Over heating help needed URGENT !!!!!

[mdh91]

Okay well recently the car started over heating and I originally thought it to be the water pump but water is still being pumped round so thought it was the radiator as the pipe going into the radiator was hot but the radiator and the pipe coming out was cold not even a little warm so changed the radiator now the pipe coming out is getting warm but not hot like the one goin in and the raditor is still stone cold :-s I hope it's not water pump but could it be a blockage in the system or something else like thermostat etc??

Help appreciated loads thanks Martyn

[mdh91]

Oh and it's 1.8t 20v aum engine I have

Thank you martyn

[itavaltalainen]

is water coming out the small hose that goes back to expansion tank?
which hose is getting hot? top one?

probably your thermostat not opening.... did you not try to flush radiator to see if it's blocked before replacing it.... i always try that first since it's FAR less work compared to the act of changing radiator....

[mdh91]

Yeah it's the top one getting hot and the small hose when I first disconnected coolant came out but left it off with engine running and nothing was flowing through and I didn't do a flush on old radiator before changing as it completely escaped my mind to try that :-/ but this is my first vw and my first golf so not that clued up on them

Thank you Martyn

[itavaltalainen]

try a new thermostat first IF you now have water coming out the small hose (should be a nice jet coming visible inside the expansion tank when it's connected and you rev it to 2k).

if you got no water coming out the small hose now it's probable the pump impeller and shaft have decided to split up... (quite often the case with plastic impeller pumps).

[mdh91]

Okay thank you for the help

Thank you Martyn

[mdh91]

Okay this morning moved the car onto the drive to check thermostat and replace if have to and I had only just turned car on and the temp gauge was reading nothing but warning light for coolant came on and started flashing so could it just be a faulty sensor? Or still just thermostat ?

[itavaltalainen]

when the top rad hose is hot and the bottom one isn't with car standing still then the coolant does not make it through the rad, otherwise the bottom hose should be almost as hot as the top (when engine is at 90 degrees) and the fans should kick in somewhere near 105..... if they are running e.g. cos you have aircon on the it can be normal that the bottom hose is fairly cold when it just sits there idling. the thermostat is not an on/off device but opens gradually with temperature.

the recent issue points towards sensor thou, this can be in addition to thermostat or a standalone issue. have you checked and compared temperature in the gauge on speedo and vcds to make sure they're showing about the same? although it is not unknown for these sensors to fail on mk4 engines. my neighbour had the same issue on his octavia. in his case the temperature in the gauge jumped up and down quite dramatically in an almost digital fashion.

[mdh91]

Okay well I'm starting to get baffled and annoyed now as changed thermostat cs took the old one out and dropped in some boiling water as I was told that's the way to test them and nothing happened so got a new one fitted and the system seems to have sprung a leak but my coolant is not going down :-s so now I am thinking water pump this whole thing is just confusing me and even tho the bottom pipe isn't hot there's pressure init like as if there is coolant in the pipe so I am just proper confused on the issue...... Anyway as I was typing this I had sum rad weld plus in and the leak seems to have stopped for now anyway :-/ but car still heatin up to about 115-120 mark and fans are kicking in and is cooling down slowly I'm stumped I really I am and thank you for all your input so far thank you greatflully and I hope I sort this out soon

[mdh91]

Okay cheers everybody for helping a vw newbie but after swapping everything I have come to the conclusion that it is defo water pump but thanks again for all the input