The importance of a radiator pressure cap can’t be measured through the size of the valve.
Despite being a smaller mechanical device, the radiator pressure cap keeps the engine safe from extreme conditions.
By keeping the coolant pressure and temperature in check, the radiator pressure cap retains the engine’s cooling system’s efficiency for a long time.
Before we understand what a radiator pressure cap is and how it functions, it is important to have some basic knowledge about the engine’s cooling system.
What is the engine’s cooling system?
The cooling system of an engine is the mechanical process that helps in keeping the temperature of the engine within its optimal range.
While generating power for the pistons to move up and down continuously inside the engine’s cylinder chamber, the engine generates heat simultaneously.
Some of the heat is carried away by the exhaust gases through the exhaust valve.
The remaining heat however is consumed by the engine itself. As a result, the engine gets heated as well when generating power.
To bring back the temperature within its normal range, the engine’s coolant system plays an important role.
The coolant used in the engine’s cooling system absorbs that excessive heat to bring back the engine’s temperature within its optimal range.
How does the engine’s cooling system work?
The parts of an engine’s cooling system are-
- Water pump (pumps coolant around the cylinder chamber from the lower radiator tank)
- Fan (helps the coolant temperature to pass to the air)
- Water pump (pumps the coolant)
- Coolant reservoir (collects the coolant)
- Thermostat (prevent coolant flow to the radiator unless the temperate of the coolant reaches a certain level)
- Heater core (transfers the heat from the coolant to the air)
- Radiator pressure cap (reduces the coolant pressure and temperature)
- Necessary plumbings
The coolant flows from the lower radiator tank to the engine block, then towards the cylinder head, and finally towards the outlet for the radiator.
The function of the coolant here is to absorb the heat coming out from the cylinders so that the engine block does not get overheated.
The radiator pressure cap opens only when the temperature and the pressure of the coolant go over the normal range.
Otherwise, the coolant moves downwards to the radiator.
While flowing downwards, the coolant loses its heat to the air flowing past the space between the flat tubes.
The fan connected to the radiator here increases the temperature transfer rate.
The cooled-down coolant finally reaches the lower radiator tank from where the coolant again circulates back to the engine’s block.
What is a radiator pressure cap?
A radiator pressure cap is a mechanical device connected to the radiator that lowers the pressure and temperature of the coolant passing through the radiator.
Principles behind a radiator pressure cap?
Higher temperature builds higher pressure. When the coolant enters the upper radiator tank, the excessive heat increases the coolant pressure.
Excessive pressure then opens up the radiator pressure valve.
The coolant then passes through the radiator pressure valve until the temperature comes down to the appropriate level.
The cooled-down coolant then passes to the overflow tank from where the coolant again returns to the engine chamber.
How does a radiator pressure cap work?
An internal combustion engine’s radiator pressure valve is usually designed to open at 15psi.
While passing through the radiator, if the pressure of the coolant goes above 15psi, the radiator pressure cap opens, allowing the heated coolant to pass through the radiator pressure valve.
At such a juncture, coolant passes both through the upper and lower parts of the radiator.
As a result, the pace of the coolant flow remains in the optimal range.
Major benefits of having a radiator pressure cap
A radiator cap might be cheap, but it is the most overlooked item of any internal combustion engine’s cooling system.
Here are the top five benefits of a radiator pressure cap-
- A radiator pressure valve protects the engine from overheating.
- The device aids the radiator in functioning properly.
- The radiator cap transports the coolant to the coolant reservoir from where the coolant again goes back to the radiator for recirculation. As a result, the coolant always stays at a proper level.
- The radiator cap prevents air from getting inside the coolant system.
- Finally, the radiator pressure cap allows the coolant to expand and contract to prevent any vulnerabilities inside the cooling system.
In a nutshell, a radiator pressure cap ensures that the cooling system of an internal combustion engine keeps running even if the temperature level of the coolant goes up.
What can happen if a radiator pressure cap is damaged?
A faulty radiator pressure cap can cause the following problems inside an engine’s cooling system-
- Coolant leak
- Radiator overflow
- Radiator hose may damage
- Air will intervene in the cooling system
- Overheated engine
- The level of the coolant will drop
Remedies of the radiator pressure cap and cooling system problems
1. Coolant leak
Lose hose clamp
Tighten the hose clamp
Repairing the radiator
Damaged water pump
Sealing water pump or changing the packing
Lose core hole plug
Replace with a new plug
2. Internal leakage
Faulty head gasket
Change the faulty gasket
Broken head valve compartment
Change the head
Broken valve port
Replacing the head or block
Broken push rod compartment
Changing the block
Changing the block
Leak in the oil cooler
Repairing or replacing the oil cooler
3. Weak coolant flow
Low coolant level
Need to fillup the radiator to the right level
Broken radiator hose
Oily or loose fan belt
Replacing or tightening the fan belt
Air leaks through the bottom hose
Need to place the hose clamp in the previous position
Lose or broken impeller
Need to change the impeller assembly
Blocked radiator water passage
Reverse flushing the radiator or cleaning
Closed engine water jacket
Reverse flush or cleaning the cooling system
4. Engine overheating
Low coolant level
Fill up to the right level
Blocked radiator air passage
Cleaning the air passage by contracting the air pressure
Incorrect ignition timing
Correcting the ignition timing
Low lube oil level in the engine chamber
Need to add lube oil until it reaches the right level
Faulty valve timing
Correcting the valve timing
Faulty radiator pressure cap
Radiator pressure cap replacement
Need to melt the frosted coolant using an antifreeze solution
5. Radiator overflow
Adjust the coolant to the right level
Flush the cooling system and add essential additives
Air leaks through the bottom part of the radiator
Reposition the hose clamp to its earlier position
Damaged head gasket
Replacing the head gasket
6. Low engine temperature
Replacing the thermostat
Faulty temperature gauge
Replace the gauge
Faulty temperature unit
Replacing the temperature unit
7. Noisy water pump
Replacing the sealing or lubricating the system
Changing the bearing or pump assembly
8. Water freezing
Use anti-freeze solution
Not using any anti-freeze solution
Use antifreeze solution
Add new solution
9. Dirt in the cooling system
Using dirt water
Need to use clean water
Lube oil or grease intervene in the cooling system when the head gasket is damaged
Changing the gasket
Damaged water-bearing, shaft seal, or gasket
Replacing the water pump kit
Radiator pressure cap
From preventing airflow inside the cooling system to keeping the coolant in place, the radiator cap does a lot of good deeds to keep the engine chamber wholesome.
The size of the radiator cap might be smaller, but the device does help an internal combustion engine to function properly.
Last Updated on July 21, 2022 by sajjad