green george Posted August 31, 2016 Share Posted August 31, 2016 My car is a EU2 1.6 K series SuperSport. I have noticed that in stop start traffic the water temperature is registering 100 degrees which I don't recall it doing before. The fan cuts in as normal but the temperature stays at 100 degrees until I move off and have airflow through the radiator again. I have noticed this twice lately on hot days. I initially put this down to the high ambient temperatures but just wanted to see what your thoughts are.The car was serviced recently, but the cooling system was not worked on to my knowledge. There are no obvious leaks with the coolant level as expected. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 31, 2016 Member Share Posted August 31, 2016 Is the fan pushing air the right way?Jonathan Link to comment Share on other sites More sharing options...
SM25T Posted August 31, 2016 Share Posted August 31, 2016 Second that suggestion. Also it may be the temperature sender failing ... they are notoriously crap ..... or the expansion bottle cap failing. Link to comment Share on other sites More sharing options...
Bio Posted August 31, 2016 Share Posted August 31, 2016 Does the fan cut in and then out? The fan is controlled separately from the temperature gauge. If this is working properly then the problem could be the gauge sender. Link to comment Share on other sites More sharing options...
SM25T Posted August 31, 2016 Share Posted August 31, 2016 See if all hoses are equally hot once the engine warms up. If you have a heater .... check inlet and outlet hoses to it. Very common place for an airlock. Might have had one there for a while .... released into the system once you open the heater valve. A cold hose tells you there is an airlock preventing water circulation. Link to comment Share on other sites More sharing options...
green george Posted August 31, 2016 Author Share Posted August 31, 2016 Jonathan - Is the fan pushing the right way? I will check. Is the electrical connection two way; so it could be connected incorrectly reversing the motor? Will have a look tomorrow as I am currently nights.SM25T & Bio - The fan cycles apparently normally and comes on when the water temperature reads just over 80 degrees (presumably a 82 degree thermostat). I have ordered a new expansion bottle cap and will order a new water temperature sender although I need to speak to Caterham parts as the new sender unit uses a cylindrical connector as opposed to the usual blade one; and I am not sure what connector it now takes.I will check the hoses tomorrow, paying attention to the heater hoses.Thanks Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 31, 2016 Member Share Posted August 31, 2016 Is the fan pushing the right way? I will check. Is the electrical connection two way; so it could be connected incorrectly reversing the motor? It certainly can happen, but I don't know if it's always because of reversed wiring (usually at the motor) or if the connector can be connected the wrong way. You can short the wire at the sensor to test the fan motor without needing to get the coolant hot.Jonathan Link to comment Share on other sites More sharing options...
DJ. Posted August 31, 2016 Share Posted August 31, 2016 If the temperature stays at the normal 80 on a hot day while driving, it sounds like the cooling system is working well. Also if the fan cuts in at the usual indicated temperature, it sounds like the temperature sensor and fan switch are Ok. If you haven't lost any water, it seems to me that the only element of the system that isn't functioning correctly is the fan. And as you can hear it running, it does sound like it is going the wrong way. I hope it is, because it's a cheap fix Link to comment Share on other sites More sharing options...
green george Posted August 31, 2016 Author Share Posted August 31, 2016 Right! WIll check the fan tomorrow! Have ordered a new cap and sender unit; I found a post by SM25T indicating that the cylindrical sender connector uses the same connector but mounted at 90 degrees.DJ. - When moving the temperature sits at 80 degrees as normal. The front end was recently stripped down to have the suspension powder coated so will check the connection tomorrow. Jonathan - excuse my ignorance but where is the fan sender and how do I short it?Testing the fan: Presumably this is as simple as the fan should be blowing air from the rad into the engine bay and NOT back through the radiator? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 31, 2016 Member Share Posted August 31, 2016 ... where is the fan sender and how do I short it?The widget in the radiator with a wire connected to it. Have a look and tell us what colour wires you find. (But you're going to mimic the sender closing the circuit as it gets hot.)Testing the fan: Presumably this is as simple as the fan should be blowing air from the rad into the engine bay and NOT back through the radiator?Yes. Jonathan Link to comment Share on other sites More sharing options...
SM25T Posted August 31, 2016 Share Posted August 31, 2016 The fan switch in the top of the rad has two pins that the connector pushes on to. Unplug the connector and connect the two connectors together .... paper Clip or pair of pliers. Ignition must be on. Expect a spark ! Link to comment Share on other sites More sharing options...
SM25T Posted August 31, 2016 Share Posted August 31, 2016 A year ago at the Swiss international meeting .... a brand new car arrived .... It was blowing hot air forwards out of the nose cone ..... almost certainly a case of the fan wires connected the wrong way round !! Link to comment Share on other sites More sharing options...
Dixa1225 Posted August 31, 2016 Share Posted August 31, 2016 Can the wires on the fan switch causes the motor to blow the wrong way ? Surely the wiring to the motor being wired incorrectly would cause this ? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 31, 2016 Member Share Posted August 31, 2016 Can the wires on the fan switch causes the motor to blow the wrong way ? Surely the wiring to the motor being wired incorrectly would cause this ? "No" and "Agreed". If that's a response to #7 I couldn't remember how it's connected, but both options were about the feed to the fan motor.Jonathan Link to comment Share on other sites More sharing options...
green george Posted September 1, 2016 Author Share Posted September 1, 2016 Thank you for all your advice.This morning I carefully checked everything and found nothing untoward. So I rang Seven & Classics who suggested I popped in for them to have a look. What an excellent outfit they are. Brian Attwood examined the cooling system with the engine running and using an infra red thermometer confirmed that everything was working correctly including the fan switch. The conclusion was that the higher than normal reading was most likely due to the high ambient temperatures aggravated by being held stationary in traffic for a prolonged periods so that heat sink from exhaust primary(s) directly below the water temperature sender caused the under bonnet temperature to rise significantly. Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted September 1, 2016 Area Representative Share Posted September 1, 2016 In my old Super Sprint, it used to have overheating problems in traffic. I fitted an override switch onto the fan sensor that permanently switched the fan on. So when approaching stationary traffic, I would switch the fan on and this kept the temperature under control and it did not overheat so easily.However, I have not had to do it yet to my K series 7. Piers Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 1, 2016 Member Share Posted September 1, 2016 My 1800 K behaved the same way... until it was rebuilt. The only difference on paper is a lower temperature thermostat.Jonathan Link to comment Share on other sites More sharing options...
Bio Posted September 1, 2016 Share Posted September 1, 2016 If the fan cycles normally then I suspect a faulty temperature sensor thus an incorrect temp gauge reading.Does the car actually run hot? Link to comment Share on other sites More sharing options...
green george Posted September 1, 2016 Author Share Posted September 1, 2016 Hi Bio, the engine is fine in normal driving but when stationary the gauge shows 100 degrees which is unusual for my car. Seven & Classics went over the engine today and gave it a clean bill of health. Link to comment Share on other sites More sharing options...
Bio Posted September 1, 2016 Share Posted September 1, 2016 Does the temperature creep up to 100 degrees from normal when stationary....what happens when stationary does the fan run to bring the temperature down? Link to comment Share on other sites More sharing options...
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