m1chaelw Posted November 9, 2017 Share Posted November 9, 2017 I'm wondering if anyone has any up to date information on how to go about this . All the threads I've read have been a good few years old. Is it still the case of a Range Rover expansion cap with a custom circuit ? If so now that these circuits have been out there a while , which has worked best . If someone could point me in the right direction as im not too experienced in electronics Thanks in advance Mike Quote Link to comment Share on other sites More sharing options...
SPendrey Posted November 9, 2017 Share Posted November 9, 2017 I used one of these kits, although I'm sure it was half that price a few years back?! http://www.ebay.co.uk/itm/Low-Coolant-Level-Alarm-12V-60mm-Screw/172766919492?epid=1488315648&hash=item2839b5fb44:g:89IAAOxyGxxSLdwA Simple to install, but does require holes in the expansion tank. Quote Link to comment Share on other sites More sharing options...
m1chaelw Posted November 9, 2017 Author Share Posted November 9, 2017 (edited) I had a look in to these , the drilling the expansion tank put me off a little . I wonder if it would work along side the PRC7925 coolant cap ? Anyone tried one of these: http://www.cartekmotorsport.com/CARTEK COOLANT LEVEL SENSOR Instructions.pdf Edited November 9, 2017 by m1chaelw Quote Link to comment Share on other sites More sharing options...
AMB Posted November 9, 2017 Share Posted November 9, 2017 I used the Range Rover cap with one of the many published custom designs. Just modified the design so that it didn't alarm on bumps. Didn't fancy drilling into the expansion tank to insert the screws. Quote Link to comment Share on other sites More sharing options...
mmgemini Posted November 9, 2017 Share Posted November 9, 2017 Nothing has changed since the original one was made. You may either use the Range Rocer cap or you can buy a Discovery one that fits straight into the plastic header tank Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted November 9, 2017 Share Posted November 9, 2017 The Bearmach cap and float switch that I bought contained nothing more complex than a magnet and reed switch, one relay and buzzer later and it was all done. I've never seen the original RRC 'switch' dissected and cant see any reason why the original switch would be more complex. Quote Link to comment Share on other sites More sharing options...
m1chaelw Posted November 9, 2017 Author Share Posted November 9, 2017 (edited) Thanks for the replys guys , appreciate it has anyone got the original wiring diagram ? All the images have gone on the threads ive found . Closest one I've found is : https://www.landroverexpedition.com/technical/300tdi-low-coolant-alarm/ Edited November 9, 2017 by m1chaelw Quote Link to comment Share on other sites More sharing options...
Les Brock Posted November 9, 2017 Share Posted November 9, 2017 There might be some in my build thread linky below.... Quote Link to comment Share on other sites More sharing options...
dailysleaze Posted November 9, 2017 Share Posted November 9, 2017 3 hours ago, m1chaelw said: Thanks for the replys guys , appreciate it has anyone got the original wiring diagram ? All the images have gone on the threads ive found . Closest one I've found is : https://www.landroverexpedition.com/technical/300tdi-low-coolant-alarm/ This has worked well for me in the last 5 years. It comes on when I brake hard so I know it's still working Quote Link to comment Share on other sites More sharing options...
