Header tank radiator cap

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stu60
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Header tank radiator cap

Post by stu60 »

Hi,
Can anyone please confirm the pressure rating and possibly make of the cap on the cylindrical header tank.

rover v8, my cap currently has 10 psi and tube which just vents to ground (hence you only fill header tank 50%).

I am having trouble bleeding air from coolant system. One of the problem is the standard thermostat housing points the hose up and over next to the distributor hence the top hose looks like it sits higher that the header cap tank. Has anyone found a solution?

I thought about seeing if the TVR E6037 straight thermostat housing might fit? Or maybe fit an Easybleeder coupling in the highest point of the hose?

Thanks
Stuart
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clive
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Re: Header tank radiator cap

Post by clive »

I can't tell you off hand what my cap is, but when I fill my system, I remove the top heater hose from the bulkhead, hold it up, and fill it through that until fluid comes out the heater matrix as it is the highest point.
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)
stu60
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Re: Header tank radiator cap

Post by stu60 »

hi Clive
thanks but i dont have heater just U bend joining valley manifold pipe so I don't think this is highest point on my installation
rgds Stuart
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peterc
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Re: Header tank radiator cap

Post by peterc »

Hi Stu,
At the time of building my Cobra with a Rover lump I was told I needed a different thermostat housing.
Part number AZ555 from Real Steel.
This kept the angle of the top hose down a bit.
My experience after numerous issues with air locks was to change the system for a closed one.
E.g. header tank full to the brim with a fixed cap. Overflow is then piped to an Austin Metro header tank mounted lower down which is kept 1/3 full of water. When the system heats up water is pushed out into the 2nd header tank instead of the road. When the engine cools down it sucks the water in the 2nd tank back in. No loss of coolant.
My main issue was keeping a water level above the top of the heater.
OK you haven’t got a heater but you still need to keep air away from anywhere other than the header tank.
Another member with a Rover chose to add a tank higher up on the bulkhead thus achieving the same higher level of water.
Hope that helps.
Peter C
stu60
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Re: Header tank radiator cap

Post by stu60 »

Hi Peter
thanks. i was thinking of making it a closed system and have sourced a Stag expansion tank which looks like it will do job. looking at Gerry's header tank i think the current overflow pipe will need welding/beefing up as it already weeps around joint which doesn't matter in current set-up but will in closed system.

i will have a look at the reel steel item. Thanks again
stuart
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peterc
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Re: Header tank radiator cap

Post by peterc »

Stuart,
On the Metro tank the in/outlet is at the bottom. This is important to get the water to be sucked back up.
Hopefully your Stag sourced item is the same.
Peter C
stu60
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Re: Header tank radiator cap

Post by stu60 »

Hi Peter
yes Stag is perfect it has inlet at bottom, you can see the water level. In have ordered the TVR straight housing as it looks like it will fit. I will update when it arrives!

thanks again for your help
stuart
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peterc
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Re: Header tank radiator cap

Post by peterc »

I guess it all depends on what top hose you have. My housing still angles up around 30 degrees but maybe is a slightly different orientation than standard. I can’t remember what th old one looked like as it’s a longtime since the 1999 build.
By the way I run a 15 psi cap.
Peter C
frats289
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Re: Header tank radiator cap

Post by frats289 »

A note of caution when using a Stag feed and expansion tank.
I went that route some time ago, the first one was ok for a year or so, then it leaked around the top where the copper joins the plastic. Rimmers were as good as gold and replaced it but then it split in the 3 hour queue for Le Mans last year.
I've now got a copper Metro/Allegro?? that I found somewhere and it seems to be working fine - not sure how it would perform in the same queue where the ambient air temp. in the shade was in the mid 30's.

Keep cool

Frank A
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Re: Header tank radiator cap

Post by Karl »

Brass expansion tank from the MG B, no problems since 10 years
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