak may be coming from, so what next? How do you figure out the affected location without the mechanic's help? 

If you suspect you are dealing with multiple leaks, it's best to focus on finding the highest leak and repairing it. Else, the oil will run down and affect every other part below. Clean the engine after fixing the upper leaks and then wait to see if you notice any more leaks. You can drive the vehicle to test for additional leaks. 

Determining the leak location in old cars can be challenging. Sometimes, using a black-light-sensitive dye helps. Mix the substance with the oil and it can help detect leaking when you use a black light. 

To figure out if there is a leak at all, use a dipstick to measure your car's engine oil level. Levels below the minimum mark are low and can be a sign of an oil leak. You may also notice blue smoke emitting from the car's exhaust when the car is running. 

How to Stop an Old Car from Leaking Oil

Unless the leak is severe, you can fix leak issues in old cars. You'll need simple tools like a car jack, torque wrench, jack stands, and replacement parts if necessary. Of course, how you approach the repair depends on where the oil leak is coming from. Here are ways to fix the most common type of oil leak:

• Valve covers 

The first thing to do is to remove the valve covers and clean the cylinder head and gasket surface. Make sure you are using the right cleaner here especially if your car model has a steel valve cover. 

You are trying to uninstall and tighten the valve cover so place it on a firm surface and flatten the area around the bolt hole with a hammer. Now, try reinstalling the cover while making sure not to over-tighten the bolts to avoid damaging the cork basket. 

• Oil filter leaks 

As mentioned earlier, the oil filter and other pressure-sending until are common areas that often experience leaks. Simply replacing the affected unit often fixes the leaks. If your car uses the canister-style filter, remove the rubber seal that holds the filter canister. Sometimes, the rubber seal weakens, breaks off, and enters the seal groove. You need to check for this issue before re-installing the new sea.

• Front crankshaft 

The front crankshaft is often a problem area because as the oil seals age, they can crack and cause a leak. Replace the unit by removing the harmonic balancer. Get a harmonic balancer puller to do this. Inspect the area where the balancer holds the seal and make sure it is smooth enough. If not, get a repair sleeve kit and fix that problem so the new seal can function effectively.

• Oil pan gasket

Clean the oil pan gasket before beginning any work on it. The process of fixing this unit is similar to how you would treat a valve cover. Flatten the distorted area around the bolt holes to ease the reinstallation process. You can apply the product to coat the edges of the oil pan gasket.

• Rear engine seals

How you fix oil leaks from rear engine seals depends on the type of seals your car has. Remember to grease the seal before reinstalling it, and ensure its angled edge is facing inward. 

Conclusion

Sometimes, fixing an oil leak in an older car requires mechanical skill, so you will need to call an expert. But in cases of little leaks, try one of the techniques to see if it helps. Oil leaks can be a fire hazard and cause additional damage to your car that will require more expensive repairs. This is why it's a terrible idea to ignore a leak, even if it's just a few drops.