How much should I add at each oil change?

Lucas recommends adding enough to replace a portion of your regular oil volume. For most passenger vehicles, 1 to 2 quarts mixed with your regular motor oil is a common starting point. Refer to Lucas Oil's guidelines for your specific application.

Will this work on a rear main seal leak?

Lucas Oil Stop Leak is designed to condition and renew worn seals, including rear main seals. It works best on seals that are dried out or shrunken rather than physically torn or cracked.

Can I use this with full synthetic oil?

Yes, the formula is compatible with petroleum, semi-synthetic, and full synthetic motor oils. It blends in without affecting the oil's performance characteristics.

Lucas Engine Oil Stop Leak — 1 Gallon

Name: Lucas Engine Oil Stop Leak (Gallon)
Brand: Lucas
SKU: LUC10279
Price: 25.82 USD
Availability: InStock

Lucas Engine Oil Stop Leak (Gallon)

$25.82

Usually ships the next business day

Oil stop leak additive that renews worn seals without harmful solvents. Compatible with petroleum, semi-synthetic, and full synthetic motor oils. 1 gallon.

Key Features

Renews worn engine seals without harmful solvents.
Compatible with petroleum, semi-synthetic, and full synthetic motor oils.
Helps reduce oil consumption and engine noise.
Gallon size treats multiple oil changes.
Contains no solvents that can corrode seals over time.

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Product Details

Oil spots on the driveway usually mean aging seals, and Lucas Engine Oil Stop Leak is formulated to address that problem from the inside out. This gallon-sized bottle contains enough additive to treat multiple oil changes, making it practical for shops or vehicle owners who maintain several high-mileage cars.

Unlike some stop-leak products that rely on harsh solvents to swell seals temporarily, Lucas uses a solvent-free formula that conditions and renews worn seals over time. It blends with petroleum, semi-synthetic, and full synthetic motor oils, so you do not need to worry about compatibility with whatever oil you are currently running. Users commonly report reduced oil consumption, lower engine noise, and improved oil pressure after the additive has circulated for a few hundred miles.

The gallon size at a ship weight of 10 lbs makes this the bulk option. If you are treating a single vehicle, a little goes a long way — you typically add a portion at each oil change rather than dumping the full gallon at once.