Colin Davies Posted November 5, 2023 Report Share Posted November 5, 2023 Has anyone tried or fitted an expansion tank to the GT6 2 litre cooling system. If so did it improve the cooling system? Colin Link to comment Share on other sites More sharing options...
JohnD Posted November 5, 2023 Report Share Posted November 5, 2023 Not a GT6, but SofS with 2.6L engine has one, really because the Honda radiator has provision for one in the filler neck. Small volumes of coolant might otherwise escape, as the coolant itself expands slightly, and small bubbles even more so. Certainly the expansion bottle needs topping up now and then. John Link to comment Share on other sites More sharing options...
johny Posted November 5, 2023 Report Share Posted November 5, 2023 I reckon Colin is talking about a sealed system like a modern. Has been done but not easy as has to be mounted at highest point and really the radiator cap needs blanking off plus a large connection hose run to the expansion tank so that filling is done from that and doesnt take ages.... Link to comment Share on other sites More sharing options...
SpitFire6 Posted November 15, 2023 Report Share Posted November 15, 2023 Hi, Have fitted an expansion tank to my "GT6". No more air in the system as the coolant level above the thermostat housing. Never needs topping up as expansion space is more than enough with a 20PSI cap. the ali tank is wider than the height. Works 100% better than OEM overflow bottle as Air is never cycled into the coolant. Cheers, Iain. Link to comment Share on other sites More sharing options...
Ian Foster Posted November 15, 2023 Report Share Posted November 15, 2023 (edited) Iain Sounds interesting. Could you post some pictures please. Ian Edited November 15, 2023 by Ian Foster update Link to comment Share on other sites More sharing options...
SpitFire6 Posted November 15, 2023 Report Share Posted November 15, 2023 1 hour ago, Ian Foster said: Iain Sounds interesting. Could you post some pictures please. Ian I will tomorrow from work. Cheers, Iain. Link to comment Share on other sites More sharing options...
Steve P Posted November 16, 2023 Report Share Posted November 16, 2023 I have one on my 2.5 Vitesse. Alloy tank mounted next to the master cylinders, top outlet via a pipe to a tapping in the thermostat housing and bottom outlet via the manifold. No need for the expansion bottle. S Link to comment Share on other sites More sharing options...
johny Posted November 16, 2023 Report Share Posted November 16, 2023 Do you fill via the tank or still use the rad cap? Link to comment Share on other sites More sharing options...
Steve P Posted November 16, 2023 Report Share Posted November 16, 2023 Tank S Link to comment Share on other sites More sharing options...
SpitFire6 Posted November 16, 2023 Report Share Posted November 16, 2023 Link to comment Share on other sites More sharing options...
Ian Foster Posted November 17, 2023 Report Share Posted November 17, 2023 Iain Thanks for posting the photos. What radiator is that? Seems you have managed to get it vertical, whereas several I have seen have had to slope it forwards to get clearance. You don't show an overhead photo at the front, but I assume you have bleed pipe from the thermostat housing to the tank. I think I can see where it comes into the top of the tank. Ian Link to comment Share on other sites More sharing options...
SpitFire6 Posted November 21, 2023 Report Share Posted November 21, 2023 On 17/11/2023 at 15:01, Ian Foster said: Iain Thanks for posting the photos. What radiator is that? Seems you have managed to get it vertical, whereas several I have seen have had to slope it forwards to get clearance. You don't show an overhead photo at the front, but I assume you have bleed pipe from the thermostat housing to the tank. I think I can see where it comes into the top of the tank. Ian Greetings, belated reply. It's a Golf GTI mk1/2 radiator. <£40 new eBay. All alloy ones are available wider. Not worth the money. plastic and aluminium is cheap. ran for a year with only the hoses and two ruberised holes in the chassis. Cheers, Iain. 1 Link to comment Share on other sites More sharing options...
johny Posted November 22, 2023 Report Share Posted November 22, 2023 Out of interest how do you work out what level of coolant to fill the header tank to? Too little air and the expansion of the coolant on heating will raise pressure enough to lift the cap while too little and the pressure wont be high enough to stop the coolant boiling in the hottest areas... Link to comment Share on other sites More sharing options...
SpitFire6 Posted November 22, 2023 Report Share Posted November 22, 2023 Hi, I assumed 6L and 5% expansion. Needed over 300mL of space above the highest level in the tank. Found the tank in scrap at work. It was off an EV. Somebody must have wanted to bling the truck. Was easy to fit, unlike the plastic ones I had bought. The highest level in the system is the tank 1/2 full. Air bleed on top of the thermostat housing removes any air from the engine's highest point. Cheers, Iain. Link to comment Share on other sites More sharing options...
johny Posted November 22, 2023 Report Share Posted November 22, 2023 yes think thats the only way to calculate it. Otherwise brim tank and it will expel excess coolant on heating to draw air back in when cooling and the cold level is then what should be maintained? Link to comment Share on other sites More sharing options...
SpitFire6 Posted November 23, 2023 Report Share Posted November 23, 2023 On 22/11/2023 at 15:40, johny said: yes think thats the only way to calculate it. Otherwise brim tank and it will expel excess coolant on heating to draw air back in when cooling and the cold level is then what should be maintained? Filling close to the brim will always lose more coolant than required I have found. The tank needs to be very wide. Glad I found the cylinder type. Cheers, Iain. Link to comment Share on other sites More sharing options...
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