TSD Posted November 9, 2017 Share Posted November 9, 2017 (edited) The G5V relays in the landroverexpedition link have a very low current coil, it might very well work fine run direct from the sensor without the transistor. If I remember rightly, the LR cap has a resistor in series with the reed relay in the cap. I can't remember the resistance though - will have to dig back in my notes. EDIT : Dug through the debris of my old website, the LR sensor cap PRC7925 has a resistor of about 680 ohms in series with the reed switch, so even the little G5V relay will probably not operate reliably without the buffer transistor. I've made a few solid state (ie no relay) ones for people over the years. The first one is more than 10 years old, and was working perfectly this morning when my radiator sprang a leak My expansion tank is mounted sideways, so it doesn't flicker on braking, but it does on enthusiastic cornering! I'll have to make another at some point for the new Ibex build, I think this time it needs a small time delay to stop the flicker, and a flasher for the warning light. Edited November 9, 2017 by TSD Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted November 10, 2017 Share Posted November 10, 2017 There is no such series resistor in the Bearmach cap that I purchased a couple of years ago and it switches a relay with no problem. It is of course N/C when the coolant is present and as such it requires the condition inverting to sound an alarm. Where is the 680R resistor in the original cap (if it exists) ? Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted November 10, 2017 Share Posted November 10, 2017 I just used the cap and relay, no fancy circuit. just make sure you get a relay with an 87a contact which is normally closed with no power to it such as this one. http://uk.rs-online.com/web/p/products/7826950/?grossPrice=Y&cm_mmc=UK-PLA-DS3A-_-google-_-PLA_UK_EN_Relays-_-General_Purpose_Relays-_-PRODUCT+GROUP&matchtype=&gclid=EAIaIQobChMI6NKQ_byz1wIVjpztCh1DzwBWEAQYASABEgKwbPD_BwE&gclsrc=aw.ds Quote Link to comment Share on other sites More sharing options...
mmgemini Posted November 10, 2017 Share Posted November 10, 2017 15 hours ago, m1chaelw said: Thanks for the replys guys , appreciate it has anyone got the original wiring diagram ? All the images have gone on the threads ive found . Closest one I've found is : https://www.landroverexpedition.com/technical/300tdi-low-coolant-alarm/ Yes I have a copy of the one made for Difflock Quote Link to comment Share on other sites More sharing options...
TSD Posted November 10, 2017 Share Posted November 10, 2017 3 hours ago, GW8IZR said: Where is the 680R resistor in the original cap (if it exists) ? It doesn't take much to imagine where it could be (and only a little more to think why it might be there) Gen parts VDO cap measured this morning. You can make out the LR oval embossed on the top. Sorry for the bad photography, but that says 0.682 kOhms Brand new bearmach copy. Approx 4.6 Ohms. You'll have to excuse the chinese test leads Paul, but they only added about 0.35 Ohms error. So perhaps one of those rare cases of pattern parts not made to drawing? Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted November 10, 2017 Share Posted November 10, 2017 For sure, I'm asking where it is located to determine whether it could be bi-passed, none of the after market designs appear to use the eol detection or current limiting properties of that resistor.. its just an inconvenience to anyone doing a simple alert. Quote Link to comment Share on other sites More sharing options...
TSD Posted November 10, 2017 Share Posted November 10, 2017 If anyone wants to swap their new gen parts sensor for my bearmach one, I'm game... Quote Link to comment Share on other sites More sharing options...
m1chaelw Posted November 10, 2017 Author Share Posted November 10, 2017 2 hours ago, mmgemini said: Yes I have a copy of the one made for Difflock Brilliant , will be interested to take a peak at this if you could post it up Interesting to read about the copied caps showing different resistance , need to check which one I've ordered Quote Link to comment Share on other sites More sharing options...
m1chaelw Posted November 11, 2017 Author Share Posted November 11, 2017 Sorry to sound like a muppet here , first time I've done anything like this . https://www.landroverexpedition.com/technical/300tdi-low-coolant-alarm/ I see on the shopping list on this link an in line fuse holder . Is this so you can tap in to the 12v ignition circuit without using an already fused point if that makes sense ? Quote Link to comment Share on other sites More sharing options...
mmgemini Posted November 12, 2017 Share Posted November 12, 2017 m1chaelw Send me youe mobile number by PM and I'll send it t you http://forum.difflock.com/viewtopic.php?t=10972&highlite=300tdi+coolant=level+switch read that and the links Quote Link to comment Share on other sites More sharing options...
western Posted November 12, 2017 Share Posted November 12, 2017 I have the same module as mmgemini, it works very well, I have the modules green led for all correct & on my td5 warning light panel used the 'fuel in water' led for a low coolant level, so its fail safe. IIRC my wiring diagram is near the end of the difflock thread & its on this forum too. Quote Link to comment Share on other sites More sharing options...
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