hi everyone.

can you please help me with this problem..

just finished restoring my car, passed mot drove it for about 10 miles, love it.

now everytime it gets warm( does not over heat) there is a bubbling noise coming from the header tank, now its sprang a leak.

before mot, i fitted a new low temp thermstat, new cossie fan switch and all new silicone hoses. the fan kicks in and cuts out when cooled.

have i got an air lock?
i ran it for 20 mins with cap off when all the above parts where fitted.

if so how do i bleed the cooling system?

if not any ideas what the problem is???

many thanks Ryan.

 

bubbling could be the coolant boiling, or it could be the head gasket gone or a similar problem!

Are you heaters blowing through hot, if they are its unlikely you have an air lock!

It'd be worthwhile checking the dipstick, inside the oil cap & rocker cover for signs of contamination, and likewise look in the coolant reservoir and look for signs of oil contamination.

 

there is no sign that the head gaskets gone, the temp guage is working and is reading low at all times.
when you remove the header tank cap and release the pressure.
it seems to be ok.
im really puzzled by this.
is the coolant not constantly boiling when up to temp?
could i have put too much water in, in the first place? the level now when hot is half way up my header tank.
thanks for the reply mate.

 

ideally the water should never boil, thats the whole theory behind having a thermostat and a cooling fan.

The only time you should hear/see bubbling in the header tank (IF at all) is just before the fan cuts in and it should clear almost instantly.

Too much water in the tank shouldn't really make any odd's it'll create a little more pressure in the tank but shouldn't promote boiling of any kind.

As ive said above aswell, do your heaters blow hot?

 

yes mate heaters blow hot.

 

unliekly to be an air lock then.........might be worthwhile having a compression test and/or pressure test carried out!

another thought....your water pump may be goosed!

 

when i bought the car 18 months ago, it had had a new hybrid turbo,head rebuild,piper cams and cam belt (not sure about water pump) it ran sweet up untill now. its got 69000 genuine miles.
i have fitted a front mount and kenlow in between rad and cooler and all new pipes.
i heard hissing from a pipe on the right hand side of the engine and now have a very small leak when up to temp on the left side.

i cant help but think that i have fitted or done somthing wrong some where

 

ps i have only done about 25 miles in whole time i have owned the car.

 

Is the small pipe from the top of the thermostat housing hot when the cars running?

 

i will have to check that tommorow night, why what you thinking??
cheers Ryan

 

the thermostat housing has a swirl pot in it, and the pipe on the top is like a breather pipe in effect, if it gets blocked it could cause a pressure build up. Also plays a part in the system bleeding itself.

And the connection on the top of the thermostat is common to rust away and block up.

 

ok i will check it tommorow.
cheers Ryan

 

My Cossie did this when I bought it. Turned out there was a small split in the header tank - this meant the system pressure was too low so the water boiled a touch.

Replaced it with a new one and it's been fine for the last two years

 

how much coolant - water did you use, idealy you wanted about 50/50 in the summer

 

checked the header tank today, and yes it is leaking. after close inspection it looks to have been welded/repaired at some time(bailey tank)
do you think its defo this thats causing the problems?
dont want to go and buy a new one if not needed.

ps sold my original one ages ago. gutted

 

get one from a scrap yard first befor u go bying a new one just to see if it sorts it any mk4 will do

 

okay sorry i aint steeling your post but i have the same problem but when i open the header i have shit loads of pressure(lots)then it starts 2 bubble,but when the cap is on i can here a hissing noise from the header when the engine is off

 

Your probably taking the cap off when its at boiling point, and if so your a fucking brave man

 

why?also i can hear bubbling water coming from the thermostat pipe(the thick 1)

 

cos to take a cap off when the systems at boiling point is just crazy?!

Best time to take the cap off is IMMEDIATELY AFTER the cooling fan has just run and turned off again.......

 

okay cool thanks for this but even when i dont open the cap i can hear the bubbling cuming from the thermstat pipe(thick 1)also a noise coming from the header,and this is with the bonnet shut thanks

 

When you turn it off?

Might just need a new cap if its not holding the pressure

 

okay put a new cap on it tonight went out in it for 20mins then home and still sounds like the water is boiling in the header why is this?i wasnt thrashing it,also the water in the header tank is 4cm below the cap when its boiling and the fan is on(after 20mins running?)but the gauge is reading half temp thanks for your help

 

have to start looking a bit more in depth now then

What car is it

 

its an s2 rs turbo,i think its the water pump but not sure.

 

Had this problem 2 days ago... after a bout 30 Min of driving in the hot Israeli summer, when I parked - the water boiled in the tank and it blew off the cap. Turned out to be a blockage in the upper thin pipe that returns the water to the tank.
I cleared it and had no boiling eggs since then...