Worrying issue

jackwoodcock

Guest
Today I went to town to grab some stuff to do my brakes, I drove back sensibly didn't give it any at all, when I got home I opened the bonnet and I could hear coolant bubbling? Water temp never goes over 90 or anything. Any ideas?
 

jackwoodcock

Guest
Ye levels all correct, il leave it running with cap off
 

wildrides

Active Member
Dec 27, 2013
396
1
Thermostat may be stuck shut or the plastic impeller on the water pump has started spinning on its shaft or broken up entirely in bits ........... this causes localised boiling as no circulation
 
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wildrides

Active Member
Dec 27, 2013
396
1
The water gets hot and bubbles as no circulation as pump cant pump . Causes hot spots but not where temp sender is so does not always show on temp guage on short runs .
 

wildrides

Active Member
Dec 27, 2013
396
1
err yes ............ On cupra R can change both pump and thermo externally ........ easy

on cupra thermo is external ....... pump behind cam belt ........ more involved ........ buy a golf MK IV haynes manual ( blue one ) or visit a garage if not capable of doing yourself
 

jackwoodcock

Guest
err yes ............ On cupra R can change both pump and thermo externally ........ easy

on cupra thermo is external ....... pump behind cam belt ........ more involved ........ buy a golf MK IV haynes manual ( blue one ) or visit a garage if not capable of doing yourself


Any checks I can do for either so I don't just go changing parts for no reason
 

Azza_

Active Member
Sep 17, 2008
526
2
South Shields
could also be the expansion tank cap not sealing, if it doesnt get upto pressure the coolant boils.

possibly a simple check would be to get the car upto temp and crack the cap you should get a hiss of pressure, BE CAREFULL NOT TO REMOVE IT FULLY AS PAIN AND SUFFERING WILL OCCUR
 
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