perrett Posted November 25, 2020 Share Posted November 25, 2020 Hi allCold bottom hose. Thermostat works ok in a pot of boiling water. Not really sure where to look next. Can a thermostat have an intermittent operation.cheer Link to comment Share on other sites More sharing options...
SM25T Posted November 25, 2020 Share Posted November 25, 2020 Airlock in top of radiator or heater. Have you got a bleed tee in the highest heater hose. Link to comment Share on other sites More sharing options...
perrett Posted November 25, 2020 Author Share Posted November 25, 2020 There's a plug/bolt in the top of the radiator, which I've used to release air. Link to comment Share on other sites More sharing options...
SM25T Posted November 25, 2020 Share Posted November 25, 2020 Have you got a heater ? Valve should be open. Inlet and outlet hoses should get equally warm. If the outlet stays cold, there is air in heater. A bleed tee in the middle of the highest heater hose which you can also raise to be higher than everything, will help you fill the heater and displace air. Link to comment Share on other sites More sharing options...
SM25T Posted November 25, 2020 Share Posted November 25, 2020 While the thermostat is out, drill a 3mm hole in the metal back plate .. must be at the top when the thermostat is fitted Link to comment Share on other sites More sharing options...
SM25T Posted November 25, 2020 Share Posted November 25, 2020 Link to comment Share on other sites More sharing options...
garybee Posted November 25, 2020 Share Posted November 25, 2020 Bit more information would be handy. Have you done anything to the car recently or has this occurred after the car was working fine/cooling ok with no other actions? Link to comment Share on other sites More sharing options...
Wrightpayne Posted November 25, 2020 Share Posted November 25, 2020 K series cooling systems in a seven are notoriously difficult to refill. If its been drained and refilled my money is on an air lock. There will be posts in the archive detailing best practice. Best way to find is to search using google.Ian Link to comment Share on other sites More sharing options...
perrett Posted November 25, 2020 Author Share Posted November 25, 2020 Yes I do have a heater. I will check the hose temperatures as you've explained. Thanks Link to comment Share on other sites More sharing options...
perrett Posted November 25, 2020 Author Share Posted November 25, 2020 I will do that. That's a good idea. Makes lots of sense, the more I think about it. Cheers Link to comment Share on other sites More sharing options...
perrett Posted November 25, 2020 Author Share Posted November 25, 2020 I ran the engine for about 40 minutes, after not being started for about 6 weeks. All was ok. Electric fan in and out as expected. Heater valves open and working ok. Took the car out on Saturday for a spin. Temperature gauge passed half way, after 15 minutes. Got it back home, with the gauge reading high, but not in the red! That's when I found the bottom hose cold. Link to comment Share on other sites More sharing options...
perrett Posted November 25, 2020 Author Share Posted November 25, 2020 Thanks all. Plenty of things for me to try. I'll be on it Saturday. I'll keep you posted. Link to comment Share on other sites More sharing options...
SM25T Posted November 25, 2020 Share Posted November 25, 2020 The sender for the gauge is notoriously poor quality. But if the bottom hose remains cold after 40 minutes, there is definitely an airlock Link to comment Share on other sites More sharing options...
K7 VCT Posted November 25, 2020 Share Posted November 25, 2020 My old 1.4k suffered, I found the cure to be jacking up the front of the car as high as possible to get the radiator above the heater, ran car for 10 mins bleeding from top air bleed in rad, all good from then on. Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted November 25, 2020 Area Representative Share Posted November 25, 2020 There is a useful article on the K Series cooling system in the archive:- Modifying the K Series coolant circuit by Ian Blakeman in the September 2012 edition Link to comment Share on other sites More sharing options...
SM25T Posted November 25, 2020 Share Posted November 25, 2020 Certainly worked for me. Rock steady temperatures. Link to comment Share on other sites More sharing options...
Wrightpayne Posted November 26, 2020 Share Posted November 26, 2020 Its still not clear whether anything was done to the car prior to the cold hose occurrence?Stat has been tested but was this before / after cold hose? If after, has the system been tested again? Link to comment Share on other sites More sharing options...
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