CharlesElliott Posted October 12, 2003 Share Posted October 12, 2003 Hi all, Well, it started! Apart from leaving the solenoid lead off by mistake there were no real problems. However, I haven't yet managed to get the radiator fan to come on and may need to bleed some more air from the system. However, the radiator itself doesn't get hot except for the top 'plain' section which the temp switch goes into. Similarly, the lower hose back to the engine remains cool. This doesn't seem right to me - any suggestions? Oh, and the Apollo drain plug leaks but hopefully a bit of a tighten will sort that out. Charles --- My Caterham Academy 2004 Diary Link to comment Share on other sites More sharing options...
Grubbster Posted October 12, 2003 Share Posted October 12, 2003 Hi Charles, Just back from a quick coastal blat! I had a problem getting my fan to run as well, the engine temp got near the red but the bottom of the rad was still cold. It is caused by an airlock, what I did was to get the front of the car as high as possible to make the radiator the highest point, then ran the engine with the top bolt off the radiator, then when the thermostat opened the air 'burped' out! See some photo's of the build here Link to comment Share on other sites More sharing options...
CharlesElliott Posted October 12, 2003 Author Share Posted October 12, 2003 Thanks Steve - I didn't expect an airlock to stop water flowing through the rad properly. I'll give it a go. Charles --- My Caterham Academy 2004 Diary Link to comment Share on other sites More sharing options...
CharlesElliott Posted October 12, 2003 Author Share Posted October 12, 2003 Ran the car with the front up in the air and the bleed screw undone. I did manage to get coolant all over the floor and the raidator did get warm this time, but the temp gauge didn't move above 80 and I got worried so switched it off. Charles --- My Caterham Academy 2004 Diary Link to comment Share on other sites More sharing options...
Tricky Posted October 12, 2003 Share Posted October 12, 2003 80 sounds about right Charles. Its when the gauge is heading 85+ that you should be concerned. Now you've bleed the system run it until the rad fan has been on three times make sure there are no air locks. Mine sits at 80 all day unless on track. Did you fit t he Changeover switch to read oil temp as well? Tricky Academy 2003 Group 1 Number 5 Link to comment Share on other sites More sharing options...
Grubbster Posted October 12, 2003 Share Posted October 12, 2003 That's right - when everything is OK it seldom goes past 80, plus when idling it will take quite a while for the fan to cut in - but it will in the end. Now the coolant is circulating it takes a lot longer to get hot. Sounds like yours is OK now See some photo's of the build here Link to comment Share on other sites More sharing options...
CharlesElliott Posted October 13, 2003 Author Share Posted October 13, 2003 Tricky, Steve, It sounds like I didn't run it for long enough. When the temp gauge stuck at 80 for so long I started wondering whether there was something wrong with the sender..... Still haven't got the fan to come on but it sounds as if it will now with a longer run. Anyway, I now need some more coolant so that delays things for a bit 🙆🏻 Charles --- My Caterham Academy 2004 Diary Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 13, 2003 Share Posted October 13, 2003 Running an engine to hot with no pressure in the system is a STUPID way to bleed anything. Stop now before you make it worse. The system is self-bleeding as long as you get the big airlocks out. Just work methodically. I appreciate you are 90% there now, so it might be fine to just close it up and go with what you've got. [sucking eggs bit] When you are filling from cold, the thermostat is closed. This means that you have two separate circuits to fill: the head circuit and the radiator circuit. The water rail/heater joins the top of these two circuits. If you detach the bypass/heater hose (the long hose that goes down to the thermostat) and fill through this, it will fill the head and vent air back up through the water rail. This will give an almost perfectly bled head and also fill the heater. Remember to have the heater valve open. Do this on the level; raising the front of the car will trap air in the head. You then reattach the hose and open the bleed screw on the radiator. Fill through the expansion tank. This will fill the radiator circuit and the fat pipework leading to the closed side of the thermostat. There will be airlocks. Varying the height of the front of the car will help these airlocks come out but you also need to vigorously flex the lower radiator hose and the J hose. Huge burps of air will come through into the expansion tank. Keep twisting at the submarine pipe to take to flex the hoses and get the submarine pipe horizontal; imagine the air bubble in the hose and guide it to the submarine pipe exit. Keep filling until air comes out of the radiator bleed with the nose of the car in the air; this will ensure that the fill through the radiator has also filled the water rail and the top hose. Last bit is a final vent at the highest point of the system where it gets trapped by the heater. For this you need to have the expansion tank detached from the car so it can be raised so you can see the fluid level is higher than the heater hose - expansion tank cap must be removed. From here, gently ease off the heater/bypass hose; aim to just crack the seal at the top edge of the hose, so you can reattach it quickly. There will be a little rush of air and then a gush of fluid. Reattach. Reattach the expansion tank. Put the lid on and you are ready to run. [/sucking eggs bit] Link to comment Share on other sites More sharing options...
