Delberts Wallet Posted March 14, 2002 Share Posted March 14, 2002 I've just noticed that my temp gauge isn't working. So I can tell if its the gauge or the sender what should the resistance be across the sender be with the engine upto temp. Cheers Gareth Who Dares Twins bum.gif bum.gif Edited by - Gareth Harrold on 18 Mar 2002 14:06:59 Link to comment Share on other sites More sharing options...
Foxy Smith Posted March 14, 2002 Share Posted March 14, 2002 Having had similar problems I saved this table and found that it was roughly correct for the sender on my Vx when tested in a cup of water cooling from boiling. In the end it turned out there was nothing wrong with the sender or gauge just a high capacity ally radiator that was'nt allowing the engine to come up to temp, solved prblem with a hardboard radiator blind. Hope this helps. Temp Resistance deg C ohms 45 263 50 224 55 190 60 162 65 137 70 117 75 99 80 84 85 72 90 61 95 52 100 44 105 37 110 32 115 27 120 23 Link to comment Share on other sites More sharing options...
Delberts Wallet Posted March 18, 2002 Author Share Posted March 18, 2002 OK thanks for that. But eeerr where is the sender on a K series? Who Dares Twins bum.gif bum.gif Edited by - Gareth Harrold on 18 Mar 2002 14:06:25 Link to comment Share on other sites More sharing options...
TomGaval Posted March 18, 2002 Share Posted March 18, 2002 The water rail is where mine's located. Link to comment Share on other sites More sharing options...
Bricol Posted March 18, 2002 Share Posted March 18, 2002 Got exactly the same problem on my K-series powered beastie - occasionally works, occasionally doesn't! No idea why it does either. Usually stops reading on long motorway runs but heater still giving heat so engine not cooling excessively. Everytime i try to find cause, it starts working again so I'm non the wiser! Bri Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted March 18, 2002 Share Posted March 18, 2002 Gareth. You can test the gauge by earthing out the feed. Take the female spade connector off the sender unit (on water rail) and use a piece of wire with a male spade terminal attached to it (or a bared section of the wire stuffed into that loom connector)to earth it to the body/neg on batt. Easiest to get someone else to ground it as you watch gauge with the ignition on. If all's well with the gauge it'll flash round clockwise to the upper limit in about 3 nanno seconds!!!Replace sender. No movement suggests gauge U/S. Link to comment Share on other sites More sharing options...
Delberts Wallet Posted March 19, 2002 Author Share Posted March 19, 2002 Thanks Chris. I'll give it ago sometime tomorrow. Cheers Gareth Who Dares Twins bum.gif bum.gif Link to comment Share on other sites More sharing options...
Delberts Wallet Posted March 19, 2002 Author Share Posted March 19, 2002 Thanks all. Tried out Chris' suggestion and it turned out to be the sender. A quick trip to Caterham Midlands for a new one and now as good as new. Gareth Who Dares Twins bum.gif bum.gif Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted March 19, 2002 Share Posted March 19, 2002 I'm glad it was the cheaper of the two options!!! Link to comment Share on other sites More sharing options...
gin-fizz-whizz Posted April 18, 2021 Share Posted April 18, 2021 Stopped for petrol this afternoon and on restarting the engine, the gauge hardly moved. Stayed that way (with just a small movement up to about 40C) for the 5 mile drive home. Gauge seems to work due to this minor movement and also is illuminated when the side-lights are on.Car is a 2001 1.6K Series Supersport EU3. Tried the test mentioned above: "You can test the gauge by earthing out the feed. Take the female spade connector off the sender unit (on water rail) and use a piece of wire with a male spade terminal attached to it (or a bared section of the wire stuffed into that loom connector)to earth it to the body/neg on batt. Easiest to get someone else to ground it as you watch gauge with the ignition on. If all's well with the gauge it'll flash round clockwise to the upper limit in about 3 nanno seconds!!!Replace sender. No movement suggests gauge U/S."Assuming I've done it correctly by running a wire from the disconnected female terminal taken from the single point (on the right in photo) to the battery earth. Did not touch the plug on the left other than to check it's secure.Gauge seems okay as needle moved all the way round almost immediately.Any other tests I can do to eliminate loose connections and/or bad earths?Sorry, for the numpty questions - if the sensor is faulty (as seems to be the case) then which of these items is it? Cannot see any parts on Caterham website for K-series water temp sensors other than this https://caterhamparts.co.uk/senders/17-temperature-sender-water-all-variants-96.html?search_query=temperature+sensor&results=59. Also, how do you change it and does the system need to be re-bled afterwards? Link to comment Share on other sites More sharing options...
SM25T Posted April 18, 2021 Share Posted April 18, 2021 Redline will stock it. Temperature sender Rover. With engine cold and pressure released at expansion cap, refit cap then replace sender. You won't lose much coolant at all Link to comment Share on other sites More sharing options...
