Overheating!!!

[Rmachines]

Hello, My GTI has been over heating since i took the radiator off,  Now... i ran the system with the top off the bottle to bleed out air, and all of a sudden it bubbled up and it errupted!! Coolent everywhere.  I Toped it back up and gave all the hoses a squeeze and i noticed the bottom radiator hose was stone cold, allthough the others are absoultly boiling!!!  I squeezed the hoses untill i felt water in it, so as far as i can tell, the pipes have coolent in them, not sure about the rad though!  i ran the engine again and sure enough it boiled over,  i put the cap back on and ran it and it hit 110c so i stoped the engine!!  the fan didnt kick in so i guess the water in the rad is still cool!  the fan deffo works!

Whats it mean when the bottom is cold?  usualy i would say an air lock but i dont see how to bleed the system?

Cheers

[BobbyT]

would check with vw, you dont want to blow your head gasket or warp your head!

[fitkin]

is the bottom hose still cold after doing it the secoond time? could b a block radiator.. also did the cooling fan cut in?

[nelds]

when u did rad did u completly empty stsyem or just remove top and bottom hoses..??.....did u take hoses off engine block..?.....i just squeezed the hoses with filler cap off until all air was expelled. when a compression check was done mine still drips from water pump connections but other than that all went ok

[mush]

I had the same thing with my old mk2. I don’t know if its the same on the mk3 but the thermo sits in the end of the bottom pipe that connects to the water pump

I couldn’t work it out at first, all pipes were under a lot of pressure where as the bottom was cold and didn’t seem to get warm even under normal running temp.

anyway in the end it was the thermo that had seized up and not opening and closing correctly infact when I removed it I tried it in some boiling water and not a sausage.

new thermo in running fine again but sadly I drove it around a week before I sorted it so my headgasket did go   :cry:£300 to repair for one stupid £5 thermo.

anyway don’t take my word for it I’m not an expert and it could be down to something else but do get it in asap   

[Rmachines]

Hi i will look into where the thermostat is, the cooling fan did cut in but that was when it was well into 100c,  i guess the water in the rad must have just reached 80 or what ever it cuts in at while the water in the block was boiling up

[Paul86S2]

It took a long time to bleed the air out of mine.
Try filling it up put the cap on the expansion tank, then run the car, stop at 90 or 100 degrees, let it cool down then top it up.
Repeat 2 or 3 times until all bled.
Top rh corner of rad was the last place to be bled of air, which is where the thermo switch for the fan is, hence why my fan wouldn't cut in until the system was fully bled.

Cheers

Paul

[mush]

might help

http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/coolingmaint/index.htm

[Rmachines]

Hi i have just changed my thermostat.. but still no change!  the bottom rad hose is COLD!! and with the top off the coolent bottle it hits 90c ish and boils over! But still,  the bottom rad hose is cold ?!  The water pump is working because i can see it being circulated and dipping when the engine is reved.  Does this mean there MUST be air in the system still?  and if so how the hell do i get it out?


Cheers. 

[mush]

are you sure theres no blockage anywhere?... hmmmm interesting. sounds like everythings working as it should. did you follow that link on bleeding the system?