10 bestCooling System Additivesof January 2026
112M consumers helped this year.
10% off
1
Wynn's Engine Oil Stop Leak Sealer Treatment Additive For All Engine Types 325ml & Car Radiator Stop Leak Sealant Antifreeze Coolant Repair Additive 325ml
Wynn's
9.8
2
AMK® Holts Radweld Plus 250ml Coolant Leak Repair Suitable for All Cars No Clogging Works in Whole System Permanent Non Damaging
AMK
9.6
3
Car Radiator & Hose Stop Leak Repair Additive Anti Corrosion 250ml Repairs Weld Cooling System Rads
ARZER
9.4
31% off
4
QuickFill - SEL9260: Central Heating Dosing Tool - Add Chemicals Like Fernox Central Heating Inhibitor, Sludge Remover, Leak Sealer & Sentinel X100 to Your Central Heating System
SPI
9.1
5
BRILLIANT, Yellow UV dye detector for A/C systems with R12, R134a, R1234yf, Hybrid & Electric Vehicles
ERRECOM
8.8
OtherUp to 16% off
Red Line (80204 Water Wetter - Coolant Additives - 12 Oz Bottle
LIQUI MOLY Pro-Line Radiator Stop Leak K | 250 ml | Cooler additive | SKU: 5178
LIQUI MOLY Radiator Cleaner | 300 ml | Cooler additive | SKU: 1804
ERRECOM Brilliant Coolant – 100 ml, Car Radiator Coolant Cooling System UV Leak Detector Dye
10% off
6
Wynn's Car Radiator Stop Leak Sealant Antifreeze Coolant Repair Additive 325ml
Wynn's
8.6
7
LIQUI MOLY Radiator Stop Leak | 150 ml | Cooler additive | SKU: 8956
Liqui Moly
8.3
8
LIQUI MOLY 5189 Pro-Line Radiator Cleaner 1 Litre - Black
Liqui Moly
8.0
9
Hydra PIC-24 Petrol Injector Cleaner and Carb Cleaner Additive, 500ml Treats 500 litres, With Petrol Cleaner you get more Petrol Power with Octane Booster Removes Deposits Improves Combustion
HYDRA
7.7
12% off
10
Holts Sealit Leak Repair 250ml, (Packing May Vary)
Holts
7.4
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