Stop Leak Oil Additives: How They Workand When to Use Them

Have you ever noticed that as your car gets older, it just never quite runs the same as when it was new? That’s because overtime, your engine succumbs to wear and tear as well as collecting all sorts of debris from the outside that gets trapped inside your motor and other moving parts of your car.

This is just a natural aging process and although it can’t be stopped, it can definitely be slowed down and sometimes even reversed with oil additives.

The older your car gets, the more you should probably be considering using an additive to help clean out your engine and add some additional lubricating properties.

Another thing that many people aren’t aware of is there are also additives that can stop small leaks from forming and even plug up smaller ones just using oil additives manufactured with these ingredients.

This can literally save you from a blown engine which happens when you don’t have enough oil in the crankcase and the motor overheats. Especially with older cars, your oil light might not be as dependable as you think. But using oil stop leak oil additives can help prevent something like this from happening to your car.

If leak oil additives are something new to you, this is the place to read up and get to know what the benefits and the risks are when it comes to using them in your car or truck engine.

Types of Leak Oil Additives

Please be aware that while these types of oil additives can help with small or even tiny pinhole leaks, don’t expect them to do magic on larger problems. They’re simply not designed for that. These additives do give you an easy fix for a quick repair, but even then the repair may not be permanent and it’s best to get a mechanic to see just how bad the leak is. But these leak oil additives do come in handy for the short term!

Petroleum-Based Additives: Petroleum-based additives have a natural oil base and aren’t considered synthetic chemicals in any way. They work by swelling the gaskets and seals in your engine so they make a tight seal against the metal and don’t leak. And although this can be helpful in certain situations, they can also cause your seals to degrade prematurely. So you need to be careful using this type of additive if you’re going to be using it for a long period of time.

Synthetic Additives: Synthetic leak oil additives are chemical compounds and don’t contain any ‘regular’ oil per say. The good thing about these types of additives is that they are specifically formulated to stop leaks, and work fast and don’t harm the engine’s seals like petroleum based products do. And since they are compounds, most formulations also include other types of oil additives that can help other issues all in one can. Their only downfall is they are definitely more expensive than petroleum-based additives.

Oil Stabilizers: Oil stabilizers, or oil treatments, work like a viscosity improver as they thicken your car’s oil to a point it becomes thick enough not to leak out the gaskets. Although this can seem like a good thing short term, it also means you’re messing with the viscosity of the oil and it’s not at its optimum which could cause other issues down the road.

Stop Leak Additives: Stop leak additives are specifically designed to do what they say, stop leaks. You may be more familiar with the stop leak products that are sold for stopping radiator leaks. They’re quite common.

The oil additive varieties are a bit different and come in a few types, those that are oil based and the synthetic kind. Both of these work by expanding so that they fill any gaps, cracks or pinholes that can form throughout your car’s oil system.

But again, they aren’t meant to be a fix all, or really even for long term use. They’re great for the older car that is just leaking a tiny bit of oil here and there, but anything more and you should go and see a proper mechanic.

Deciding which to buy really depends on how deep your pockets are. If you want and can afford the very best, then the synthetic types of additives are hands down the best. They’re just not as affordable as the oil-based variety.

Synthetics are better because you can use them to stop leaks but they don’t hurt other parts of your car like the oil based products can. Oil based leak stop additives tend to destroy your car’s seals over a long period of time. So unless you plan on not having your car long, or you’ll be getting whatever is wrong fixed soon, you’re best bet is to stick with the synthetic stop leak additives.

How Leak Oil Additives Work

There are three important ways a leak oil additive can work, as a swelling agent, a conditioning agent or a viscosity changer. The way in which they work will totally depend on the additive you’re buying and how it’s formulated.

Swelling Agents: These do exactly what they say, they swell your seals, gaskets, and O-rings to expand just enough to make a complete seal and stop your leak. They do this using synthetic chemicals that react with the non-metallic parts of your engine. This also helps older parts keep their original shape and can often help in a matter of hours once the engine has been warmed up long enough.

Seal Conditioners: Over time your seals can become brittle and dried out which of course leads to cracks and them not staying to their original shapes. All of these can cause small gaps that can leak oil. The chemicals in these types of leak oil additives work similarly to you putting on face cream to rejuvenate the cells of your skin. They give subtleness back to the rubber parts allowing them to conform back to their original shapes and expand to stop any leaks.

Viscosity Modifiers: These types of additives are what we recommend the least. This is because they work by thickening your oil, thus making it too thick to leak through whatever the problem is. And they do work. The problem though is when you play with an oil’s viscosity, you are also making it perform differently than it was intended. That means it now may be too thick for your car’s needs and not working to coat the engine’s internal parts the way it is supposed to be. So as a quick fix they’re helpful, but this should be your last choice and considered only a temporary fix!

When to Use Leak Oil Additives

If you notice a spot of oil on your driveway, or you’re noticing the engine oil light blinking every week or more, it’s time to consider using one of these leak oil additives. Like we’ve said before, they’re meant for small leaks, not major repairs and there’s only so much these additives can do. So be realistic when using them.


These types of oil additives are never recommended or even intended to be used as an alternative to proper maintenance. Especially when it comes to oil leaks, there are times you’re just going to have to go to the mechanics shop and get things fixed correctly.

But short term these leak oil additives can come in quite handy and can indeed fix small leaks and possibly even rejuvenate parts of your car’s engine. It is possible you won’t need to do any costly repairs for a long time if you’re using these, but sooner or later if your car is getting older and you haven’t been the best at keeping up with a proper maintenance schedule, you’re going to have to get a more permanent fix done.


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