Cooling Query

[dobboy 231 2 Cars]

Do any of you know for sure what coolong sensor is what from the 8v.

 

There is a long one which I got told on another thread was the coolant light, and the short one the gauge.

 

Is that 100% without doubt correct?

 

(I would have thought a sensor that gives variable resistance would have been the longer of the two.)

 

And what does the switch/wires do on expansion bottle lid?

 

Thanks

[Mattr5uk 20 5 Cars]

Am I correct that you've got the top right outlet of the expansion tank not connected? And is it out of that the waters pumping out of?

[Paul_13 212 1 Cars]

Like this

What's that off mate? looks different to the mi16 one I've seen

[Mattr5uk 20 5 Cars]

That's the metal bleed off pipe remove from the 8v thermostat housing then tapped into the Gti6 thermostat housing bleed screw hole.

If that makes sense?

[dobboy 231 2 Cars]

Yeah Matt, not connected, and it comes out that and the overflow, basically the expansion tank was bubbling.

[Daviewonder 533 3 Cars]

If you're not using it then you need to blank it off as the system wont pressurize.

[Mattr5uk 20 5 Cars]

I would block it off the system needs to be sealed. Im sure it will boil up quicker if the systems not pressured/sealed if I'm correct?

[dobboy 231 2 Cars]

I'll see what I can come up with to block it. But liquids boil quicker under pressure than at atmospheric pressure.

[Daviewonder 533 3 Cars]

No they don't.

[dobboy 231 2 Cars]

Your right, it's the opposite, the boiling point goes up as pressure increases.

Edited April 6, 2014 by dobboy

[dobboy 231 2 Cars]

Think i understand what's happening with it now.

 

Just looked on SBox and realised that the small normal relief pipe is up at the very neck of the bottle above the valve bit of the cap. The cap relief is set at 1bar on a 205...... I didn't even realise the caps had ratings or that there was a valve in there.

 

Because my other small pipe (spare) isn't sealed the system sits at atmospheric pressure and the boiling point is too low cos it can't pressurise itself as the engine/water heats up......the coolant/water is expanding hence spitting out (rather than increasing the boiling point through increased pressure..... and this is happening below the set point of my rad switch....... hence why no fan kicking in, and my temp gauge reading normal.

 

So hopefully, sealing the pipe and letting it all pressurise sorts it out, and the relief pipe should only have anything going through it at excess of 1bar....but by that time my fan set points should have been met at under 100deg , and my fan should have kicked in.... bringing the temp and pressure down (below 1bar)..

 

Eureka!

 

 

The switch on the lid of the bottle is for the coolant level warning light.

One sensor is for the low level (STOP light)...larger of the two 8V sensors

The other sensor is for the coolant temp gauge..... smaller of the two 8V sensors

[dobboy 231 2 Cars]

Blocked the spare pipe off and everything works perfect.

 

Thanks all.