hi what would be the affects of the water tank not pressurizing?

like any other thing that doesn't hold pressure

it leaks.

but if you ask about physics I mentioned earlier I have some quotes (AUTOMOTIVE TECHNOLOGY - Principles, Diagnosis, and Service by James D. Halderman)

 

 

 

Cooling systems are pressurized to raise the boiling point of coolant. The boiling temperature will increase by approximately 3°F (1.6°C) for each pound of increase in pressure. At standard atmospheric pressure, water will boil at 212°F (100°C). With a 15 psi (100 kPa) pressure cap, water will boil at 257°F (125°C), which is a maximum operating temperature for an engine. The high coolant system temperature allows the engine to run at an efficient temperature and transfer more heat. Heat transfer by the cooling system is proportional to the temperature difference between the coolant and the outside air. 

NOTE: The proper operation of the pressure cap is especially important at high altitudes. The boiling point of water is lowered by about 1°F for every 550-foot increase in altitude. Therefore in Denver, Colorado (altitude 5,280 feet), the boiling point of water is about 202°F, and at the top of Pike’s Peak in Colorado (14,110 feet) water boils at 186°F. 

Working Better Under Pressure

A problem that sometimes occurs with a high-pressure cooling system involves the water pump. For the pump to function, the inlet side of the pump must have a lower pressure the outlet side. If inlet pressure is lowered too much, the coolant at the pump inlet can boil, producing vapor. The pump will then spin the coolant vapors and not pump coolant. This condition is called pump cavitation. Therefore, a radiator cap could be the cause of an overheating problem. A pump will not pump enough coolant if not kept under the proper pressure for preventing coolant vaporization. 

 

about cap colors: no difference.

btw to me traditional color = blue.

there are orange too.

no pink, sorry.

http://www.skoda-dily.cz/nahradni-dil/6u0121321-vicko-nadobky-chladici-kapaliny-cn-1498.html

like any other thing that doesn't hold pressure

it leaks.

but if you ask about physics I mentioned earlier I have some quotes (AUTOMOTIVE TECHNOLOGY - Principles, Diagnosis, and Service by James D. Halderman)

 

 

 

 

about cap colors: no difference.

btw to me traditional color = blue.

there are orange too.

no pink, sorry.

http://www.skoda-dily.cz/nahradni-dil/6u0121321-vicko-nadobky-chladici-kapaliny-cn-1498.html

 

Hmm thanks

 

i knew about the increase in boiling point just wondered if there was anything else hehe.

 

haha never saw an orange cap must be quite rare but thanks for clearing things up for me

 

I was wondering because i have just installed a thermostat on my 1.3mpi engine, drained the old coolant and poured the new engine coolant.

I bled the system and it works fine..  

 

The only problem is that when i drive the car from a cold start, the temperature gauge rises to about 100 then the thermostat opens and the gauge instantly drops to just below the half way mark ( so i guess about 75 - 80). It then keeps the temperature constant (just above the half way mark) and does not do it again.

 

The thermostat housing is the plastic version.

 

When i was bleeding the system from air,  i removed the temperature sensor and noticed that somehow the water stayed low until i either revved the engine or the thermostat opened at least once.

 

I might leave it since its keeping the engine at the right temperature but i was wondering what might be wrong because its not normal.

When i was bleeding the system from air,  i removed the temperature sensor and noticed that somehow the water stayed low until i either revved the engine or the thermostat opened at least once.

 

I might leave it since its keeping the engine at the right temperature but i was wondering what might be wrong because its not normal.

you bet it isn't normal.

to me it is an indication of:

- air pockets because you made a slight mistake when bleeding the system (see my method below)

OR

- the thermostat is catching, up to a point where the heat (T=110 C) makes it snap open suddenly.

