JLM Oil Stop Leak

250ml / J06055
JLM Oil Stop Leak

Worn engine oil seals create leaks that are messy, bad for the environment and your wallet. While replacement seals tend to be inexpensive, accessing them tends to involve significant dismantling and high garage labour bills. JLM's Engine Oil Stop Leak additive provides an inexpensive solution.

Product information

As they age, oil seals lose their flexibility, which affects their sealing properties. This process worsens on engines that have suffered from neglected oil changes, or endured low-quality (or incorrect specification) lubricant that contained insufficient oil seal preservative additives. JLM's Engine Oil Stop Leak contains the latest in seal-swell additive technology that helps restore their pliability, which also compensates for a degree of wear on the seal lip surface.

JLM Lubricants' Engine Oil Stop Leak also supports the lubrication system of an older engine, by enhancing oil viscosity slightly. Additional benefits include the potential to improve both oil pressure and cylinder compressions, along with the possibility to reduce the quantity of lubricant burnt within the combustion chambers, thus reducing oil consumption further. For cars that suffer from excessive oil consumption but exhibit no external leaks, JLM's Stop Smoke offers a more targeted solution.

For these reasons, JLM's Engine Oil Stop Leak is beneficial for older, higher mileage engines. It does not offer a solution for oil seals that have collapsed, or have suffered from mechanical damage, such as a puncture.


Engine Oil Stop Leak fits JLM Lubricants' company policy of offering cost-effective but advanced chemical solutions that are straightforward to use.

While it can be added to the oil at any point, JLM recommends dosing at service time. An oil-flush additive should be added to the sump, for which JLM Lubricants recommends its Engine Oil Flush, before the old oil is drained and the fresh lubricant added.

Substitute 250ml of the new oil with JLM Lubricants' Engine Oil Stop Leak. 250ml JLM Engine Oil Stop Leak treats 3 to 6 litre of motor oil. Never overfill the sump, which risks causing additional problems, such as pressurising the crankcase that risks increasing oil leaks.

As its seal-swell ingredients are so effective, it should not be used in other hydraulic systems, such as automatic gearboxes, Dual Clutch Transmissions (DCT), or power steering systems. It swells all rubber components within those systems indiscriminately, affecting the intended operation and may even enhance wear. JLM's Engine Oil Stop Leak is strictly for the lubrication systems of combustion engines, only.

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