Coolant expansion reservoir . Sourcing.

[TactilePaul]

Looking for a top up coolant reservoir for Volvo md2030 we had the ‘through the radiator cap’ set up which was a disaster, have recently removed that and simply replaced it with the expansion relief cap , BUT , we don’t have enough expansion room and coolant is ejected from small brass pipe ( reason is that we still have the calorifier / cylinder flow and return that add extra volume of coolant )
I’m planning to add a clear plastic tank above cylinder and higher than engine plumbed into the return to engine but can not find a suitable product other than one from a car !
I think I may instead be able to simply take a hose from the small brass expansion pipe at radiator cap to a bottle ( any bottle as no pressure !) and that will hold expanded coolant until engine cools down at which point it will pull it back into engine ??
Any thoughts on this or where to find a small square coolant tank appreciated.
Thanks.

 

[DownWest]

Sounds like a car scrappy would have one.

 

[rogerthebodger]

I went to a ca scrap yard and got an expansion tank from a Mini. I fitted the pressure cap on the expansion tank and a non-pressure cap on the heat exchanger.

I also fitted an drain bottle to catch any rips from the expansion tank to keep the bilge clean

 

[TactilePaul]

I went to a ca scrap yard and got an expansion tank from a Mini. I fitted the pressure cap on the expansion tank and a non-pressure cap on the heat exchanger.

I also fitted an drain bottle to catch any rips from the expansion tank to keep the bilge clean

Thanks. Will do this I think. Cover both bases , I think that if you take the small hose to bottom of bottle it then sucks up any expanded coolant back into engine when it cools ? Having said that if you have a non pressure cap on the engine then how can any coolant get into your bottle ???

 

[billskip]

Thanks. Will do this I think. Cover both bases , I think that if you take the small hose to bottom of bottle it then sucks up any expanded coolant back into engine when it cools ? Having said that if you have a non pressure cap on the engine then how can any coolant get into your bottle ???

I think from reading your posts you need to understand the system a little better other wise you will end up chasing your tail.

 

[ithet]

I think I may instead be able to simply take a hose from the small brass expansion pipe at radiator cap to a bottle ( any bottle as no pressure !) and that will hold expanded coolant until engine cools down at which point it will pull it back into engine ??
Any thoughts on this or where to find a small square coolant tank appreciated.
Thanks.

That is exactly what I have done. A plastic drinks bottle cable tied to the side of the engine compartment.

 

[TactilePaul]

I think from reading your posts you need to understand the system a little better other wise you will end up chasing your tail.

why do you think i posted this request for help / info.?? if you have any , maybe any standard pressure setting for the PRV's integral to radiator caps, and or expansion bottle caps?, or the volume of expansion air:water ratio requirements for coolant systems? etc then why not share?,
If not then whats the point in telling someone whos looking for help/info that they should find some help/info...?.

 

[Bilgediver]

Are you fitting the correct tank caps in all the correct locations there are caps that just fit the top of the neck with no springs etc there are caps with springs which are non return and caps with springs which allow return.

The selection allows for either pressurised or non pressurised expansion tanks however the use of the wrong cap can cause problems.

Various expansion tanks are available from Amazon.

 

[billskip]

why do you think i posted this request for help / info.?? if you have any , maybe any standard pressure setting for the PRV's integral to radiator caps, and or expansion bottle caps?, or the volume of expansion air:water ratio requirements for coolant systems? etc then why not share?,
If not then whats the point in telling someone whos looking for help/info that they should find some help/info...?.

I obviously fully misunderstood your ability to solve your own problems.
However you have a system that once worked (possibly before you acquired it)
So it's not working satisfactory now.
The first problem is fluid weeping from the filling cap as I understand it. This could be due to several reasons but the one basic reason is the pressure is exceeding the cap working pressure, so the question is why, well now is when understanding the system will help you to resolve ite problem.
As I read your OP (I may have misunderstood) you commented on the possibility that extra cooling fluid was in the system due to a water clarifier.
This would make no difference at all, actually less water would be more of a problem.
So why is the water leaking by the cap?
Too much pressure? or faulty cap?or faulty cap seat?
Ok not cap or seat fault, pressure too high because temperature too high? pressure too high because fault due to head gasket? air in the system? restricted cooling efficiency? thermostat?
From you description of the problem as I understand it you need to go back to square one , because if there is a small fault it will possibly only get worse.
As for quoting all the technical data and info, will not solve your problem.
Your problem is there's too much pressure fault or the pressure relief device (rad cap) is at fault.

 

[Bodach na mara]

Normally in a car, there is a hose connecting the coolant circuit of the engine to the nozzle at the bottom of the reservoir. This hose is under pressure when the engine has heated up and can be teed off from any convenient hose in the circuit, such as the ones serving the calorifier, if your system has one. The filler cap on the engine, usually on the water cooled manifold, is a blank sealing cap. The pressure cap is on the reservoir. If there's a small pipe below the filler cap, this should be connected to the corresponding pipe at the top of the reservoir just under the pressure cap. This will also be under pressure. The alternative is to fit short blanking tubes to seal off these pipes.

Any car expansion tank can be used. I got a new one for a Corsa cheaply on Ebay. It is best to mount it more or less level with the engine filler for ease of refilling after the system has been drained.