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Model specific boards => Golf mk4 => Topic started by: J5H VW on 19 August 2008, 08:51
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Guys,
My air con compressor finally gave up the ghost and no longer runs at all....and I think that is what has caused the next issue that I experienced when stuck in traffic yesterday - overheating!
The car never goes above 90'C normally, however yesterday, it hit 125'c and was still climbing when i was stuck in traffic. In a brown pants moment, I put the heating on max temp, highest fan speed and opened all the windows in an attempt to get rid of some of the heat. It worked and slowly but surely, temp dropped back to 90'C.
When i got home, I checked out the fans in the engine bay - they are not running, and dont kick in even above 90'C.
I think this is liked to the compressor fault (or another issue) that might be causing this. Can anyone advise?
Is there a way to force fans to be on all the time? (as a temporary fix).
It only seems to over heat when standing in traffiic for more than about 5/10 mins - on the move its on, guess its due to the airflow into the engine bay when moving.
Is there a fuse or anything that I might need to check?
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in all honesty apart from your air con not working you could have a knackered water pump :sad:
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Anyway to test for that?
also, i figure that it even if the pump has packed up, the fans should still kick in right? And they are not doing so....
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If you have the air con compressor on then the fans should work at slow speed all the time - if this is not the case either then it does sound like they are cream crackered.
Check fuses, somehow check fans work at all(?), check slow speed (if you have air con)
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I know the fans should work at slow speed with air con on, but when I switch it on they dont run at all. However, I since the compressor does not kick in (as its now packed up), I am not sure if that is what is causing the fans not to work.
Basically, I am wondering if the fans are not working at all since the air con compressor has failed.
Does anyone know of a way to check if the fans are working without having to use the air con compressor?
Is there anyway to overiding the thermostat so that the fans run all the time when the car is on? If I could do that, I guess that proves the fans themself are ok.
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I know the fans should work at slow speed with air con on, but when I switch it on they dont run at all. However, I since the compressor does not kick in (as its now packed up), I am not sure if that is what is causing the fans not to work.
Basically, I am wondering if the fans are not working at all since the air con compressor has failed.
Does anyone know of a way to check if the fans are working without having to use the air con compressor?
Is there anyway to overiding the thermostat so that the fans run all the time when the car is on? If I could do that, I guess that proves the fans themself are ok.
On a MK2 if you supplied them with power they'd spin..
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Fan control unit is under the battery I think - somewhere around there, if you could find the main feed I am sure you could then test them.
Not a coolant sensor problem is it..? Not working so not reporting the temp to kick in the fans..? just a thought.
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in all honesty apart from your air con not working you could have a knackered water pump :sad:
good shout, thats what happened to me :laugh:
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Fan control unit is under the battery I think - somewhere around there, if you could find the main feed I am sure you could then test them.
Not a coolant sensor problem is it..? Not working so not reporting the temp to kick in the fans..? just a thought.
I dont think thats it, as the temp guage still works (and seems to behave as i would expect it to).
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I know very very little about cars, but i thought id offer what happened to my old Astra as a possible cause. Basically, the car was overheating and the fan wasnt coming on. The cause was a radiator switch which clicks the fan on when the water in the radiator hits a certain temp.
Could that be it??
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Maverick, thats what I am thinking the issue it - the switch (if one exists) that kicks the fans in at a certain coolant temp.
I just went and did a few more check over lunch. Guys take a look and let me know if you dont agree with that I have done/ what i beleive based on what i have done.
1. The Water Pump
To attempt to check this, I removed the coolant tank lid and started the engine. I can see coolant flowing back into the tank from the top hose when the car idles. I assume this shows that the pump is still working....so Water Pump is OK.
2. The Radiator
Next I wanted to check coolant was flowing round the whole system, and through the radiator. I let the car warm up and then touched the hose to the top right hand side (near the battery), as you look at the engine from the front of the car. I believe this to be the inlet to the radiator. It was now warm, so I assume coolant is flowing that far at least. To check it is coming out the other end of the radiator, i couldnt figure out which hose was the outlet, but the hose which feeds back into the expansion tank is now hot too (same one I used in checking the water pump). Given these two hoses are now hot, I assume the water is circulating right the way round the system, through the radiator.
