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Best Steel Seal - Holiday Sale

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Last Updated - 16.12.2025

Best Choice

01

STEEL SEAL

Steel Seal, Easy Repair of Defective Cylinder Head Gaskets, The Original With Improved Formula

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9.7

Exceptional

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Main highlights

The original with improved formula: effect is now more permanent – repairs all types of cooling water leaks in the engine, such as leaking head gasket, distorted cylinder head or cracked engine block.
Recommended dosage: Engine capacity up to 2.5 litres = 1 bottle. Engine capacity from 2.5 to 4.0 litres = 2 bottles. Cylinder capacity over 4.0 litres = 3 bottles.
Protects the cooling system: unlike other "radiator sealants", Steel Seal is free from fillers (fibres, granules, etc.) and thus prevents unwanted deposits in the cooling circuit. Due to the unique action (thermochemical bonding process), the repair remains permanently after successful application on the cylinder head gasket.
Easy to use without dismantling. No tools required. Detailed step-by-step instructions for correct handling of the product included (English language not guaranteed). You will also receive "Additional instructions for combustion pressure in the cooling system" and other helpful tips for lasting results (English language not guaranteed).
Compatible with all water-cooled engines (cars, trucks, buses, SUVs, tractors, etc.) and commercially available water-based antifreeze (no concentrate, extended or long-life coolants).

89,99 €
Value for Money

02

K-Seal

KALIMEX LTD K-Seal K5516 Coolant Leak Repair

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9.6

Exceptional

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

No flushing. Just shake, pour and go.
Multi-purpose single-stage permanent
Item Package Dimension:1.9 " L x 4.25 " W x 7.6 " H
Can be mixed with all types of antifreeze

33,95 €
03

Bars

Bars Bar's Cylinder Head Gasket Sealant and Repair Additive 600ml Head Gasket

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9.4

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Universal product
Premium class
Car Cleaning & Care

22,99 €
04

K-Seal

KALIMEX LTD KSEAL Coolant Leak Repair

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9.3

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

No rinsing necessary. Just shake, pour and you're done.
Multi-purpose one step and permanent.
Can be mixed with all types of antifreeze.

17,00 €
05

STEEL SEAL

STEEL SEAL TESTCHEM Cylinder Head Gasket Tester CO2 Cooling Water 100 ml - Cooling System Exhaust Gas Test Car - Test Kit for Head Gasket Test Before Use Universal for Cars, Trucks & Water-Cooled

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9.0

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

No tools and previous knowledge - Complete test kit for immediate use - no tools, no previous knowledge, no removal required.
Ideal preparation for STEEL SEAL - The CO2 test gives you confidence whether Steel Seal can be used sensibly on your vehicle (product sold separately).
For all water-cooled engines - Suitable for petrol and diesel engines, cars, vans and minibuses - ideal for quick diagnosis of white smoke or pressure in the cooling system.
Fast self-test - Within a few minutes you get precise results: the test fluid changes colour as soon as CO2 is detected - quickly and reliably.
Easy CO2 seal test - Carry out the test for cylinder head gasket damage conveniently yourself. Test fluid shows CO2 in the cooling system by colour changing.

16,82 €
06

RELD

Reld Cylinder Head Gasket Tester, CO2 Leak and Coolant Check, Universal, for All Cars and Motorcycles, Cylinder Head Gasket CO2 Leak Tester, Rapid Engine Leak Detector, for 50 Tests

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8.9

Very Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

- Thanks to the universal adapter with a large measuring range (25 - 55 mm), you can check cars, trucks, tractors, excavators, motorcycles and forklifts among others.
- Quick, cheap and above all without having to visit a mechanic, you can check whether the cylinder head or the seal under the head in your car is fully functional.
- Original cylinder head seal tester from the renowned brand "Reld".
- Made in the European Union. With 99.9% efficiency!
- If you suspect a seal defect under the cylinder head or in the cylinder head itself, you can check the error yourself and save time and money.

