Cooling Query

[dobboy 231 2 Cars]

Howdy, I've got the 16v up and running but not on the road yet but think I may have a problem with cooling.

 

Everything is plumbed up as normal and I used the 16v thermostat.

 

When idling for about 6 or 7 minutes my expansion tank overflow pipe starts spitting out boiling water but my fan hasn't kicked in.

 

I've checked the fan and wiring to it by shorting out the rad swich at the rad switch plug and its fine, and although I haven't checked the switch itself I don't see any reason for it to be faulty, but will check it if no-one has any other ideas.

 

The pipe from stat to top of rad feels warm, but not excessively so I assuming the stat is ok?

 

Anyone any ideas?

[welshpug 1,666]

Have you bled it yet?

[dobboy 231 2 Cars]

If by bled you mean loosened the little screw on the Tstat housing i did that the first time i filled it up, but haven't done it since, and i've added maybe 2 or 3 kettles full of water over the week when i've been turning it over.

 

Do i just loosen the little screw until water weeps out, then lock it off again?

 

 

I was more concerned that the 8V rad switch set point was too high?

 

Or should have used the 8v Tstat?

Edited April 5, 2014 by dobboy

[welshpug 1,666]

Bled the matrix?

 

Gti6 stat is lower than 8v, 83 vs 89.

[dobboy 231 2 Cars]

Thanks WP, no I haven't bled matrix.....

 

Good call.

 

Not even sure i can as I've used the 16v matrix pipes. I will need to do a bit of jiggery pokery.

[dobboy 231 2 Cars]

Just to add, the 8v sensors I used are reading normal when the water pisses out.

[omega 82]

but would not bleeding it stop the fan from from working?

[Miles 331 1 Cars]

205's rarely need bleeding, Fill up run for a minute and top up and job done, Hows the water system connected up?

[dobboy 231 2 Cars]

The water pipes are connected up as normal, with an additional t-piece into top matrix pipe from bottom of exp tank. Had it running today again, no issues, but still no fan. Gonna change the rad switch.

[Malc 45]

Dobboy as miles says, bleeding not an issue, is it piped up ok? If struggling let me know and il pop round to check out.

[dobboy 231 2 Cars]

Malc, yeah I'm sure it's piped up ok. I can feel the top and bottom rad pipes hot, and the fan runs when I bypass rad switch, so it's the only thing it can be...... I think.

[allanallen 528 2 Cars]

If by bled you mean loosened the little screw on the Tstat housing i did that the first time i filled it up, but haven't done it since, and i've added maybe 2 or 3 kettles full of water over the week when i've been turning it over.

 

Do i just loosen the little screw until water weeps out, then lock it off again?

 

 

I was more concerned that the 8V rad switch set point was too high?

 

Or should have used the 8v Tstat?

 

Right Dobby, I'm not being a twat but.... If you filled it and had the bleed screws undone how have you managed to put 2-3 kettles(4litres+) in afterwards? Where's it all going?

[dobboy 231 2 Cars]

Allen, the water was boiling and coming out overflow, I assume because the fan hadn't been coming on.

 

I've ran it various times, and when it's happened I've switched off..... And topped up the water.

[Mad Scientist 106]

I disagree with Miles on this. I find my car needs bleeding carefully, or it air locks and causes overheating.

 

Have you run the car with the expansion tank cap off?

[dobboy 231 2 Cars]

Yep mad. Have also massaged the pipes whilst its been running etc.

 

How do you bleed yours?

 

I've ordered a rad switch tonight, so will see how that goes when fitted.

 

Anyone know what the wires on the expansion bottle lid actually do?

Edited April 5, 2014 by dobboy

[Simes 248 2 Cars]

I've always filled up and bled with no need for the engine to run on the 205.

Never had an airlock. The expansion tank is the highest point.

[Mad Scientist 106]

I have to run mine with the cap off until the fan has kicked in at least twice. My coolant tank is mounted lower than standard, so I keep it filled. The level will rise, and it will overflow, unless you bung a bottle or funnel in it.

 

I run it until the level drops right back down again, then top it up and away you go.

[Mattr5uk 20 5 Cars]

Have you blocked off the top right hand expansion tank outlet/return or have you plumed that to top of thermostat housing bleed screw? That's what I've done on mine and fan cuts in as it should ATM. Defiantly advisable to do that if you haven't .

[Mattr5uk 20 5 Cars]

Like this

Edited April 5, 2014 by Mattr5uk

[dobboy 231 2 Cars]

Matt, no never blocked it off yet, just turned it into the bay and i thought its working as an overflow at the minute?

 

So on yours it's constantly bleeding it?

 

I'm convinced its my rad switch.

[dobboy 231 2 Cars]

Simes, even though the expansion tank is the highest point, the way the top matrix pipe bends down to join Tstat, I think there may still be potential for air lock on that pipe at the highest point,.....like a spirit level.

 

It doesn't help that I can't go on the road to try work any air out yet.

[welshpug 1,666]

Unlikely, should take a lot longer than 5 minutes idling to warm up let alone turn the fan on.

[dobboy 231 2 Cars]

WP, how can boiling water in exp tank be explained then? Surely the fan should have kicked in by then?

[Simes 248 2 Cars]

Simes, even though the expansion tank is the highest point, the way the top matrix pipe bends down to join Tstat, I think there may still be potential for air lock on that pipe at the highest point,.....like a spirit level.

 

Mines the same.

 

Have you tested the fan via the plug near the headlamp?

Have you tested the thermostat?

Have you recently replaced the expansion cap lid?

Have you bled the system using both bleed screws, matrix pipe and thermostat?

 

 

Mine spits water occasionally, I replaced the cap and it made it worse, so I reverted to the original one.

It should take around 10 minutes with the bonnet down for it to heat up for the fan to kick in.

[dobboy 231 2 Cars]

Dimes both rad pipes get hot, so I assume Tstat working. Tested fan, tested wiring to it, both ok.

 

Not tested switch but ordered a new one.

 

When I remove small upper left rad pipe it weeps, so rad is filled.

 

Same lid as before.

 

It's not blowing lots of mad hot water, but blows some water...... A puff of about a quarter of a mug at a time, every ten or so seconds.