Best Diesel Engine Oil Stop Leak: Compare 10 Additives

#1 · Best Overall

1. Bar's Leaks OS-1

• Weight: 1.1 lb
• Compatible with Vehicle Type: Car, Truck
• Container Type: Can
• Size: Pack of 1

Best for: Diesel and turbo leak candidate.

Why it ranks #1: It explicitly works in diesel engines, targets main seals and gaskets, and lists turbocharged engines among its compatible applications.

Bar’s Leaks OS-1 explicitly covers diesel engines, including turbocharged applications, and targets leaking main seals and gaskets. That stated engine range gives diesel owners a defined compatibility point, while its additional focus on worn valve seals and guides broadens its relevance when oil burning accompanies a leak.

OS-1 is described for gasoline and diesel engines, with turbocharged, EcoBoost, hybrid, and racing applications also named. That breadth helps buyers assess whether their engine type falls within the stated use, rather than relying on a generic seal-treatment claim. It targets main seals and gaskets and is also said to renew worn valve seals and guides. The product description sets a candid suitability boundary: the vehicle should not consume more than one quart of oil per day.

Skip it if you need a treatment explicitly listing diesel use but do not need OS-1’s one-quart-per-day consumption threshold; consider the listed use carefully.

This is a relevant option for diesel owners with leaks or oil burning who fit its stated consumption boundary. Its named coverage includes turbocharged engines, but the product description rules out vehicles consuming over one quart daily.

Listed on Amazon as: Bar's Leaks OS-1 Oil Seal Engine Oil Burning/Leak Repair, 16.9oz, 1-Pack

#2 · Diesel-Compatible Formula

2. BlueDevil Oil Stop Leak

• Weight: 4.8 oz

Best for: Gasoline and diesel leak treatment.

Why it ranks #2: Its supplied description confirms compatibility with gasoline or diesel engines and identifies the product as a non-clogging engine-oil leak treatment.

BlueDevil explicitly lists compatibility with gasoline and diesel engines, giving diesel owners a clear engine-type match. Its liquid is described as non-clogging and intended to seal seeping or dripping oil leaks permanently, while the pour-in approach keeps the stated application centered on the leaking component’s oil sump or crankcase.

The application description says to pour the recommended amount into the leaking component’s oil sump or crankcase, a familiar oil-system route for buyers handling the treatment themselves. BlueDevil names gasoline and diesel compatibility and describes the formula as non-clogging and harmless to the engine. It claims a permanent seal that remains sealed after miles of driving. The supplied information does not give a specific recommended dose, so the application amount needs to be determined from the product directions.

Skip it if you need a stated treatment volume in the supplied facts; Lucas Oil 10278 is identified as a one-quart bottle.

This fits diesel or gasoline owners seeking a pour-in treatment for seeping or dripping engine-oil leaks. Its stated compatibility and non-clogging claim are useful, but the supplied facts leave the recommended dose unspecified.

Listed on Amazon as: BlueDevil Products 49499 Oil Stop Leak – 8 Ounce

#3 · Multi-System Use

3. SealLube Stop Leaks

• Weight: 1 lb

Best for: Multi-system seal treatment.

Why it ranks #3: It explicitly lists diesel engines alongside marine engines, tractors, hydraulic systems, and transmissions, making its stated applications unusually broad.

SealLube lists diesel engines alongside transmissions, power steering, differentials, and hydraulic systems, making broad fluid-system coverage its defining feature. Its stated action restores flexibility, elasticity, and tensile strength in rubber seals, a fit for buyers addressing leaks across more than one type of system.

For diesel engine owners, the listed engine coverage provides a direct use-case match; the same product description also names marine engines and farm tractors. SealLube’s stated rubber-seal restoration connects flexibility, elasticity, and tensile strength with its leak-stopping purpose. Its cross-system list includes manual and automatic transmissions, power steering, and hydraulic systems, useful where one product is being considered for varied equipment. The description says it works in hours and lasts for years, without specifying a dosing procedure here.

Skip it if you want a diesel-specific formula with straightforward engine-oil application; Bar's Leaks Rear Main Seal Repair specifies adding it to the crankcase.

This suits owners managing varied equipment and systems who value the stated rubber-seal restoration and broad application list. Buyers seeking a diesel-engine-only treatment or a clearly stated crankcase procedure may prefer a more narrowly specified product.

Listed on Amazon as: Stops Leaks: Gasoline Engines, Diesel Engines, Automatic Transmissions, Manual Transmissions, Power Steering, Rack and Pinion, Differentials and Hydraulic Systems – 8 oz.

#4 · Quart Bottle

4. Lucas Oil Stop Leak Quart

• Weight: 0.92 kg
• Compatible with Vehicle Type: Car
• Container Type: Bottle
• Size: Quart

Best for: Mixed-oil-type seal treatment.

Why it ranks #4: Its quart bottle offers a middle size, and the product states compatibility with petroleum, semi-synthetic, and full synthetic motor oils.

