So I dig up the web to find the replacement; in short:
1) Radiator cap it a control valve that raises the boiling temperature point of the car cooling liquid keeping the coolant in liquid form under higher operating temperature.
2) 1.3 Bar (19 lbs) Cap: Valve open when coolant liquid hits 153 degC.
3) 1.1 Bar (16 lbs) Cap: Valve open at 127 degC.
4) 0.9 Bar (13 lbs) Cap: Valve open at 100 degC.
Naturally most people will choose to have the 1.3 Bar (as what I did before) which result that the coolant can still remain in liquid from at 153 degC (radiator + cooling system can operate at higher temperature before valve opens).
In actual condition of normal street driving (some short sprint) we rarely hit water temperatures above 120 degC. For track, it would be different story/game as we tend to push the car at the limit for long time. So for me, I downgraded the Cap from 1.3 Bar to 1.1 Bar.
Reason is:
1) I do not need my car cooling to work at 153 degC, if it does then the cooling system is need to be changed (Radiator, hose, water pump) to lower down the temperature (operating at high temp is NOT good for your engine due to possiblity of parts wearing to knocking issues).
2) The radiator cap does not help to improve the cooling rate of the system temperature, it only force the system to work at higher temperature.
3) The car cooling system efficiency improvement requires upgrade of High capacity Radiator, Silicon Tubes, Bigger water pump, better Fan + etc (basic items).
4) Very important... it is CHEAPER! :) LOL!
Note: Using a high pressure CAP in normal system and if the temperature ever hits above 140 degC; it would be a problem as the system is operating a over temp and component wear will be critical, the tubes may burst causing a disaster if you are pushing the car hard. Using a lower temp 1.1 Bar is safer as the raditor Cap only permits the system to be operated at max 127 degC.
(0.9 Bar is not really commended as it too close to normal operating temp, causing the valve to open too early and reduce the cooling capacity at normal use).
It is highly recommended to install an after market Water Temp meter to know exactly how hot is your engine coolant is running. (Below 100 degC is good, best at 90 degC but almost impossible to hit at hot days) (Above 100degC needs caution; and if it ever goes to 110~120 degC, it is better to slow down the car at "lower rev" and let the system cool)
12 comments:
I don't agree,
Don't believe everything you read on the internet
The manufactures didn't just "pick a number" for the .bar rating. Most motors these days are high performance, and sea level you should follow their recommendation.
The manufactures didn't just "pick a number" for the .bar rating. Most motors these days are high performance, and sea level you should follow their recommendation.
just try. no harm
just try. no harm
Inder choot piyo huma moot aur lund
The thermostat regulates the temp..not the cap..the cap keeps pressure in the system..coolant under pressure will handle more heat without boiling..u don't want to much pressure..follow manufacturers recommendations to be safe..
Anonymous, I disagree :-). In this case the thermostat does not regulate the temp, but regulates and maintains the flow thru the system. It's set to operate at a set temp. The cap on the other hand maintains the pressure in the System which controls the said temp. That is why there are different rated pressure rated caps. The pressure and temp relationship is important. The themostats job is only to try and maintain a constant temp thu out the engine by controlling the heat flow to the radiator by opening and closing as nessessary.
There is a los of stuff wrong on this post
Yes, most of the post and the replies are wrong.
The thermostat regulates flow of coolant at cold start, this helps to warm the engine faster.
The radiator cap on the other hand only regulates the maximum operating pressure, beyond which the cap relieves the system pressure avoiding further damage.
The true cooling system control is the engine computer via the coolant temperature sensors. One which acts as the fan switch. The fan switch is most important to keep the temperature under control and the fan in a cyclic on and off function.
A higher temperature thermostat opens later and keeps the temperature of the entire engine hotter. As soon as the temp falls lower, the thermostat closes and NOTHING circulates through the radiator. Most engines are set for very high temp with a 205F thermostat to help the engine meet CAFE (clean air fuel emissions) requirements at the cost of engine wear and tear due to higher temperatures throughout. Radiator caps are rated for a certain PSI or "BAR" at which they open and allow cooling system fluid expansion to be expelled into the overflow tank. When the expansion reduces due to engine cooling, a good radiator cap will allow the engine to suction liquid coolant from the overthrow tank. Understand that this back and forth flow restores oxygen into the water portion of the coolant and increases the corrosive nature of the water and the aging effect on the hoses and water pump. 50/50 solutions do not stop corrosion. They slow it down so the warranty expires before the cooling system requires repair/replacement. If you intend to keep your new car for 10 years and you have a five year loan and five year warranty, you should only top off the system with the proper 100% anti-freeze with an annual can of anti-rust and water pump lubricant. You should NEVER flush your system because it will restore the corrosive water back to its maximum corrosive ability and you should endeavor to reach a 70% anti-freeze and 30% water solution with anti-rust and water pump lubricant added at least semi-annually and annually the first few years. I have kept cars for 22 years, 15 years and 17 years and have never flushed the cooling system. Get the system up to 70% AF/30% Water with anti-rust and water pump lubricant and the radiator, water pump, thermostat and hoses will last a very long time. The 22 year old car had its original hoses when I sold it to an auto mechanic who was looking for an economical "beater" to drive back and forth to work. He couldn't get over that everything worked and the A/C and cooling system had never been repaired or serviced. The procedures I follow are the ones I learned from long haul truckers who own their rigs. They never flush their cooling systems and keep a 70%AF/30% water ratio. Don't believe anyone who tells you that water cools better. They wouldn't charge high end home boilers with anti-freeze if water transmitted heat better. Ethylene glycol and water solution works best and gets closer to the surface of metal parts than oxygen laden water alone that causes rust and scale which inhibit heat transfer. The reason that manufacturers do not use stronger solutions than 50/50 is because 50/40 costs less and gets the car past its warranty period. After that, the corrosion is YOUR PROBLEM.
Most of the information on this blog is inaccurate. Look elsewhere if you want accuracy.
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