 

here is how I do the filling and bleeding:

a) with engine cold and stopped I open the exp. tank cap

I remove the coolant temp. sensor

c) I start pouring the coolant into exp. tank

NOTE: at this point it helps a lot you didn't forget screwing back the drain screw...

d) when coolant start seeping from temp. sensor hole, I stop and squeeze hard 3 times the thick upper radiator hose

e) I pour some more coolant into exp. tank till only clear, no bubbles coolant seep  from temp. sensor hole

f) I put back the temp. sensor

g) I pour more coolant (if needed) to reach half way level between MIN and MAX and put back the exp. tank cap.

h) I start the engine and keep it run at idle or fast idle (1500-1800 rpm) till the fan kicks in.

i) I stop the engine, let it cool and refill again (if needed) to half way level.

 

never had a problem using this method.

 

i knew about the increase in boiling point just wondered if there was anything else hehe.

well... there is, but maybe you overlooked it.

I am sure not many forum members knew about the content of the paragraph titled Working Better Under Pressure.

I surely didn't prior reading the book.

you bet it isn't normal.

to me it is an indication of:

- air pockets because you made a slight mistake when bleeding the system (see my method below)

OR

- the thermostat is catching, up to a point where the heat (T=110 C) makes it snap open suddenly.

 

here is how I do the filling and bleeding:

a) with engine cold and stopped I open the exp. tank cap

I remove the coolant temp. sensor

c) I start pouring the coolant into exp. tank

NOTE: at this point it helps a lot you didn't forget screwing back the drain screw...

d) when coolant start seeping from temp. sensor hole, I stop and squeeze hard 3 times the thick upper radiator hose

e) I pour some more coolant into exp. tank till only clear, no bubbles coolant seep  from temp. sensor hole

f) I put back the temp. sensor

g) I pour more coolant (if needed) to reach half way level between MIN and MAX and put back the exp. tank cap.

h) I start the engine and keep it run at idle or fast idle (1500-1800 rpm) till the fan kicks in.

i) I stop the engine, let it cool and refill again (if needed) to half way level.

 

never had a problem using this method.

 

well... there is, but maybe you overlooked it.

I am sure not many forum members knew about the content of the paragraph titled Working Better Under Pressure.

I surely didn't prior reading the book.

 

Thanks for your very usefull information.

 

Now about how to bleed the system.

a to c i did as explained 

d) as far as i remember i did that but did not squeeze the upper hose pipe three times. i did squeeze after putting the sensor back though

 

i had started the engine after and let it bleed some more with the heater set to hot to bleed air from there too and i removed the temp sensor once again to let the air escape untill water was coming out.

 

Could it be that i have a small water pump? the engine is supposed to have a 6pk water pump but it has a 4pk one because i couldnt find.. i dont think that its the problem but you never know..

 

what i observed was that if i squeeze the upper hose pipe it feels like its pumping air/coolant and i see water pouring up from the bottom of the reservior tank.

 

The small water return also does not constantly feed water to the tank but only does so when the thermostat opens... i guess that further proves that the system has not bled correctly.

 

From what i have observed i am thinking that as the water heats up, the temperature sensor does not sense the water but instead senses the air which is hotter hence why it rises to 100.

After the thermostat opens, the water rises and hits the  temperature sensor and hence why i see it rapidly going down.

 

Other then that it does not do it any more until the engine cools down again... 

and the radiator fan turns on and off at the right temperature levels so i am not too worried about it

Edited 7 March, 201412 yr by warbuli

i had started the engine after and let it bleed some more with the heater set to hot to bleed air from there too

that is a common perception mistake.

water flows through matrix heater all the time, regardless of heater controls.

the heater control (cold <->hot) only moves air flaps (see figure) and it is not acting as a faucet for the matrix heater coolant circuit.

 

From what i have observed i am thinking that as the water heats up, the temperature sensor does not sense the water but instead senses the air which is hotter hence why it rises to 100.

After the thermostat opens, the water rises and hits the  temperature sensor and hence why i see it rapidly going down.

exactly that is the effect of air pockets.

if air is trapped under temp. sensor or if water pump size is a contributing factor, you have to further investigate yourself.