I'm leaking! Water expansion tank in the engine bay for Murena 2.2

[Jon Weywadt]

Some feedback.... a picture paints a thousand words.
---
G.P.

Now you just need to make new straps in stainless steel like the ones I made. It is not difficult.

[Oetker]

Caution about the float level switches made from plastics.
The max heat is about 80 C degree (180F).
They get misformed easy.
Better is to go for RVS like this one.

http://cgi.ebay.co.uk/Curve-Water-Level-Sensor-Liquid-Float-Switch-Pool-Steel-/160504102042?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item255eca3c9a

[Anders Dinsen]

That's a very good point.

The particular one from CBS is rated up to 110 deg C and will probably accept more for brief periods without deformation, but note that the boiling point of the water in the tank is increased with pressure, so it could well be more than 100 deg over longer periods since pressure in the cooling system is well above 1 bar during normal operation.

But I'm not going to fit a level switch or sensor. It will not help detect boiling in the cylinder head as will happen when there's a small leak around the water pump for example: Initially the coolant level will increase and only after the water has stopped boiling will the level reduce. At that point the engine is probably damaged anyway.

/Anders

[Matra_Hans]

Hi
The water level sensor will give you an alarm on some kind of errors such as a leaking radiator (that killed my cylinder head) However I will like to combine the water level alarm with a high temperature alarm. The N9TE engines have a temperature sensor in the cylinder head that gives a "STOP" alarm at temperatures above 110 C.

Hans

[roy4matra]

That's a very good point.

The particular one from CBS is rated up to 110 deg C and will probably accept more for brief periods without deformation, but note that the boiling point of the water in the tank is increased with pressure, so it could well be more than 100 deg over longer periods since pressure in the cooling system is well above 1 bar during normal operation.

Two things wrong there Anders!  The temperature should not be above 100 degrees for ANY length of time and the pressure should not be above 85 kPa which is about 12 psi otherwise the pressure cap is not working correctly.

These systems should be kept below 98-100 degrees and if the thermostat and rad. switch are working correctly it should switch the fan in at 95 degrees, and even allowing for the distance between radiator and engine, the coolant should never exceed 100 degrees.  The minute the gauge shows anything like 100 degrees (sensor in the thermostat housing) you should switch off and find out why.

So that level switch rated for 110 degrees should be fine.

Roy

[Oetker]

Boiling point water at 12 psi pressure is around 117 C.
Beside the discussion if the water can reach this kind of temps in the expansion unit, I would never choose for plastics there.
Factory figures especial from Chinese fabrication are on the optimistic side.
80 C is the max.
This things are made for swimming pools gardening etc.
Don't let this beauty go cripple on this piece.
The RVS is not expencive compared to the plastic one.
Better save then sorry.

[Anders Dinsen]

Two things wrong there Anders!  The temperature should not be above 100 degrees for ANY length of time and the pressure should not be above 85 kPa which is about 12 psi otherwise the pressure cap is not working correctly.

These systems should be kept below 98-100 degrees and if the thermostat and rad. switch are working correctly it should switch the fan in at 95 degrees, and even allowing for the distance between radiator and engine, the coolant should never exceed 100 degrees.  The minute the gauge shows anything like 100 degrees (sensor in the thermostat housing) you should switch off and find out why.

Of course. Thank's for correcting me, Roy! Of course, I would never drive with the temperature sensor above 100 or even 90. I don't know what I was thinking about there?

The reason the system is under pressure is to avoid local boiling, which will take place even below 100 degrees if the pressure is not kept up. This is not something mysterical, but rather a phenomenon we all know from boiling water in a pot: There will be bubbles in the water long before the water has reached boiling temperature.

/Anders

[davidewanprice]

Any news on the finished product?

[davidewanprice]

Still no news on a final price? How many others are interested?

[GP]

Still no news on a final price? How many others are interested?

I only had interest in x 3 in total including yourself. I will pay them a visit and get a price for this number next week sometime.

G.P.

[Anders Dinsen]

Still no news on a final price? How many others are interested?

I only had interest in x 3 in total including yourself. I will pay them a visit and get a price for this number next week sometime.

Sounds good - I'm still interested!
As far as I can count we're 4: Jon, Hans, David and me.

[Matra_Hans]

Hi
I confirm my "order".
Hans

[davidewanprice]

Thanks for your efforts!

[GP]

I took my newly fabricated  (and tested O.K.) aluminium expansion tank and the original plastic one into Brise Fabrication yesterday and requested a quote for 5 x MK2 versions.

These will be a bit fuller in the body and with the correct size top outlet for the thermostat vent. Awaiting price and will advise soonest.

G.P.

[Jon Weywadt]

I took my newly fabricated  (and tested O.K.) aluminium expansion tank and the original plastic one into Brise Fabrication yesterday and requested a quote for 5 x MK2 versions.

These will be a bit fuller in the body and with the correct size top outlet for the thermostat vent. Awaiting price and will advise soonest.

G.P.

Outstanding. I'm stil on for one.

I am pretty sure that Philbert also wants one. Last I looked, his expansion tank looked like it was cracking too.