23,99 €
07

Power Maxed

Power Maxed Concentrated Radiator Conditioner 325 ml - Cooling System Cleaner Against Deposits, Limescale & Rust - Radiator Cleaner for All Vehicles & Coolants

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8.7

Very Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Regenerates seals and metals - Maintains porous seals and metallic surfaces in the cooling system and prevents premature wear.
REMOVES HARTNESS DEPOSITS - Dissolves radiator sludge, oil residue, rust and limescale throughout the cooling circuit and restores full function.
Protects components and materials - The radiator cleaner works thoroughly, protects hoses, seals, thermostat, water pump and connections.
POWER MAXED – INNOVATION FOR YOUR VEHICLE – Highly effective additives, cleaners and care products – developed for maximum performance and long service life since 2009.
Easy to use without removal: fill the cleaner directly, let the engine run while standing, empty - without tools or workshop.

13,79 €
08

Liqui Moly

LIQUI MOLY Pro-Line Radiator Sealant K | 250 ml | Radiator Additive | Item No.: 5178, Rosso

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8.5

Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Suitable for aluminium coolers
Permanently and reliably seals hair cracks and minor leaks
No negative side effects on water pump and heating circuit
For preventive use
Compatible with standard cooling water refiners and antifreeze agents

13,45 €
09

MATHY

MATHY - DropStop Gasket Additive (250 ml) - Oil Additive Stops Oil Loss in Engine, Gearbox, Rear Axles & Power Steering - Regenerates Seals

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8.4

Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Stops oil loss - By adding Mathy DropStop oil additive to the engine or transmission oil, leaking and age-brittle shaft seals / seals become soft and swell again.
Saves expensive repair costs - To achieve maximum effect, DropStop should remain in the oil for as long as possible. It can be mixed with all engine and transmission oils. Can be used at any time.
Quality from Germany - MATHY is a German premium manufacturer with over 80 years of experience in the development of additives and engine oils. The products are produced in Germany.
Perfect protection: intact seals are maintained by the oil additive. It is particularly suitable for preventive use on vehicles and machines older than 5 years.
Easy to use - The DropStop seal additive is simply added to the engine or transmission oil in a mixing ratio of 1:16. Not suitable for engines with timing belts running in the oil bath

31,55 €
10

Sinofort

Sinofort Pack of 180 EPDM sealing washers, 304 stainless steel seal, M8/M6.3/M5.5/M4.8/M4.2, galvanised sealing washers, washers with neoprene seal, for electrical appliances, industrial machinery

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8.2

Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Wide application: these EPDM seal are smooth, hard and thick. The washers are used when attaching sheet metal profiles, roof elements and wall covers. They are good for drilling screws and are often used in electrical appliances, industrial machinery, residential construction and residential construction.
Stainless steel, galvanised, EPDM rubber: the metal part of the EPDM sealing disc (M4.8 x 1.4 / m4.2 x 12 / M8 x 25 / M8 x 22) is made of high-quality 304 stainless steel, EPDM sealing disc (M5.5 x 16/M5.5 x 19/6.3 x 16/M6. .3*25 /M6.3 x 19) The metal part is made of galvanised material with high hardness, smooth surface without scratches, corrosion resistance and rust resistance, on the neoprene side made of neoprene EPDM, high and low temperature resistant, acid and alkali resistant, UV resistant and durable.
Seal construction: washers 304 stainless steel combined with EPDM, improve the fastening effect as well as the function of sealing, insulation of water and air, preventing leaks. Prevents thermal expansion and shrinkage during installation issues during the period that helps solve problems with vibration noise and acts as a shock absorber. Perfect for saltwater, fresh water, wet environments and other wood related projects.
Easy to use: the washers with the seal are simply placed on the screw and the screw tightened, making sure that the seal fits snugly to the flat surface. The seal has a curved shape and when tightened displaces the air from the screw and flat surface, the rubber fits snugly against the flat surface and forms an airtight seal.
180 pieces EPDM sealing washers: the pack contains 30 pieces M4.2 x 12, 30 pieces M4.8 x 14, 10 pieces M8 x 22, 10 pieces M8 x 25 304 stainless steel seal, 20 pieces M5.5 x 16, 10 pieces M5.5 x 19, 50. pieces pieces M6.3 *16, 10 pieces M6.3 x 19, 10 pieces M6.3 x 25 galvanised seal and 1 transparent plastic box. A total of 180 pieces EPDM sealing washers, assorted in a transparent box. Different materials and sizes so you can choose the right seal washer according to your needs.

9,99 €