TopQ1967 Posted May 5, 2006 Share Posted May 5, 2006 Hi, My water temperature is running to hot (hitting 120 deg. C). I have no thermostat fitted so that can’t be the problem. I have a temp sensor fitted in my 3- core radiator. The (standard) fan didn’t go on, so I made a bypass on the road this afternoon to control the temp. It is still hitting 120 deg. C. All hoses are getting hot, so I presume this is o.k. Question: Help, what could this be? I fitted one wire for the thermostat out of my R400 loom (probably for a Stack sensor) on a sensor that is fitted to the water rail on the left hand side of my engine. Is the water temp also used by the standard MBE R400 ECU? If not I can remove this wire. I have the original fan that was mounted at the front also. How is it fitted? (I have no space). Pictures please? Cheers, TopQ1967 Edited by - TopQ1967 on 5 May 2006 14:21:58 Link to comment Share on other sites More sharing options...
mav Posted May 5, 2006 Share Posted May 5, 2006 Have you checked for airlocks? Are you using matched guage and sender? Link to comment Share on other sites More sharing options...
TopQ1967 Posted May 5, 2006 Author Share Posted May 5, 2006 Mav, The guage and sender are the same as used in my VVC. With the VVC engine it worked fine. If I have airlocks, I think not all hoses would be warm and I see not why the watertemp in my radiator would rase then. At what temp is the fan normally started? Is it controled by the ECU? Cheers, Q. Edited by - TopQ1967 on 5 May 2006 14:34:44 Link to comment Share on other sites More sharing options...
Adrian M Posted May 5, 2006 Share Posted May 5, 2006 TopQ1967 it sounds as if you’ve got an ex race R400 like me. If you’re using your old standard gauges you will need to swap the Stack water and oil temp senders to the standard Rover ones. Stack senders have 2 pins where as the Rover ones have 1. Hooking Caterham gauges up to stack senders will make the over read, have you checked the water rail temp? Ade Link to comment Share on other sites More sharing options...
TopQ1967 Posted May 5, 2006 Author Share Posted May 5, 2006 Dear Adrian, I have a one- pin sensor in my waterrail. I will check what the part no stamped in is saying. Out of the R400 loom there are two wires for the sensor one was fitted to the sensor (eart leving open). If I disconnect the wire, the reding on the gauge is still there I have a two- pin sensor (or is this a swich?) on my radiator. This was original also on the radiator that was used when the VVC sat in. Cheers, Q. Link to comment Share on other sites More sharing options...
TopQ1967 Posted May 5, 2006 Author Share Posted May 5, 2006 Dear Adrian, You ware right concirning the sensor. The oil sensor fitted in the dry- sump belhousing is still of Stack origin. I presumed on my one - by switch - operated temp gauge, that the highest temp was the water temp. This seems now to be the stack sensor (oil). Thank you and have a nice weekend, Quirin Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted May 5, 2006 Support Team Share Posted May 5, 2006 The thing in the radiator is a fan switch. It should switch the fan on at about 98 degrees and off again at about 92. The water cannot really be running at 120 degrees - the pressure would have blown the seal on the expansion tank if nothing else. It is most likely that the sensor or the wiring is faulty. There are two sensors - one for the ECU and one for the temperature gauge. I can't remember which is which but one is in the water rail and one is in a hose at the back of the engine (not far from the water rail). I assume that 120 degrees on the dial is full deflection - this would suggest that the connection is short circuited. I can't help much more than that but it might give you some pointers. Yellow SL #32 Link to comment Share on other sites More sharing options...
TopQ1967 Posted May 5, 2006 Author Share Posted May 5, 2006 Shaune, It was not at full deflection, you are otherwise right, see my previous mail. Thank you, Quirin Link to comment Share on other sites More sharing options...
Adrian M Posted May 5, 2006 Share Posted May 5, 2006 TopQ1967 my R400 loom didn’t have the stack sensor wires in. When I fitted the engine there was no water temp wire, I opened up the loom where it runs across the front of the scuttle and found the wire there (from memory I think its green). You will be able to replace the oil temp sensor in the bellhousing with a Rover one as they’re the same thread. As Shaun says the sensor in the radiator is more than likely the original rad fan switch. The R400 race engines had an additional relay modification (available from CC) that uses the ECU to trip the rad fan. Ade Link to comment Share on other sites More sharing options...
TopQ1967 Posted May 6, 2006 Author Share Posted May 6, 2006 Adrian, I have the CC relais as well. This is currently not fitted. The relais was used for the heavyer front mounted fan. I don't have space to fit it (the fan that is). Do you know how they fit it on a R400 race Caterham? I have now rubbers between my radiator and chassis (as original). Parhaps if I remove these it will fit, but I think it is wiser to leave them in place. Cheers, Quirin Link to comment Share on other sites More sharing options...
Number31 Posted May 6, 2006 Share Posted May 6, 2006 Try this R400 Engine Gallery There isn't a front on shot but you should be able to figure out how the big fan is installed. Cheers. Number31. Link to comment Share on other sites More sharing options...
davef Posted May 6, 2006 Share Posted May 6, 2006 N31 - interesting set of pictures. I'm fitting a R400 at the moment - a couple of questions: - the orange wire from the ECU plug - where have you wired this through to?? - brown /white wire from the loom - I'm assuming this is the switched power for the fuel pump?? Cheers, Dave Link to comment Share on other sites More sharing options...
TopQ1967 Posted May 6, 2006 Author Share Posted May 6, 2006 Hi No.31, Is this your car? On pic. 7 I see an orange wire coming out of the ECU. I beleive this is for the fan relais controll. I tought it had a strange connection (pin, not fitting to the female connection on the relais). But on this picture it is completely the same! I see no rubbers between rad and chassis as well. Is this allright for road use (not as flat as race track)? Cheers, Q. Link to comment Share on other sites More sharing options...
Number31 Posted May 6, 2006 Share Posted May 6, 2006 Yes its my car, though the pictures were taken before it had a make over this winter! See Here and Here The orange wire is the fan relay control but comes with the fan control kit and is inserted into the MBE plug to finish it off, both my car and the spare fitting kit we have were both exactly the same. I would guess that if the solid mount rad works on the track you should be OK on the road? Number31. Link to comment Share on other sites More sharing options...
TopQ1967 Posted May 6, 2006 Author Share Posted May 6, 2006 Thank you for the pic's. I have the same fan control, and ECU orange wire connection. I will try connecting the rad without the rubber maunting points. < off topic> I see you swapt to Duratec as well. My engine came from Parker Racing they ware swapping to duratec's also. Is it better than the R400? in what way? Cheers, Quirin Link to comment Share on other sites More sharing options...
Myles Posted May 6, 2006 Share Posted May 6, 2006 I would guess that if the solid mount rad works on the track you should be OK on the road? Sounds like a recipe for a leaking rad over time. Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
davef Posted May 6, 2006 Share Posted May 6, 2006 In answer to my own question, the brown / white lead is the supply for both the fuel pump and the starter solenoid (which in my seven connected to a purple wire from the fuse box) Dave Link to comment Share on other sites More sharing options...
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