CharlesElliott Posted October 13, 2003 Author Share Posted October 13, 2003 Hi Peter, and thanks for the note. Where exactly is the thermostat? (I don't have a heater BTW). One problem is that being a novice I have to follow the build guide in the event of any prior advice. The build guide says to fill through the expansion tank, run the engine and open the bleed screw which is what I did. On the first run the temperature did rise very quickly, getting to ~100 on the gauge but this now seems to settle around 80 and then rise very slowly. Charles --- My Caterham Academy 2004 Diary Link to comment Share on other sites More sharing options...
BruceW Posted October 13, 2003 Share Posted October 13, 2003 What has always worked for me is slightly different to the above. With the nose up and engine running from cold, loosen the expansion tank screw and remove the bleed screw. You can then carefully top up the system with a little water into the bleed screw hole, this has cleared the airlock each time I've done it. I reckone the final airlock, after all the big ones have gone is usually in the top hose-backfilling seems to clear it. Tighten the expansion tank cap and bleed screw, then run the car and feel that rad get hot all over to confirm. The thermostat is top left of the rad from memory-you should have connected the wires at some point. Bruce Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 13, 2003 Share Posted October 13, 2003 The "themostat" is in the plastic housing on the inlet side of the block where you attach the J hose and the bypass hose. The radiator has a "thermoswitch" in it that is prone to failure. Link to comment Share on other sites More sharing options...
CharlesElliott Posted October 13, 2003 Author Share Posted October 13, 2003 Can anyone do me an idiot's guide of which way the water flows and what happens when the thermostat opens? I don't understand why just the top of the rad is getting hot when presumably the thermostat is closed. Charles --- My Caterham Academy 2004 Diary Link to comment Share on other sites More sharing options...
Grubbster Posted October 13, 2003 Share Posted October 13, 2003 Hi Peter, Thanks for the detailed explanation - I understand exactly what you are saying - the assembly guide explains it in a similar way but I also had problems with airlocks when I filled mine. It certainly makes a difference to squeeze the pipes and 'work' the bubbles through while the engine is running. My cooling system was (in theory) full according to the checks, but obviously there were airlocks and I had the same situation that Charles had. The book says that if this happens to shut down the engine and contact Caterham for advice - so I did - I requested help from the Caterham tech support, but got no reply by a week later so decided to seek out advice from elsewhere. I was advised by a Caterham servicing agent to raise the front of the car (as far as possible) as this was their tried and tested way of solving the problem - I did it and it worked. It sounds like it has cleared Charles problem also (he has no heater so it should be easier). I agree whole-heartedly that if the engine gets hot without the water circulating (i.e. the rad stays cold) this could damage the engine - so in this situation don't persist but shut it down. There is also quite a bit more on this at: http://www.blatchat.com/T.asp?id=36822 it seems to be a common problem! See some photo's of the build here Edited by - Grubbster on 13 Oct 2003 16:19:20 Edited by - Grubbster on 13 Oct 2003 16:21:52 Link to comment Share on other sites More sharing options...
CharlesElliott Posted October 13, 2003 Author Share Posted October 13, 2003 Reading this again I think I may have cocked up more than I first thought (not unusual) but assume that I haven't done anything fatal given that I shut off at an indicated 100 degrees. Because I haven't got a heater I totally ignored all the info about backfilling as it seemed heater related. It appears that this is the best way to fill the head circuit and make sure that you at least get water following round the head. So when I first ran the car, I probably had very little water in the head and the thermostat didn't open at all . Assuming that the water thermostat gives and accurate(ish) reading of what is going on in the head circuit I hopefully avoided anything serious by shutting down before it got too much. Go on then, someone reassure me that I haven't done some fatal internal damage and warped the head or whatever happens when it overheats. Charles --- My Caterham Academy 2004 Diary Link to comment Share on other sites More sharing options...
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