GolfGTIforum.co.uk
Model specific boards => Golf mk3 => Topic started by: madsb on 24 April 2013, 20:09
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Hi guys.
Just fitted a new thermostat on my 8v and all the coolant was drained here. Put it all back together (why does it have to be so complicated to change a thermostat, VW?) and filled water in coolant bottle to flush system. Put heater control on max heat and turned on the engine. watched the temp rise to almost a 100 before turning off engine. Waited for coolant to cool and then took of the hose connected to the thermostat - but nothing came out. Also the air blowing from the fans was cold....
Being the complete noob I am, what can I do? Does this mean I have loads of air trapped in my coolant system or what? Or is the thermostat not working. Assuming the tstat is working (really don't wanna take it out again), what can I do? Would appreciate any pictures to go along, seeing as I'm a newbie :)
Cheers.
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Yes it does or you got damaged stat.
Should only get to 90, never above.
I massage top and bottom hose. Try to pump the water around the system.
Some people do get air locks but mine have always been fine.
Did you have this problem before the new stat?
Why did you replace it?
I'm thinking maybe the problem is a blockage in your heater matrix, but need more info
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Was the cooling fan cutting in mk3 engine barely holds in any trapped air its a fully vented system no bleed screws as far as i am aware what u need to do these checks start engine let it get warm then place your hand on the thermostat outlet hose if this is cold when temp is at 90 or more either you have fitted thermostat wrong eg round the wrong way or it is faulty now if your thermostat pipe is hot and your top rad hose that goes to the flange is cold u could have air traped in the rad or your rad internal structure has colapsed which is not allowing the flow of coolant also if all your pipes are hot including the heater matrix pipes check to see if your cooling fan is cuttin also u need to check if your water pump is working aswell if all pipes are cold it can indicate a knackerd water pump if your pump is not pumping all your pipes will be cold aswell so if you have put a new thermostat in and done it correctly this can also be a case of a faulty water pump try the above first to eliminate certain factors
Also to eliminate the new thermostat take it out get a bucket out boil water in the kettle pour it into the bucket place new thetmostat in if u can see through the top of the thermostat its opening if you done all the above pipes are cold thermostat is working as you checked its opening the water pump is not working
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The trick with this job is to have the heater on full and fill very slowly while squeezing the hoses, i got the missus to pour coolant in nice and slow while i kept squeezing and i've had no problems.
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I changed it as the oil would cool down from 90 to around 70 when driving and not just idling. The fan does not kick in now at any point. The only hose that seems to be cold is the one going to the tstat
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I changed it as the oil would cool down from 90 to around 70 when driving and not just idling. The fan does not kick in now at any point. The only hose that seems to be cold is the one going to the tstat
Knackered thermostat. At 90 that thermostat pipe should be warm, as the thermostat should open. If it's cold, it's fooked. Where did you buy it from?
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Tht dosent make much sense if thermostat pipe is cold all other should be cold as the thermostat is litterally near the water pump if that pipe is cold then youve got alot of air which i cant work out as i have changed my thermostat and i had no problems with air and i changed my cooling fan 3 days ago and didnt have any air blockage or youve got a faulty thermostat or a water pump but your previous symptons dont suggest water pump
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take coolant reservoir cap off...run the car...turn heater on full blast on hot...massage the hoses...you should get some air out if air is trapped...see if the bottom hose gets warm at 90...(try not to get it past 100) if not warm then thermostat is not opening for various reasons..fans should kick in at some point...
.anyways the water will start bubbling in the reservoir tank if your water pump is working.if not you might be very sad as water pumps don't last long when they are pumping air......which is a good reason to turn off the ignition...leave cap off of reservoir overnight and then check level in the morning...top up if needed..put reservoir cap on and then heat up car...if heater is blowing well and hot..then success! if not you may still have an air pocket..if heater is blowing poorly then maybe air pocket..maybe something else...
vw made the thermostat change very very difficult...(hence some people are scared to do it..like me...:)
by the way there is a valve in the coolant reservoir that is a one way valve that will let out fluid if needed...it is hidden under the plastic black thing on the side that says G11 (at least mine does) just open the cap when it is hot and quickly close it and you will see that fluid is coming out of somewhere.and will find it under the black thing...-not recommending that you do this..but they do have a fail safe to make sure the pressure does escape if it is excessive..
maybe you just put the thermostat in backwards???-I've learned to take pictures of everything if I am doing it the first time (or have pictures on hand of other guides which look exactly like mine..
Good luck!
