Evening folks.
On a sealed expansion tank type cooling system in a car, where should the inlet and outlet of the tank be plumbed into? I am thinking that the inlet
to the tank (i.e. fed into the top of the expansion tank) needs to go at a high point in the cooling system (such as the rad top hose).
The outlet from the expansion tank (i.e. at the bottom of the expansion tank) then needs to be fed into somewhere, but is this critical for correct
operation? I am thinking that perhaps the bottom hose from the rad would do the trick, but I'm not sure.
Secondly, is there a correct way to fill a cooling system from completely empty?
Cheers
Andy
I was asking the same at work. Have a Astra Expansion bottle wanting to plumb into Crossflow system.
Been advised i cant do what i planned.
So would depend on your engine etc.
I have a different approach that allows the tank to be low, you only have one pipe.
At the highest point in the cooling system take one small tube 1/4" ID, this is plumbed to the bottom of your header tank, thats it.
As water expands the header tank fills, as it cools the water is sucked back leaving air, you can now place this header tank anywhere.
My header tank is a bit of 2" ali tube, 8" long, bottom end capped with a standard rad cap on the top.
This is essentially the same system used on classic Range rovers, SD1 rovers etc, in these instances the header tank is plumbed off the top of the
rad, this has no eaxpansion top but a filling point.
Regards Mark
Regards Mark
quote:
Originally posted by mark chandler
I have a different approach that allows the tank to be low, you only have one pipe.
At the highest point in the cooling system take one small tube 1/4" ID, this is plumbed to the bottom of your header tank, thats it.
As water expands the header tank fills, as it cools the water is sucked back leaving air, you can now place this header tank anywhere.
My header tank is a bit of 2" ali tube, 8" long, bottom end capped with a standard rad cap on the top.
This is essentially the same system used on classic Range rovers, SD1 rovers etc, in these instances the header tank is plumbed off the top of the rad, this has no eaxpansion top but a filling point.
Regards Mark
Regards Mark
You have to fill at the high point, not the expansion tank, the point is that the tank can be low. On Range rovers, circa 89 - 93 you had an
additional filler which comes up by the middle of the plenum.
Where you have an inlet and outlet the tank must be high.
Okay, lets look at this another way take an older car with the expansion tank as part of the radiator, all we are doing is relocating the top part, by
using a small pipe you can bubble off the air.
This will fail unless you take the air out at the very top of the system, flow is unaffected, you must use a small diameter pipe, a large diameter
pipe will tend to try and act as the expansion tank itself.
[Edited on 20/11/07 by mark chandler]
How do you maintain the correct amount of air in the expansion tank?
There needs to be some air to be compressed when the water expands.
[Edited on 20/11/2007 by nitram38]
Make sure it is large enough, a RR tank holds around 1 pint, you need to ensure when cold and the water is drawn back the inlet pipe remains covered
or you will start pulling in air.
On my blade engine I get around 1/4 pints worth of expansion, you only partially fill the bottle.
[Edited on 20/11/07 by mark chandler]
quote:
Originally posted by mark chandler
Make sure it is large enough, a RR tank holds around 1 pint, you need to ensure when cold and the water is drawn back the inlet pipe remains covered or you will start pulling in air.
On my blade engine I get around 1/4 pints worth of expansion, you only partially fill the bottle.
[Edited on 20/11/07 by mark chandler]
Wouldn't the set up I suggested be less hassle?
All I did was fill it up and go. It is self bleeding and replenishes the water continuously, plus I don't have to unbolt it at the side of the
road if I have to refill the system.
It might be another tee and some extra pipe, but the maintenance time sure outweighs the extra install time.
I am using an expansion tank, which get fed from an outlet just below the filler/pressure cap. As the water expands in the system, it will be forced up the pipe into the tank as previously mentioned. If I have filled it too much with water, then some will be chucked out through the filler/pressure cap to give the correct pressure throuighour the system. It only has to do it once, then it will be correct level forever more! Simple.
Hi folks.
I have to admit, I do prefer the idea of a self bleeding, easy to fill up system, and the 2 pipe option seems to be best so far.
On the 4a-ge engine I have, there is an 8mm pipe connection on the hose going to the water pump inlet, and an 8mm connection on the hose coming from
the head (i.e. waterpump outlet, to rad top hose). I'm thinking that I could utilise these connections for a two pipe expansion tank, and save
the need for T pieces etc.
The connections were originally routed to the stock throttle body, but as I won't be using that, they were going to be blanked off.
Now, to find a suitable expansion tank!
Cheers
Andy
Hi all,
I had a look unde rthe engine cover of an MR2 yesterday evening, and the expansion tank is of the single pipe variety.
The overflow from the filler cap (in the top hose, near engine) is fed into the bottom of the tank (via the plain filler cap). There is a vent on the
top of the tank too.
I still prefer the two connection type though... 
Cheers
Andy
quote:
Originally posted by nitram38
Wouldn't the set up I suggested be less hassle?
All I did was fill it up and go. It is self bleeding and replenishes the water continuously, plus I don't have to unbolt it at the side of the road if I have to refill the system.
It might be another tee and some extra pipe, but the maintenance time sure outweighs the extra install time.