GolfGTIforum.co.uk
Model specific boards => Golf mk3 => Topic started by: Rmachines on 25 March 2008, 16:35
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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 :smiley:
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would check with vw, you dont want to blow your head gasket or warp your head!
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is the bottom hose still cold after doing it the secoond time? could b a block radiator.. also did the cooling fan cut in?
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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
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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 :smiley:
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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
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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
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might help
http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/coolingmaint/index.htm
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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. :angry:
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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?
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When filling the system - keep these general rules in mind:
Turn the heater on "full hot" -
The cooling system cap MUST remain "OFF" while filling, at no time should the system be subjected to pressure.
Don't let the car overheat.
Make sure the cooling fans are working.
Alternate the RPMs between 2500 and idle about every 30 seconds to force the air out of the system.
This process can take up to 20 min..
The heater should get hot. If the car is overheating, and the heater is COLD there is AIR trapped in the system. Turn the car off and let it cool down. Massage the upper hose. It should get hot. Once the car cools back down, start it again and keep filling. Some 2.0s seem to catch a lot of air. This is somewhat normal, and may take several cycles with a full empty system.
If the car is overheating, and the cooling fans are NOT working. Check to see that the thermo-switch in the radiator is hot. If its cold, the fans will never turn on, and the system has air trapped in it. If the switch is hot, make sure coolant has not dripped into the fan control unit (under the coolant bottle). A really dumb place for a piece of electrical equipment. Another trick is to turn on your A/C. This should also turn on the cooling fan.
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I have tryed all of that and its just not working!! Apparently they are a pain in the neck to bleed so i will have to find another way to do it.
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strange this because it would normally point to the thermo or a shot water pump. I've been reading a few other threads and a lot of people are going on about the header tank cap.....theres a regluator valve that can go inside the cap.... but if its boiling over with this off thats no help to you.
i would get it looked at by an expert...
please let us know what the outcome is :smiley:
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found a bit more info..apprently the bottom hose should stay cold at first then warm up after 5-10mins when thermo opens.. but from what i've found when it boils over let it run and it should work the air out slowly (BUT MAKE SURE YOU KEEP IT TOPPED UP WHILE DOING THIS)
http://www.golfgtiforum.co.uk/index.php?topic=27996.0
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Cheers, i had a word with my local garage and he knows his golfs! he said they are a pain in the ass!! but its almost certainly an air lock. SO ... i will go at it again tomorrow. Still VAG why didnt they put in a bleed nipple :rolleyes:
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Its just getting stupid now! i have tryed everything!!! It boils over at arround 100c and i have to switch the engine off!
I ran it up to 100 with the cap on and the whole system pressurised, but the bottom hose is always Stone cold!! Now if this never warms up the water will never get into the radiator and never cool!! So what can i do?? I have squeezed every pipe i can find and tryed empying it and refilling it twise! I have even manualy filled the radiator and squeezed out every bit of air i could! but nope! that bloody bottom pipe is always cold! :angry: :angry: :angry: :angry:
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Have you checked to make sure that the thermostat is in the correct way around?
It sounds like the thermostat was the problem initally, and now you've bodged it!
If all else fails, go back to the start and start again. Dismantle it, check it, then reassemble and re-bleed.
Kae.
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Hi, no its deffo in correctly! No reason why it wouldnt work now.
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any news on this rmachines?
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No nothing yet mate, still overheating! I have one other method to try which is to use a hose pipe and fill the engine block untill it comes out of the coolent bottle hose. Worth a go but i somehow doubt it will help :angry:
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hi im new to this site after recently purchasing a mk3 1.9d van "aka the can". I see in you post that is a while back that you have overheating probs and you symtoms are much the same as mine, I dont think that the hose at the bottom of the rad should be cold?
did you get to the bottom of why this was?... :huh:
cheers Towers
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Take the thermostat out and test it in boiling water to see if it opens. This is the only way to know for sure if its faulty.
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ok m8 il give that a try and il buy another new one and test it aswell!
cheers :cool:
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just take the thermostat out mate and run the car with out it in ,the car doesnt need 1 in just means the car will take longer to warm up :wink:
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it does need a thermostat, you risk engine damage over time as car will never get fully up to temp. plus it'll use more fuel as it will continuously be stuck in cold running loop.
if you're going to all the effort to take the stat out, its madness not to just put a new one in :rolleyes:
edit: oh and I've written up a coolant faq, its in the garage section. the bleeding method in there has never failed me ;)
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The one he is taking out is new. Testing it will confirm whether it works or not. If it works then youve saved a fiver! Also make sure you measure the water temp to determine that its opening at the right temp. I suspect the thermostat is fine though and you have head/ headgasket issue. :sick:
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Rmachines
any joy
i found this topic on a search
i am very curious to find out if you sorted it out as my newly acquired mk3 gti is doing exactly the same its pissin me off big time.
any news would be great
jay