Compatibility with petroleum, semi-synthetic, and full-synthetic motor oils is the key practical feature of Lucas Oil Stop Leak. That range lets buyers select it without switching oil types, while its stated seal-renewing action targets worn seals and its listed effects include reduced engine noise and oil consumption.

Lucas says the formula renews worn seals without risk of damage or eventual corrosion, giving buyers a seal-focused option rather than an oil-type-specific treatment. Compatibility with petroleum, semi-synthetic, and full-synthetic motor oils supports use across those oil choices. The product also claims to reduce engine noise and oil consumption while raising oil pressure. Its one-quart bottle is a substantial amount to handle, so buyers should consider their engine’s requirements before adding it.

Skip it if you need a product explicitly listed for diesel engines; Bar's Leaks OS-1 names diesel compatibility.

This suits a car owner seeking a seal-renewing additive that works with several motor-oil types and values the stated noise and consumption benefits. The supplied vehicle compatibility is car-focused, so diesel buyers should weigh that boundary.

Listed on Amazon as: Lucas Oil 10278 Engine Oil Stop Leak – 1 Quart

#5 · Highest Capacity

5. Lucas Oil Stop Leak Gallon

• Weight: 3.56 kg
• Compatible with Vehicle Type: Car, Truck, Motorcycle
• Container Type: Bottle
• Size: 1 Gallon (128 oz)

Best for: Larger-volume mixed-oil option.

Why it ranks #5: The one-gallon, 128-ounce bottle is the largest listed engine-oil stop-leak format, although the supplied details do not explicitly confirm diesel use.

The one-gallon Lucas Oil bottle is the defining practical difference here, giving buyers a larger quantity of its engine oil stop-leak formula. It is compatible with petroleum, semi-synthetic, and full-synthetic motor oils, and the product claims to renew worn seals while reducing engine noise and oil consumption.

Lucas states that the formula renews worn seals without risk of damage or eventual corrosion, which makes seal condition its central target. Compatibility with three named motor-oil types lets buyers retain those oil choices while considering the treatment. The product also claims to reduce engine noise and oil consumption and raise oil pressure. Its gallon-size bottle is listed for cars, trucks, and motorcycles, making it relevant to buyers considering those vehicle types, though the supplied facts do not specifically identify diesel compatibility.

Skip it if you need stated diesel compatibility rather than broad motor-oil compatibility; Bar's Leaks OS-1 explicitly lists diesel engines.

Consider this Lucas option when the larger bottle and compatibility across named motor-oil types suit your maintenance needs. It lists several vehicle types, but diesel compatibility is not explicitly stated in the supplied product details.

Listed on Amazon as: Lucas Oil 10279 Engine Oil Stop Leak – 1 Gallon

#6

6. XADO ATOMEX Stop Leak

• Weight: 10.8 oz

Best for: Warm-engine seal-restoration routine.

Why it ranks #6: Its stated purpose is restoring elasticity in sealing materials, but its supplied compatibility details identify car engines rather than diesel specifically.

XADO Atomex calls for pouring its treatment into engine oil warmed to operating temperature, a specific step that shapes the maintenance routine. Its stated focus is restoring elasticity in sealing materials, making it relevant to buyers looking for an additive approach to oil leakage rather than a component replacement.

The product describes special components that restore elasticity in rubber seals and gaskets, linking its treatment to the materials it targets. The stated application step is to pour the bottle into the warmed-up engine oil tank, so this is a task for a time when the engine has reached operating temperature. The 250 ml bottle gives the treatment a defined volume, while the listed description does not establish compatibility with a particular fuel or oil type.

Skip it if you want an explicitly diesel-compatible treatment; BlueDevil 49499 lists compatibility with gasoline and diesel engines.

Choose this if restoring rubber-seal and gasket elasticity is your priority and you can follow its warmed-engine application step. The supplied facts do not specify diesel compatibility, so diesel owners should account for that limitation.

Listed on Amazon as: XADO ATOMEX Oil Additive Stop Leak Engine – Restore Seal and Gaskets, Treatment for Car Engine High Mileage or Rear Main Seal, Best Stopper Leaks Reseal (Bottle, 250 ml)

#7

7. Permatex Engine Oil Stop Leak

• Weight: 0.33 kg

Best for: No-dismantling oil-leak approach.

Why it ranks #7: It is specifically described as an engine-oil stop-leak product, but the supplied facts do not state diesel compatibility or a targeted seal location.

Permatex’s title states that its engine oil stop leak addresses oil leaks and burning without dismantling, making the no-teardown approach its clearest differentiator. The liquid comes in a 12-fluid-ounce size, giving buyers a defined amount to consider when evaluating a treatment intended to work through engine oil.

The title connects the product with stopping and preventing oil leaks and burning, while specifically stating that dismantling is not needed. That can matter to buyers seeking an additive-style approach rather than taking the engine apart for application. Its 12-fluid-ounce volume is clearly stated, and the listed material is rubber. The supplied details do not identify diesel compatibility, a specific application step, or a targeted seal location, so buyers should not infer those particulars from the product title alone.