Roadsport06 Posted April 18, 2021 Share Posted April 18, 2021 Sensor is the smaller of the two on the rail. You can un screw and put it into boiling water to check in case there is an issue with your cooling system. New one just screws in. Minimal coolant will seep out the water rail, thumb over it. I just top up from a bleed tee in the top hose of the heater Link to comment Share on other sites More sharing options...
gin-fizz-whizz Posted April 18, 2021 Share Posted April 18, 2021 Thanks but think I don't have a bleed tee as standard.Am I correct in thinking that this smaller sensor is just for the gauge? The larger sensor in front of it on the water rail is for the ECU and more important functions and that the fan either uses this or has it's own sensor near the radiator. Put another way, is the car probably ok to use? Link to comment Share on other sites More sharing options...
Roadsport06 Posted April 18, 2021 Share Posted April 18, 2021 The smaller one is for the gauge. Your fan switch is in the rad. No need for a bleed tee but it makes that the highest point if you need to top up To help ensure there are no air locks. https://www.ebay.co.uk/itm/Caterham-Westfield-kit-car-Land-rover-Bleed-Tee-Coolant-valve-/292744817013?_trksid=p2349624.m46890.l49286 Link to comment Share on other sites More sharing options...
SM25T Posted April 19, 2021 Share Posted April 19, 2021 The temperature gauge sensor can be notoriously short lived and prone to heart stopping moments when you glance at the gauge. I have taken to covering the top with araldite when I fit a new one, leaving the connector lug clear, as the connector part can rotate. Link to comment Share on other sites More sharing options...
Wrightpayne Posted April 19, 2021 Share Posted April 19, 2021 This is the common one used...https://caterhamparts.co.uk/senders/17-temperature-sender-water-all-variants-96.html?search_query=Sender&results=67 Link to comment Share on other sites More sharing options...
gin-fizz-whizz Posted April 24, 2021 Share Posted April 24, 2021 Oh this is frustrating. From notes above . . . . . 1/ Tested gauge by earthing to battery negative terminal. Needle spins round to maximum so not a gauge problem. Just for good measure, removed it from dash, checked the connectors and put it back. Tested by earthing again to make sure and still ok.2/ Before fitting new sensor (part above), I removed the female spade connector again from the current sensor and connected it to the new one. Immersed to c. 1cm in both warm and hot water (between 40 and 90C). Ignition on and gauge doesn't register anything.So what else can it be? It's such a simple little circuit so all I'm thinking is a) does the new sensor need to be in-situ?b) have a got a dud new sensor? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 24, 2021 Member Share Posted April 24, 2021 Private Message sent. Link to comment Share on other sites More sharing options...
SM25T Posted April 24, 2021 Share Posted April 24, 2021 If you just dunked it in hot water, you are not completing the electrical connection ... body needs grounding to earth. Link to comment Share on other sites More sharing options...
gin-fizz-whizz Posted April 26, 2021 Share Posted April 26, 2021 I see. Have just redone the test correctly on the the new sensor. Hot water about 70C gives a resistance on my 20kohm meter of 1.04 then as it cools to ambient temperature I watched the resistance steadily rise to 1.81. This suggests the new sensor is okay.I then removed the old sensor and same test showed same 'OL' (open circuit) resistance readings regardless of temperature. Looks like the old sensor is the issue. Fitted the new sensor in and connected morning with negligible loss of coolant in the process. Run engine up to temperature, gauge moved smoothly round from 40 to low 90s, then thermostat opened on cue, fan started and ran for about 2 mins to take it back down to high 80s. Heater working too.Decent run out later on in the afternoon and perfect. Thank you everyone for input. Link to comment Share on other sites More sharing options...
wardybits Posted August 9, 2022 Share Posted August 9, 2022 This is a useful thread :) My K-series temp gauge has become increasingly erratic over the last month, it doesn't go over 80 but does like to dance about below that. I'll run through the tips and tricks above and see where I get, here's hoping it something simple like the sensor! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 9, 2022 Member Share Posted August 9, 2022 I'd certainly do a quick test: ignition ON, detach the lead to the sensor and look at the gauge, then short the lead to earth and look at the gauge.Please let me know if you'd like a wiring diagram.Jonathan Link to comment Share on other sites More sharing options...
wardybits Posted August 9, 2022 Share Posted August 9, 2022 Thanks Jonathan I think I have all I need for now but I'll certainly be back if I hit a hitch. Link to comment Share on other sites More sharing options...
wardybits Posted August 13, 2022 Share Posted August 13, 2022 Gauge tested and working, new sensor fitted from Redline, that seems to have sorted things! It's running steady at 85/90 is that normal for a1.8 K-series? Link to comment Share on other sites More sharing options...
SM25T Posted August 13, 2022 Share Posted August 13, 2022 Yes ... if you have an 88C thermostat ? I changed mine to an 82C stat Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now