Why don't you get someone to make a short video of your problem and put it up for people to see..
links FYI
http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/coolingmaint/index.htm
I like the picture of the thermostat...shows which way it should be put in...
may not need this,but for completeness..
http://forums.vwvortex.com/.php?5691585-Power-Steering-pump-removal-please-help&highlight=power+steering+pump+removal
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Thermostat is definitely fitted the right way. Which hose exactly is the top radiator hose? Will maybe make a vid today
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You cant miss it it goes to the big plastic housing into the head were the coolant temp sensor is
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to fit the thermostat on a 2.0 8v the wrong way round you'd need a hammer..... cos the flange won't go back on otherwise.
heater does not need to be on max. the matrix is ALWAYS in the loop. fill expansion tank with 1l water, then 1l coolant concentrate, then place cap back ON! start engine, kneed the bottom and top rad hose, rev engine from time to time a bit in short bursts (just pull the throttle cable on throttle body). when the coolant falls well below min turn engine off - open expnasion cover with care (if scared let it cool down a bit).... top up again.... replace cap... start engine kneed.... reapeat this it no longer goes below min...
now take it for a 5 mile spin.... when you come back allow to cool down and top it up again.
that should be it.... never had any issues when i did this.... (the reason you want the cap always on is to avoid the water boiling in the head => releasing gas)
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to fit the thermostat on a 2.0 8v the wrong way round you'd need a hammer..... cos the flange won't go back on otherwise.
heater does not need to be on max. the matrix is ALWAYS in the loop. fill expansion tank with 1l water, then 1l coolant concentrate, then place cap back ON! start engine, kneed the bottom and top rad hose, rev engine from time to time a bit in short bursts (just pull the throttle cable on throttle body). when the coolant falls well below min turn engine off - open expnasion cover with care (if scared let it cool down a bit).... top up again.... replace cap... start engine kneed.... reapeat this it no longer goes below min...
now take it for a 5 mile spin.... when you come back allow to cool down and top it up again.
that should be it.... never had any issues when i did this.... (the reason you want the cap always on is to avoid the water boiling in the head => releasing gas)
Thanks, great to have a step by step :) will take out the tstat and put it in a pan to see if it's actually working. Then I'll do this.
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Tried steps above (haven't tested tstat yet) and the bottom rad hose never got warm.... So I guess that the tstat is dead.. I'll take it out to verify.
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ALSO: There's no warm air coming out of the vents even when the coolant temp displays 90 degrees.... Is this also due to the tstat or what?
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Bottom hose only gets warm 1ce the temp needle is very close to half way. After that it gets very hot to touch.
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You got air lock mate. Sometimes its a cnut to get it out depends where the air is
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No hot air = worn out water pump.
Had same issue with a mates Saab. Car stopped giving out hot air, changed thermostat, still no air, took it out and tried it, still no hot air. Changed water pump. And we got hot air.
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No hot air = worn out water pump.
Had same issue with a mates Saab. Car stopped giving out hot air, changed thermostat, still no air, took it out and tried it, still no hot air. Changed water pump. And we got hot air.
Okay this is getting quite annoying.. Just tested thermostat, it works fine.. I really don't need a broken water pump atm....
How can I check if the water pump is broken? And how do I check to see it's not just air ? And how do I remove the air?? why didn't vw install a bleed valve.....
edit: also, there was hot air before taking it all apart
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have a look if you can see water coming out the thin hose that comes from flange and goes to expansion tank.
at slightly over idle you should see a fairly continuous stream of water coming out... if not check if its blocked.... if its not blocked your pump rotor and shaft are no longer joint together (happens with plastic rotors sometimes)
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They are still connected.. I have the pump out, and can see the rotor turn
This must leave air in the system as the only problem.... I tried massaging the upper and lower rad hoses with the engine running but to no avail.. there still wouldn't flow hot water into bottom rad hose.
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what rotor is it plastic or metal?
the plastic ones can come loose from the shaft, the pump still pumps a small amount round but only very little as rotor starts slipping more and more. hold the rotor and try to rotate the pulley. you shouldn't be albe to turn very far before your finger gets squeezed and then it should not slip. of course this is only a crude test.... but if you're putting too much force the blade will crack and braek off.
test the thermostat by boiling in kettle, if its not that i would go and get a new water pump.... they're only 25£ from gsf (thats their cheaper option but it had a metal rotor last time i bought one).
