How to tell if the thermostat opens?

[ThoughT ExperimenTs]

"With engine cold, remove radiator cap. Start car and watch the fluid level at radiator opening. When engine warms up the thermostat opens and the water level goes down because it's being released through the thermostat to circulate and cool the motor."
Is that right?

I thought I coudl just wait and see if the fan goes on?

[ThoughT ExperimenTs]

I left it for a few mins and came back and a lot had come out from where the cap is ment to be, it kept going up in down, I GUESS that means the thermostst works? Now just waiting for the fan.

[strap-on]

best way to do it is ull out your thermostat, and test in in hot water with a thermometer, check if its opening when its supposed to ( most thermoststas have the temp, stamped on the side)

[dragg_racer666]

take out your thermostat mate.
boil some water and then drop your thermostat in the boiling water. the water is very hot so the heat will make the thermostat open. if it dosn't open then it's buggered

[vvega]

soiulnds like you have a airlock ....it will pass

kepp adding water as it needs it

v

[ThoughT ExperimenTs]

well shit I didn;t keep adding water and I put the cap on and let it just sit there ideling, the engine temp gauge went jut over 3 quarters up and the fan still didn't go on? Please tell me that's because there isn't enough water?

[ThoughT ExperimenTs]

Sorry for the compleate newbie questiosn and panic. But I don't think the thermostat did ever open because the top tube was hotter then the bottem tube, the bottem tube was cold. I guess the engine only heated up because i didn't keep toping it up with water as it passed out all that air. The Fan I'm not really too sure about, maybe that's decided by the thermostat, and the radiator wasn't hot enough?

[vvega]

the bottom tube is water going into the engine the top tube is water comming out
if the bottom tube is cold the fan wont kick in and this as around where the thermoswitch is..
v

[ThoughT ExperimenTs]

I can't just keep topping up the water as it blurts it out, it just does big blurps and I can't put enough in, so I put the cap on again, the engine temp went 3 quarters up no fan came on, so i had to turn it all off again.

The thermoswitch is on the top tube, where the heater tubes are ment to connect.

3SFE engine, if that helps.

Somethings wrong.

[vvega]

no nothing wrong you just have a airlock
turn the carr off and add water for a bit
wten restart the car

airpockets are comon for a modern car best to have a proper rad filling vacume unit
great for this kind of isssue

v

[Mr Revhead]

you could try draining it and adding water slowly.....
i always run them with the cap off for a bit, then put it on drive round the block park it and let it cool the check. im paranoid so i always check the water (when cold) everyday fo rthe next couple.

[ThoughT ExperimenTs]

car is on a very slight slope - sloping backwards, should I jack it up a bit?

*waits for the engine to cool down again.*

[Mr Revhead]

what kind of car is it?
that shouldnt matter too much

[ThoughT ExperimenTs]

1990 Toyota Celica

[ThoughT ExperimenTs]

Ok it's working fine now, when it cools down again i'll let it run without the cap on so it can empty out a little more air and then i can add more coolent (because it will have like 90& water in there)

Thanks a lot vvega and everyone else for the help and advice

[edwagon]

make sure the bottom hose gets hot!!! that is how you check for thermostat opening, means that water is being circulated thru rad and out the bottom. The car isn't ok to drive until you are positive that the thermostat has opened and the bottom hose is hot to the touch. try rempving a heater hose or another hose near top of engine and making sure you have coolant at both side of the opening. you may need to get the engine hot, then let it cool down and let it bleed itself

[ThoughT ExperimenTs]

Yea the bottem hose went hot, the engine temp stayed at half way and the fan came on after a while. It's just because when I let it run without the cap it spilt out all the coolent

It's alright now, thanks

[Rob]

The reason that your car gets an airlock is beacause the air does not like to go down in the galleries. All you need to do is put a funnel in the radiator cap so it is higher than the engine and put the fan on high so the water can pass through as this is normallywhere the airlock is hanging out.
Also you can blled at the bottom of the throttle body if injected

[ThoughT ExperimenTs]

I actually have a feeling the headgasket has blown.

[[V8ROLA]]

top up the radiator, have car on angle so cap is higher than motor or as stated above (funnel), run motor and top up till its full, HAVE heater on hot setting you dont need the fans on as this will cause it to take longer to heat the water, just leave it running and kepping an eye on water level just top it up as needed and the thermostat should open just as the fans kick on.
and yes make sure both radiator hoses are hot.
also another way to rid air locks is to fill the resivour to the top and find a step hill and drive up it
and re-check the resivour tank when you get back and see if it used any water.