When I saw a stuck thermostat to be fair was on a Fiat Punto. Hopefully its a far superior design, to the Fiat one

When I saw a stuck thermostat to be fair was on a Fiat Punto. Hopefully its a far superior design, to the Fiat one

 

Its done nr 150k, so can hardly complain about these type of items needing replacing. 

Indeed

It was (supposedly) about 40k on the Fiat with that trouble just to put into perspective ! That was after I'd already replaced the head gasket so I wasn't impressed but glad to find out at the time it was a false positive

 

Bloody awful car, but actually proved to be quite reliable once you understood the limitations of the cooling system and made a bloody cheap buy and runner for the wife until when I bought my vRS and she had my 1.4mpi !

 

For the fabia, certainly 150k to replace the stat or any such easily replaced ancillaries is a no brainer, no one should complain about if you compare to the above.

Indeed

It was (supposedly) about 40k on the Fiat with that trouble just to put into perspective ! That was after I'd already replaced the head gasket so I wasn't impressed but glad to find out at the time it was a false positive

 

Bloody awful car, but actually proved to be quite reliable once you understood the limitations of the cooling system and made a bloody cheap buy and runner for the wife until when I bought my vRS and she had my 1.4mpi !

 

For the fabia, certainly 150k to replace the stat or any such easily replaced ancillaries is a no brainer, no one should complain about if you compare to the above.

I actually considered a 1.9 diesel punto at the time i got the fabia. 

You changed the head bolts. before you changed the thermostat. 

Did the engine get new Coolant (Anti Freeze / Summer Coolant) by any chance?

Change thermostat! Bad parts I have read many places. 

I modified mine, and put in an standard thermostat. 1/8 of the price original.

I had to make new rubber sealing from an old inner tube form a bicycle.

i also use some sealant from a box. Permotex.

It is working good with no leak. 

 

Better solution I think! 

Ok i got a GATES thermostat, they are a reputable company, so hope its ok.

 

 - ive read people taking off the aux belt and alternator to get access to the thermostat, is that really required?

Ok half way there, cover is off... but thermostat is stuck in hard, do i just yank it out or is it twisted in?

They have a rubber seal on, its probably holding on with that.

stick a pair of pliers on it and pull it out.

Sorted, job done... how ever not as much coolant required as i would have thought. I flushed from tank> thermostat, then tank > temp sensor. I disconnected rad pipe top and flushed from top to bottom. Refilled not used 5 litre, just over 3 litres, ive take on a run, up to temp. I suspect i will need a few topups over the next few days, but not 2 litres worth.

Aslong as you've taken it for a slow run and got it up to temperature that should be most of the car filled up.

exactly as you say, a few top ups might be needed once a few air bubbles come back to the surface.

How can i overheat my car enough to test the radiator... no matter how long i leave it running, or hard i run it, it doesn't go over 90 :P

How can i overheat my car enough to test the radiator... no matter how long i leave it running, or hard i run it, it doesn't go over 90 :p

 

Wait until the summer :p

Wait until the summer :p

 

I can test the fan with wires from the battery, but that just tests that the fan works, not the mechanism to switch when it goes over 90. There must be a way :P

I can test the fan with wires from the battery, but that just tests that the fan works, not the mechanism to switch when it goes over 90. There must be a way :p

 

Maybe with VCDS?

Mines petrol but the only time I've ever heard the fan come on is in stationary traffic in hot weather.

Even if it does go over 90 the temp gauge won't show it until it gets well over 100C as it is weighted to show exactly 90 across a band of temperatures. The only way to actually tell is to look at VCDS.

And bear in mind too that the first  temperature that the radiator (dual) thermoswitch triggers at is 95C, I think, for low-speed fan action. The second stage, that gives the fan(s) full power isn't triggered 'til the temperature at the thermoswitch is 102C.  The thermoswitch is near the bottom of the radiator, so the coolant getting to it has already passed through the radiator before it even gets there.

Edited 5 March, 201610 yr by Wino

And bear in mind too that the first  temperature that the radiator (dual) thermoswitch triggers at is 95C, I think, for low-speed fan action. The second stage, that gives the fan(s) full power isn't triggered 'til the temperature at the thermoswitch is 102C.  The thermoswitch is near the bottom of the radiator, so the coolant getting to it has already passed through the radiator before it even gets there.

 That sounds about right. Basically its never going to happen with a diesel ticking over in the cold. Even in summer you would be waiting a while compared to testing it on a petrol

Ok i got a GATES thermostat, they are a reputable company, so hope its ok.

 

 - ive read people taking off the aux belt and alternator to get access to the thermostat, is that really required?

 

Gates are more than reputable, they make many OE parts for VW group cars, including cambelts.

Gates are more than reputable, they make many OE parts for VW group cars, including cambelts.

yes, im using their timing belts, aux belt and water pump

And bear in mind too that the first  temperature that the radiator (dual) thermoswitch triggers at is 95C, I think, for low-speed fan action. The second stage, that gives the fan(s) full power isn't triggered 'til the temperature at the thermoswitch is 102C.  The thermoswitch is near the bottom of the radiator, so the coolant getting to it has already passed through the radiator before it even gets there.

 

issue is what method is there to test radiator, and switches? my car is 12 years old and 145k miles, these things could well be in need of replacing. Im guessing that you would only get a fault code as and when the switch is required, and if its never going to get near 95c and 102c, not sure how it can be?

Not much to go wrong with the radiator, it's just a bunch of parallel pipes with cooling fins.

 

For the thermoswitch you could take it off the rad and test the first stage of operation in a pan of boiling water, whilst measuring resistance between pins 1 & 2. It should click and go from infinite resistance to zero resistance if it's working. You'd need to drain down the rad first of course.

Are the wires going to the thermoswitch thin or thicker? I think most Fabias have thin wires and use it as a signal to a control unit with relays inside, rather than switching the high currents to the fan(s) directly. Because of this, the contacts within the thermoswitch don't get worn out by arcing and sparking.

 

In other words, relax.

Not much to go wrong with the radiator, it's just a bunch of parallel pipes with cooling fins.

 

For the thermoswitch you could take it off the rad and test the first stage of operation in a pan of boiling water, whilst measuring resistance between pins 1 & 2. It should click and go from infinite resistance to zero resistance if it's working. You'd need to drain down the rad first of course.

Are the wires going to the thermoswitch thin or thicker? I think most Fabias have thin wires and use it as a signal to a control unit with relays inside, rather than switching the high currents to the fan(s) directly. Because of this, the contacts within the thermoswitch don't get worn out by arcing and sparking.

 

In other words, relax.

ok lol, am i right in saying that the 1st stage fan is used on a/c ? and yes the wire is thin, seems to go to the control unit  nr the front bumper passenger side, right nr the radiator drain tap.

Sorry Darkness, I missed this question. According to something I came across earlier while looking for something completely different ...

 

 

"It is also possible to test the radiator fan with

the self-diagnosis of the air conditioning

system."

 

 

Presumably that means if you go into the appropriate module in VCDS you can trigger the fan(s) and see them working (or not). Does your car have one or two rad fans?

 

Haven't tried it myself, but it looks like a useful trick.