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tested the tstat, it was fine, gonna test the wpump as you prescribe when i get home
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what rotor is it plastic or metal?
the plastic ones can come loose from the shaft, the pump still pumps a small amount round but only very little as rotor starts slipping more and more. hold the rotor and try to rotate the pulley. you shouldn't be albe to turn very far before your finger gets squeezed and then it should not slip. of course this is only a crude test.... but if you're putting too much force the blade will crack and braek off.
test the thermostat by boiling in kettle, if its not that i would go and get a new water pump.... they're only 25£ from gsf (thats their cheaper option but it had a metal rotor last time i bought one).
Rotor is metal, and it doesn't slip when i try to make it... Will refit everything now and have another go at filling it up and not getting air trapped, assuming that is the problem.
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and make sure the belt goes the right way round the pulley.... on 1.8/2.0 you can put it the wrong way - which gives you issues....
should be driven by the ribbed side of belt, not the flat one.
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and make sure the belt goes the right way round the pulley.... on 1.8/2.0 you can put it the wrong way - which gives you issues....
should be driven by the ribbed side of belt, not the flat one.
of course hehe :) anyway, put everything together and going to fill it up again tomorrow to see if I can get it to work.
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Just run the engine on idle till it heats up reving that engine will spin the water pump faster making more bubbles in the coolant system let it just tick over till the thermostat is flowing and keep hot air low speed and then turn the heater fan speed up and then rev it up my prefered method it works on all cars as some cars can air lock if u rev it up my fav tool was the valeo vacum coolant system fill up tool works of a air line well handy
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okay some progress achieved I guess..
followed the following steps:
deattached lower radiator hose and took off coolant cap.
turned on the ignition.
filled in water until it started flowing out of bottom radiator hose (probably could have made it flow more)
turned on the engine with the coolant cap off and the level around max. also revved it occasionally.
So the progress now is that the bottom rad hose gets warm when tstat opens, which means theres less of an air problem there now...
bummer however is that the fans still won't put out hot air!! even when at 90 degrees..
How come? and what can I do to correct this? massaged the hoses while it was running. Also water pump is fine, could clearly see a reaction in coolant level when revving.
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why would you expect the fans to kick in at 90 already?
they come on much much later than that - 105 iirc
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why would you expect the fans to kick in at 90 already?
they come on much much later than that - 105 iirc
Read again dude!
He's talking about in car heater.
As I said at the start sounds like your heater matrix is blocked.
I would test this by disconnecting the two hoses and pressure flush it. Put a hose on the exit hose and try and flush it out or just see how well the water runs through the matrix.
If its fine then maybe the internal flap in the unit is broke.
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why would you expect the fans to kick in at 90 already?
they come on much much later than that - 105 iirc
Read again dude!
He's talking about in car heater.
As I said at the start sounds like your heater matrix is blocked.
I would test this by disconnecting the two hoses and pressure flush it. Put a hose on the exit hose and try and flush it out or just see how well the water runs through the matrix.
If its fine then maybe the internal flap in the unit is broke.
Nothing should be broken - heat worked fine before. Which hoses exactly? And where is the heater matrix and what does it look like? Noob in learning here :p
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matrix sits behind the dash. the two pipes are running into the bulkhead roughly where the clutch is, just behind the cylinder head.
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Would really love a picture if it wouldn't be a hassle - English is not my native language :) but I think I might know which hoses it is. They are on the side of the engine bay with the coolant bottle right? One of them got hot (the top one I think) when engine was warm, but the bottom one was cold, so guessing that's air and probably the problem too?
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lucky i happen to have a photo where they are on - just....
(http://imageshack.us/a/img833/4687/img20130422174911copy2.jpg)
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lucky i happen to have a photo where they are on - just....
(http://imageshack.us/a/img833/4687/img20130422174911copy2.jpg)
Awesome!! figured it might be those two, now I'm sure - thanks man. Gonna pull the cold one until water starts coming out :) hoping it'll fix it, as it did with the lower rad hose.
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Success! Heat is now coming out of fans :)
Anyway, for people with persistent air problems in coolant, this works for me:
Fill up and run engine with cap off while massaging hoses.
Turn off and let cool.
Remove bottom radiator hose (easiest to do by the end connected to the water pump)
Fill up until coolant comes out of bottom rad hose and then reattach it
Fill up until at an appropriate level
(next steps should be taken if no hot air is coming out from fans in dash):
Turn on the engine (from cold for safety) and remove the bottom or leftmost heater matrix hose from the bulkhead - it's the one that's cold even when the engine is warm
Rev the engine and pour in coolant so the coolant can fill the heater matrix
When coolant comes out of where the hose should be attached, reattach the hose.
Job done, fill up as necessary .
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:smiley:
Thought as such. Glad it's sorted