Skip it if you need explicitly stated diesel compatibility and application instructions; BlueDevil 49499 lists diesel engines and an oil-sump or crankcase pour-in method.

This may suit buyers prioritizing an oil-treatment approach that the title says avoids dismantling and addresses both leaks and burning. Diesel owners should note that the supplied product facts do not explicitly state diesel compatibility.

Listed on Amazon as: Permatex 30302 Engine Oil – Stop Leak, 12 fl oz, Effectively Stops and Prevents Oil Leaks and Burning Without Needing to Dismantle

#8

8. Bar's Leaks Rear Main Seal Repair

• Weight: 1.1 lb
• Container Type: Bottle

Best for: Rear-main seal repair focus.

Why it ranks #8: It targets rear main, timing cover, and cam-seal leaks, but the supplied facts do not explicitly identify diesel compatibility.

Bar’s Leaks Rear Main Seal Repair specifically targets rear-main leaks while also naming timing-cover and cam-seal leaks. Its crankcase application fits an oil-change workflow: add the entire bottle where engine oil is added, at or between oil changes, without overfilling.

The product is specially focused on rear-main leaks but is also described as working on other engine-oil leaks, including timing-cover and cam seals. Adding the entire bottle to the crankcase at or between oil changes ties application to a familiar maintenance point. The directions say not to overfill, an important boundary when adding treatment. Bar’s Leaks states that most leaks stop within 100 miles or two days of driving, giving buyers a specific expectation rather than an immediate-result promise.

Skip it if you need a treatment with an explicitly listed diesel-engine application; Bar's Leaks OS-1 names diesel engines.

This suits owners focused on rear-main leaks who can add the full bottle to the crankcase during routine oil maintenance. Follow the no-overfill direction, and treat the stated timeframe as applying to most, not necessarily all, leaks.

Listed on Amazon as: Bar's Leaks Rear Main Seal Repair, 16.9 oz

#9

9. Liqui Moly Oil Leak Stop

• Weight: 0.27 kg
• Compatible with Vehicle Type: Car
• Container Type: Bottle
• Size: 300 ml

Best for: Rubber and plastic seal care.

Why it ranks #9: It addresses rubber and plastic engine seals and oil stains, but the listing specifies car compatibility and does not confirm diesel use.

Liqui Moly Oil Leak Stop names both rubber and plastic engine seals, including shaft seals and valve-stem seals, as its targets. That material and location detail helps buyers identify the treatment’s intended scope, while the description also links it to preventing oil stains beneath the vehicle.

The product says it regenerates rubber and plastic engine seals, specifically naming shaft seals and valve-stem seals. That targeting can help owners assess whether the described seal locations match their concern, rather than treating it as a general repair for every oil leak. The description also says it counteracts oil dilution and reduces engine noise and consumption through piston rings and valve guides. Its listed vehicle compatibility is car, and diesel compatibility is not specified in the supplied facts.

Skip it if you need an explicit diesel-engine listing; Bar's Leaks OS-1 names diesel compatibility and targets seals and gaskets.

This is a car-focused option for buyers whose concerns include shaft or valve-stem seals, oil stains, noise, or consumption. Its supplied compatibility does not explicitly cover diesel engines, so diesel owners should factor that boundary.

Listed on Amazon as: LM 1005 Oil Leak Stop 300 ml

#10

10. STP Diesel Oil Treatment

• Weight: 300 g
• Compatible with Vehicle Type: Truck
• Container Type: Bottle
• Size: 10.14 Fl Oz

Best for: Diesel oil viscosity treatment.

Why it ranks #10: Although intended for diesel engines, it is described as an oil treatment that increases viscosity, not as an engine-oil leak stopper.

STP identifies this as a diesel oil treatment whose additives increase oil viscosity, distinguishing it from products explicitly titled as stop-leak formulas. Its description also says it fights oxidation and breakdown and helps protect against wear, making it relevant to diesel owners considering broader oil support rather than a specifically stated seal repair.

The exclusive formula is described as reinforcing engine oil with additives that increase viscosity, which is the product’s clearest stated operating effect. STP also lists protection against engine wear and fighting oil oxidation and breakdown, giving diesel owners several oil-condition goals to weigh. The item is listed as compatible with trucks and comes in a 300 g size. The supplied facts do not explicitly claim that it seals leaks, so buyers seeking a named stop-leak action should treat that distinction seriously.

Skip it if you need a product explicitly described as sealing diesel-engine leaks; BlueDevil 49499 states diesel compatibility and leak sealing.

This suits diesel-truck owners seeking the stated viscosity, wear, and oxidation-related oil benefits. It is not explicitly presented as a leak-sealing treatment in the supplied details, so buyers with an active leak should account for that boundary.

Listed on Amazon as: Stp- 61300En 300Ml Oil Treatment For Diesel Engines