No Bananaraming Thermostat !

[Garp]

So yesterday we decided that, as my water hose was collapsed when cold, open when hot but not carrying water, it was clearly a case of dead thermostat.
Imagine my surprise today when I opened up to replace it and found nothing there !!!!!
This however now poses a question - We had thought that the hose was collapsing due to vacuum (which it would) due to the thermostat being stuck closed - with NO thermostat to be closed, I'm now a bit puzzled as to why no water is passing from the rad' into the water pump.
I've installed a new thermostat and gasket and all is fitted to dry overnight and I will see what crops up tomorrow, but now I'm thinking air in the system somewhere ????

[latil]

Collapsing hose is often a rad cap problem,run it with the cap off until hot then leave too cool,see if pipe collapses.

[Dave999]

people may think I'm talking rubbish

but in my opinion even if the stat fails open the restriction its support ring provides. provides a load to the pump which keeps it under higher pressure and stops cavitation.

without that I don't think the pumps work as well. so you could be boiling off and venting water vapour through the cap and then when it cools the vacuum pulls the cap seal in tight and then squashes the pipe.

unless you deliberately purchased a 2 way one you have a 1 way cap it vents out at its marked pressure but allows nothing back in

Dave

[70_charger]

Dave is right if the thermostat is removed the pump will not be as efficient , people don't realise you should NEVER run a pressurised coolant system without a thermostat OR a restrictor ring (looks like a big washer, or just outer body of stat) to give the pump something to push against. I'm sure you can get different size rings to give different coolant temps

[Adrian Worman]

people may think I'm talking rubbish

but in my opinion even if the stat fails open the restriction its support ring provides. provides a load to the pump which keeps it under higher pressure and stops cavitation.

without that I don't think the pumps work as well. so you could be boiling off and venting water vapour through the cap and then when it cools the vacuum pulls the cap seal in tight and then squashes the pipe.

unless you deliberately purchased a 2 way one you have a 1 way cap it vents out at its marked pressure but allows nothing back in

Dave

No Dave you are spot on
The system needs a restriction to keep the coolant flowing at a speed where its most efficient at removing temperature. If the coolant moves too fast it won't soak up the heat from the casting its trying to cool.

[Garp]

Right - so new thermostat is in and has dried and (hopefully) sealed overnight.
A possible clue to the collapsed hose is that my overflow tank ( square bottle linked by pipe to the top of the rad') is very very full at COOL, and after investigating it further is basically half full of "thick water" - kinda like wallpaper paste, clear/light blue ..... and the pipe is sucking from the bottom
I'm guessing that (perhaps, IMHO) upon cooling, when the rad' is sucking water back from this tank, the sludge is offering too much resistance, nothing flows and therefore a vacuum occurs in the hose ?
Obviously, this was all with no thermostat installed.

Todays task is to flush the overflow out totally and just top up to half as should be at cold then warm her up and see what occurs ....
If I've got something wrong here - please say so, don't want to do the wrong thing.
Thanks as ever for your insight
Garp

[Garp]

...... also, as I never had a thermostat before, and the pump wasn't pushing against anything, am I expecting more noise from the pump,
or more vibration ? or both ?
I'm guessing that if my pump is old and weak - now is when it will fail ?
Don't want to panic and start stripping stuff apart.
Thanks

[Dave81]

...... also, as I never had a thermostat before, and the pump wasn't pushing against anything, am I expecting more noise from the pump,
or more vibration ? or both ?
I'm guessing that if my pump is old and weak - now is when it will fail ?
Don't want to panic and start stripping stuff apart.
Thanks

Should be the opposite.
The pump has a curve to which it works most efficiently at. The restriction helps to maintain the optimum flow and efficiency (as stated above).
If the pump had been cavitating etc you would of heard it.............
I bet you you wont be able to hear it over the fan and V8 with the stat in now!!!

As for vibration and stress......again as you putting the pump back to where it should be in terms of back pressure....it should be more efficient which = less stress on components.

If its knackered, its knackered already, pre stat install............Time to test it!!

[Dart Vader]

It'll be fine, just start her up, let her get warm, clear the sludge (probably worth doing the whole system of course).

The water pump wasn't making any noises or grumbles particularly, but just a small wobble on the pulley.

These pumps are churned out in mass loads and although they will do the job its not like they make them to ultra exacting standards so a bit of wobble is probably ok

It'll be fine

If you need to borrow my rad cap to compare just let me know

J

[Bilko]

I had a collapsing top hose, changed the rad cap and it went away.

[Dave999]

just because you have a catch can or bottle doesn't mean it will ever suck anything back in you would need a special cap for that and finding one that does it that fits a 1960s radiator spout is hard work

catch can is just that catches what comes out so it doesn't make a mess.



if the water is thick. its either full of Radweld or two incompatible antifreezes


most of them mix but the bright red and the blue stuff tends to go a bit lumpy like clods of swafega.

it still works but its not ideal

Dave