3. The Fans
Next I need to check if the fans are working. I know they come on wtih the air con compressor, and run at low speed. My compressor has packed up, but I still turned the climate control such that it should be running. The fans are not running.
So...now...is there a fan switch, which causes the fan to kick in at a certain coolant temp? Where is this and how can I check it? I am pretty sure the fans are not broken, and it seems coincidental that I notice the overheat as soon as the compressor packs up and fans stop spinning.
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should have felt the bottom radiator house to see if the coolant is circulating. there is a thermostaic swith in the radiator on most cars you can bridge the 2 wires out and the fan will come on. if it doesnt you got a electrical fault to the fan, if it does the thermostaic switch is stuffed. i think the golf has a 3 pin switch so not sure which wires you need to bridge out. would need a wiring diagram from a haynes manual.
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Managed to find a local garage that was able check out the fan for me. Seems it the switch. Having it replaced tomorrow, so will see if it all works!
Cheers for all the help guys.
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Hi,
The air con will not work if the cooling fans or fan e.c.u has a fault, as the fan e.c.u also controls the air con compressor clutch.
On top of your battery is a fuse box, check ALL the fuses including the green 30 amp ones for dirty or burn't connectons as it is very common for this to burn out.
If it is burn't , you will need to change the fuse box assembly, not expensive, these fuses supply the fan e.c.u which then supplys the fans and air con.
Hope this helps?
Jochen.
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Get the triangle temp sensor off the rad and bridge two of the connections, do it one way and you'l get it on high fans and another on low, make sure you use thick wire as I did it and it melted it, then electrical tape the wires in, to turn it on and off take out the green fuse on the far left of you fuse bozx on top of your battery.
I got this problem too and it turns out that I need a new water pump fitted but it could also be the following: thermostat (get a 70 degree one instead), air lock in the system, empty all water and refill with coolant or the actual temp switch in the rad is knackered.
Any problems let me know as I am dealing with this atm on my motor.
Ashmond
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cheers for all the help guys.
The garage is replacing the temp sensor/switch on teh radiator today. Will see if that solves it. i think it a common thing for them to corrode from what i have heard.
Also, Jochen, it makes sense now that the air con compressor wont kick in since the fan switch is screwed.
Will keep you all posted on progress, collecting it after work - when it should have a new MOT too!
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I had 2 corsa's that were bad for this. It was the sensor called the thermo switch which senses water temp. to tell the fans when to come on. Not sure what they are called on the golf but could be the sensor or a possibility that your fan motor has packed in but very much doubt it.
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I know the fan motors work, as both spin when supplied with power (as applied with the switch removed). hence it suggests its the switch that is at fault.
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yep defo switch nice cheap repair for you :laugh:
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Garage called me. Still not too bad!
The swtich had to be replaced. But also there is a fan control unit/relay under the battery. That needed a good clean up (im guessing of the contacts etc).
Finally, a fuse above the battery had melted (though not blown). This had to be replaced too.
So all in all, turns out not too bad. not sure why the fuse started to melt rather than blow - will need to watch this one. Will check it out when I pick the car up.
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Garage called me. Still not too bad!
The swtich had to be replaced. But also there is a fan control unit/relay under the battery. That needed a good clean up (im guessing of the contacts etc).
Finally, a fuse above the battery had melted (though not blown). This had to be replaced too.
So all in all, turns out not too bad. not sure why the fuse started to melt rather than blow - will need to watch this one. Will check it out when I pick the car up.
Good news :cool:
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I know - im glad it was not the waterpump or something else!
It also flew through the MOT - shaking off the years and miles with relative ease.
I was getting a strong fuel smell inside the car, and they nice chap also said he has diagnosed that too - the pipe from the charcoal filter has a split in it and needs replacing.
Its great to have a decent mechanic local to you.
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it past the MOT with the smell of fuel inside the car :shocked:
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Yeah, you only smell it when the climate control fan is running! :huh:
Plus the guy knows what it is, its minor, and guess its not an issue. Go figure. :laugh:
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yeah strange one that, at least you know what it is though :smiley: