I'm adding an expansion tank to my xFlow. Should the cap be pressurized or just a blanking off plate? The tank's the highest point of the
cooling system so I think it lets the water expand up the tank and then start blowing out the top? or should it have a pressurized cap which stops the
water from blowing out of the top?
Please can I get a recommendation for some decent tubing to connect my thermostat housing to my expansion tank, at the moment I've got some
scruffy stuff and I'm not sure what to google to buy new pipe. Any recommendations welcome. Cheers
Where's your pressure cap now?
If you are removing that and fitting the header tank as part of the cooling system you need a pressurised cap on the tank.
Have you considered a header tank system ? the rad filler is blocked with a flat cap ,the pressure car is on the header tank which is at the highest point of the cooling system with a pipe connection the lower pipe on the header to the return to the water pump elbow and a small hose connecting the rad overflow outlet to the top of the header. I've used this system on my car for years with no overheating problems .
Ah. I think I'm trying to fit a "header tank system"! My radiator has a pressure cap on it, from the top of my (fiesta) thermostat
housing I've got a pipe that goes into the bottom of my expansion bottle. The (uncapped) bottle fills up and overflows when the engine gets hot.
So it's here that I need to put a pressure cap rather than a blanking cap? Thanks
On my x flow engined car I use thin bore copper tubing run from front to the header tank on the bulkhead and then rubber vtubing to connect either end. I use 90 degree soldered connectors where necessary. I think the tubing is used for central heating installation.
This is my set up.
Radiator has no cap, you would blank yours off, pressure cap on a volvo header tank, chosen as it is rectangular. You can see the blue header cap,
orange funnel is in its place.
Small hose from rad to header joined using aluminium tubing.
And in case you are wondering, the thermostat housing was cut and rewelded to change angle of the outlet in order to connect to the alloy radiator.
The blue joiner is where the temperature sender lives.
[Edited on 16/6/18 by 02GF74]
quote:
Originally posted by timB
Ah. I think I'm trying to fit a "header tank system"! My radiator has a pressure cap on it, from the top of my (fiesta) thermostat housing I've got a pipe that goes into the bottom of my expansion bottle. The (uncapped) bottle fills up and overflows when the engine gets hot. So it's here that I need to put a pressure cap rather than a blanking cap? Thanks
@tin
your fiesta thermostat housing needs to have a pressure cap with 2 seals (and 2 valves) otherwise this open system does not work!!
during expansion valve 1 will open and let water expand into your "open" bottle..which could be even positioned on a lower level.
when the water cools down the created vacuum in the system will open valve 2 and sucks back the epxanded water from the bottle
important: the hose to te bottle needs to be connected on the bottom of the bottle or needs to be stuck inside the bottle until it reaches the
bottom.
your radiator needs a blanlking cap.
above system works bomb-prove...so you do not really need to change things...just a cap maybe.
hmmm, I've not quite got this yet.
I've got an ET above my fiesta thermostat housing. When the water gets hot it expands up the pipe to the ET and when it gets cold it contracts
back down. Is that good enough? that's better than the original isn't it where the water got hot and expanded onto the floor, then when it
cooled there was less water in the system? I've broken the tube off of my rad which used to connect to ET back in the day but that seemed to
work; then I had a "lotus" thermostat housing with a blank on it and a blank on my rad going to the ET with a pressure cap on it.
I need something functional at the moment, because I've got bigger fish to fry (no dash), once it's through the MOT I'll revisit this
with something better (new rad probably).
Cheers
@Alfas. I'd like the ET lower than the engine setup, but I've only got one pipe to play with (haven't we all...) at the moment; the one off of my thermostat housing.
I used the Dave Andrews design for my car: Oil & Water Control. Open the page, and look for 'Oil &
Water Control' in the menu.
Although I check the water level most times I have the bonnet off, I rarely have to top up - maybe once a year.
[Edited on 17/6/18 by David Jenkins]
i´m talking about such a thermostat housing. onto this you will fit the cap with the 2 seals...simlar such one:
[Edited on 17/6/18 by alfas]