CAR Expansion tank cap
Coolant reservoir cap: common defects and their signs
- Corrosion and clogging of the cap valve.
- Efficiency of cooling system operation decreases.
- Level of cooling liquid in the expansion tank lowers.
- Smoke appears from under the hood.
- Coolant hoses are deformed.
- Smell of antifreeze is noticeable in the car passenger compartment.
- Valve jamming.
- Stains of antifreeze appear on coupling elements of the cooling system.
- Boiling of cooling liquid occurs.
- Antifreeze in the expansion tank quickly grows dark and cloudy.
- The expansion tank may inflate or blow up.
- Spring wear.
- Pressure in the cooling system increases.
- The passenger compartment warms up insufficiently during cold season.
- Antifreeze consumption increases.
How to replace coolant reservoir cap?
Manufacturers don’t indicate a specific lifetime limit for the coolant reservoir cap, so it is necessary to regularly check the component for mechanical damages. The part is not repairable, so it should be immediately replaced if any defect signs are found.
Procedure of car component replacement is quite simple, even a young driver can do it. One should be scrupulous about choosing a new component: the value of pressure at which the cap valve activates should strictly correspond to the same parameter of the broken-down part.
Basic sequence of steps for coolant reservoir cap replacement for any car is:
- Open the bonnet.
- Carefully unscrew the coolant reservoir cap.
- Clean the mounting seat of the cap.
- Install a new component and tighten it securely.
The work should only be performed after the engine cools down.

Expansion tank cap Information
Expansion tank cap: Bestsellers
- Pressure [bar]: 1,4
- Pressure [psi]: 20
- Supplementary Article / Supplementary Info: with gasket/seal
- Condition: New
- Pressure [bar]: 1,08
- Material: Plastic
- Colour: black
- Condition: New
- Required quantity: 1
- Pressure [bar]: 1,15
- Diameter [mm]: 53,6, 42,8
- Condition: New
- Colour: black
- Material: Plastic
- Opening Pressure [bar]: 2,1
- Condition: New
- Colour: black
- Pressure [bar]: 1,4
- Component Number: 038-027-002
- Condition: New
- Material: Plastic
- Opening Pressure [bar]: 1,1
- Weight [kg]: 0,036
- Condition: New
- Colour: blue
- Material: Plastic
- Opening Pressure [bar]: 1,5
- Condition: New
- Material: Plastic
- Supplementary Article / Supplementary Info: with gasket/seal
- Colour: blue
- Condition: New