NigelH Posted August 27, 2019 Report Share Posted August 27, 2019 Hi All, Took the motor for a stretch in the sun yesterday. Filled the rad with water (extended neck type rad) to 1/2" below the cap. Drove for 10 mins and stopped for petrol, to find a mass of water dumped under the car. Let it cool and checked the level and it had dropped about 1".. drove to Curborough and parked on tarmac..not a drop lost.. Drove the car home a couple of hours later..let it cool and checked the level..no loss from the last check.. Any ideas on the issue? Did I overfill? It was running a bit hotter than normal, about a needle thickness.. Quote Link to post Share on other sites
RogerH Posted August 27, 2019 Report Share Posted August 27, 2019 Hi Nogel, you over filled it. Instead 1/2" below the top try 1/2" above the bottom of the neck. Roger Quote Link to post Share on other sites
NigelH Posted August 27, 2019 Author Report Share Posted August 27, 2019 Thx Roger.. The water is normally at that level..I topped up as it was a scorching day..my bad.. Quote Link to post Share on other sites
monty Posted August 27, 2019 Report Share Posted August 27, 2019 As Roger said filled too much & expansion lost some water. Done it myself! Quote Link to post Share on other sites
NigelH Posted August 29, 2019 Author Report Share Posted August 29, 2019 Guys, please humour me.. So the water level is now 1/2" off the base , but, if I then consider that level across to the thermostat, then there is no/little water at the stat itself, (the cap is level with the top of the stat housing.) So how does that work then? Please be polite and use small words.. Quote Link to post Share on other sites
RogerH Posted August 29, 2019 Report Share Posted August 29, 2019 Hi Nigel, yes - I often wonder that myself. The water will expand - as you have noticed. Also the pump will push the water round. It does work - honest. You can raise the rad a little but be careful of the bonnet touching. Roger Quote Link to post Share on other sites
Mick Forey Posted August 29, 2019 Report Share Posted August 29, 2019 I fitted a water expansion bottle from a TR6 to my TR3. Works a treat. The bottle is hidden. I topped the water up to the filler cap and half way up the bottle. I have not added any all summer, still nearly half way up the bottle. Mick Quote Link to post Share on other sites
Z320 Posted August 29, 2019 Report Share Posted August 29, 2019 (edited) 8 hours ago, NigelH said: Guys, please humour me.. So the water level is now 1/2" off the base , but, if I then consider that level across to the thermostat, then there is no/little water at the stat itself, (the cap is level with the top of the stat housing.) So how does that work then? Please be polite and use small words.. It will work, don't worry about the air and all the stories told about. Do not fill more coolant in the rad as due to the workshop manual and everything will work. If you are ready for "big" words browse the forum. Ciao, Marco Edited August 29, 2019 by Z320 Quote Link to post Share on other sites
ianc Posted August 30, 2019 Report Share Posted August 30, 2019 Why not convert to a sealed system, as used on all modern vehicles? See my article in Section B18 of the Technicalities CD. Such an arrangement ensures that the radiator & thermostat housing are full of coolant at all times. Ian Cornish Quote Link to post Share on other sites
Z320 Posted August 30, 2019 Report Share Posted August 30, 2019 Don't all TRs already have a sealed system? Quote Link to post Share on other sites
Lebro Posted August 30, 2019 Report Share Posted August 30, 2019 Yes & no. It is sealed up to the point that the 4PSI pressure cap opens up, then excess air (or water) is released to the road. Add an expansion bottle as per TR4 etc & the water will fill that instead, but may not find its way back to the rad upon cooling. If the top seal of the pressure cap is 100% though, & the connecting pipe has leak proof ends, then the water will be pulled back into the rad on cooling. That is my current setup, & I can fill my rad right up to the top, & not loose any water. The ultimate system would be to have a pressurised header tank connected to the rad, which has a plain sealed cap on it, the pressure cap now being on the header tank as in modern cars. I know many people have done this. Bob. Quote Link to post Share on other sites
stuart Posted August 30, 2019 Report Share Posted August 30, 2019 22 minutes ago, Lebro said: The ultimate system would be to have a pressurised header tank connected to the rad, which has a plain sealed cap on it, the pressure cap now being on the header tank as in modern cars. I know many people have done this. Bob. As fitted to my 4a. Stuart. Quote Link to post Share on other sites
Z320 Posted August 30, 2019 Report Share Posted August 30, 2019 (edited) 3 hours ago, Lebro said: Yes & no. It is sealed up to the point that the 4PSI pressure cap opens up, then excess air (or water) is released to the road. Add an expansion bottle as per TR4 etc & the water will fill that instead, but may not find its way back to the rad upon cooling. If the top seal of the pressure cap is 100% though, & the connecting pipe has leak proof ends, then the water will be pulled back into the rad on cooling. That is my current setup, & I can fill my rad right up to the top, & not loose any water. The ultimate system would be to have a pressurised header tank connected to the rad, which has a plain sealed cap on it, the pressure cap now being on the header tank as in modern cars. I know many people have done this. Bob. Hi Bob, yeah I know, my TR4A runs with a 13 PSI cap and I realized the bottle always as an "overflow bottle" for the case of emergency and not as an always working "expansion bottle" (return water always with fresh oxygen). As I know the system needs about 1 liter of air to be compressed by the expanding water to limit the pressure. So I fill it up "low" as shown in the TR4A manual and so my bottle is always dry. The air is needed and no problem for the cooling system at all, the water pump is powerful enough to pump a coolant - air - mix. There is no air trapped anywhere when the pump runs and there is no bleeding problem at all, what is a very popular story. Don’t worry about the air. Ciao, Marco my TR only ideling, Thermostat is beginning to open (please never drive mit clear PVC hoses) still engine only ideling , thermostat opened (please never drive with clear PVC hoses) Edited August 30, 2019 by Z320 Quote Link to post Share on other sites
NigelH Posted January 5, 2020 Author Report Share Posted January 5, 2020 Realise this was due to the wrong cap fitted when car was purchased.. Quote Link to post Share on other sites
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