Loosing Water!

[james8iles]

Im losing water out of my coolant overflow bottle.

After driving its dripping out, im probably loosing about 200 ml everytime i drive.

First thought was the head gasket but i've had a sniff test done and nothing showed up, I havent done a compression test yet.

I have no overheating issues. 

The only other things I can think of is thermostat, fan switch or air in my radiator?

Has anyone else had any similar problems?

Thanks

[silverspeed]

Have you changed the rad cap?

[james8iles]

nope.  what difference would the radiator cap make?

[Chris_de_Bear]

With the car cold, try parking facing uphill or jack up the front then remove the radiator cap and top up the water. Run the engine and keep topping up as it warms up. The water will probably overflow a bit as it warms up. A few blips on the throttle will probably help. This should bleed the air out of the system as a starting point.

The expansion bottle shouldn't be full when cold or it will overflow. Also, make sure your overflow bottle cap is the right way round. You should be able to read the writing from the front of the car. It has 2 ports, the one that connects to the radiator should go to the long pipe down to the bottom, and the one that vents to air should be at the top.

[ChrisW]

nope.  what difference would the radiator cap make?

For want of a better term, if the rad cap is knackered then there's no pressure in the system and the liquid will flow out at a given, lower, pressure as the thermostat will not see an appropriate temp being reached. It happened to mine, swapped for a new cap and 'hey presto'

[Coyoteboy]

Yup, first guess would be the rad cap (assuming you're not over-filling the bottle in the first place). I too have replaced my rad cap to fix this issue, worked a treat.

[james8iles]

my fan never seems to come on either though? could this be due to this problem, or is it thermostat/fan switch related.

has anyone got info on how to bleed the system properly?

[Coyoteboy]

The fans rarely come on anyone in normal circumstances to be honest, you need to idle it for about 10 mins before the fan kicks in, but you can test your fan is operating properly by pulling off the sensor (bottom of the rad) - if the fan is OK it will fire up. It could be that your sensor has failed in the cold position but it's not that likely. Does your temp gauge in the dash move? it is desensitised around the middle area of the gauge, meaning that until it gets very hot you wont see the needle move from just below the middle.

Bleeding is done by parking the car on the flat and idling the engine with the rad cap off and the heater turned to hot but the fans off, once the fans have come on once or twice you can ensure its topped up and put the cap on.

Do you have a copy of the chiltons manual?

[james8iles]

the temp gauge does work but i had to fix it about 5 months ago as the sensor was making it work intimitently. 

ill have a go at bleeding it tomorrow. il check the fan is working too.

could it be the thermostat?

i have a manual for the st185, is this what you mean?

[Coyoteboy]

Technically a sticky stat could cause the water to boil and force it out, but its far more likel to be the rad cap to be honest, especially if youre not seeing overheating too. A new rad cap from Toyota is only a few squids and is your best first port of call IMO. Yup, I asked about the manual because I think the official bleed technique is in there but Ive not read it for a while and just gave you the way that works fine for me.

As said above, if the cap has a dodgy seal/spring it releases water too easily and the system never really gets up to pressure, meaning the water finds it easier to boil and expands into the expansion tank more easily.

Just make sure you're not over-filling the expansion tank, it's designed to allow expansion and contraction so it should not be full, it has max and min marks on it but they're often near impossible to see, I just bleed mine and ensure a  couple of inches of the tip of the expansion tank down-hose (the hose that comes down from the tank lid) dips into the water.