nic.day Posted May 7, 2022 Share Posted May 7, 2022 So the back storyEngine got a little hot on the way home from Wales - went to 100 and the warning light came on. I stopped within 400 yrd, lucky there was a garage. No coolant in the header - topped up and got home with a steady 76 degrees - happy daysA couple of days later found it dame under the car and found a leak in the rad - that was repaired but still loosing coolant somewhereFound the o ring in the cap to have expanded so wont seal and loosing coolant while driving.New cap replaced and still loosing coolant - check every hose joint (even wrapped paper towel around each joint to check while on a decent drive - nothing!! all dry. But got home from this drive and expansion nearly empty (topped up before I left)I still have a little nagging doubt about the new cap (engine all dry though) - but other than that its a mystery. I seem to be using more coolant than petrol at the momentR500K series 2001 if that makes a difference Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 7, 2022 Member Share Posted May 7, 2022 If it's all dry externally ...What's the appearance of the coolant and the engine oil?How are you filling it and trying to make sure that there isn't any air left in there? What sort of thermostat do you have, and does it have the magic hole?Jonathan Link to comment Share on other sites More sharing options...
StevehS3 Posted May 7, 2022 Share Posted May 7, 2022 In addition to Jonathan's thoughts, I had a similar experience with my new Sigma. My logic was that if there wasn't any signs of obvious leakage it was escaping as steam through the expansion bottle cap. I swapped mine for a Gates RC246 which felt much better when I fitted it and solved the problem. The pressure rating is the same as the OEM. Link to comment Share on other sites More sharing options...
GulfSeven Posted May 7, 2022 Share Posted May 7, 2022 When I had HGF on my Elise (also K-Series), all the coolant came out of the exhaust... Link to comment Share on other sites More sharing options...
nic.day Posted May 8, 2022 Author Share Posted May 8, 2022 Hi JonathanCoolant is pink still as before I have flushed and cleaned the system - no milk shake in either the header tank or the oil catch tank - this is my biggest worry.I flushed and re filled then had a decent run and the header was almost empty, topped up again and another drive again nearly empty and again - I have the bleed T and followed my usual filling (no problems before)As for thermostat - no idea and again no idea about the magic hole!!! Link to comment Share on other sites More sharing options...
nic.day Posted May 8, 2022 Author Share Posted May 8, 2022 I am really hoping this is the fix - The old original o ring expanded and does not seal - local motorfactors had the right size but I am not sure if its sealing or holding pressure -I have emailed chris at redline to see if he has a proper one (waiting for a reply)Fingers crossed Link to comment Share on other sites More sharing options...
nic.day Posted May 8, 2022 Author Share Posted May 8, 2022 This is my biggest fear - but no milkshake at all so far in either the header or oil catch tank - but the coolant is going somewhereCould the head gasket go and I not see the mixing? Link to comment Share on other sites More sharing options...
GulfSeven Posted May 8, 2022 Share Posted May 8, 2022 It did on my Elise. No oil in the coolant or coolant in the oil, but all coolant magically vanished! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 8, 2022 Member Share Posted May 8, 2022 A hole drilled in the thermostat of Ks has two purposes: it allows the escape of air during filling even if the thermostat it closed, and it decreases the thermal shock from a large slug of cold coolant when it opens.It could be relevant to this problem if air is left in the system after filling.Jonathan Link to comment Share on other sites More sharing options...
john milner Posted May 8, 2022 Share Posted May 8, 2022 If the coolant is ending up in the combustion chamber I would have thought that there would be some steam or liquid from the exhaust and an engine that was running a bit different.If the coolant is getting into the lubrication system and staying there the oil level will rise.If the coolant and the oil are the correct colours it is most likely that the coolant has escaped from the engine system.My theory is the leaking rad caused temperatures to rocket which then deformed the cap/ring/bottle.If the car has a heater check that as it might not be such an obvious spot. My one developed a leak and was replaced with a tougher looking one from ebay Caterham 7 heater matrix.I had a leak on the hose that runs between the thermostat and the heater which took me a while to find. This run consists of two hoses joined together by a piece of plastic which was failing. I replaced the whole thing with a single replacement silcone hose (part number CHS120.5) bought with a club discount from SFS.The cheapest and easiest thing to try next is fit a new bottle and cap. At worst something is eliminated.Insufficient coolant plus an overheated engine and you could now have a warped head and HGF. Link to comment Share on other sites More sharing options...
nic.day Posted May 8, 2022 Author Share Posted May 8, 2022 Tim - I am starting to think this is it!! Just been out and had the car up to temp, reved it etc and coolant stayed where it was suppose to - watched the catch tank - lots of venting (is that normal?) with a little condensation.No leaks, coolant did not reach the cap, rad hot on one side and warm on the other, coolant flowing to the bleed tWhat pressure should the cap be? the new one says 16psi - no idea on the original.Temp got to mid 80s on tick over then up to 88ish, with a bit of revs came back to mid 80s and the fan came on at 81 as normal and stayed on. So got 5ltr of coolant coming and will take this with me to the fish and chip run, take it easy and top up as I go Link to comment Share on other sites More sharing options...
nic.day Posted May 8, 2022 Author Share Posted May 8, 2022 Thanks for this JohnWhen I topped up the coolant I also topped up the oil so expected more oil in the catch tank as it finds its level - I have had quite a bit of oil in the catch tank so this might be pointing to the HGF or I just overfilled the oil!!! but as I said no milkshake so it must be in the engine.The engine seems to be running fine though - on a cold start up just now, no water / coolant coming from the exhaust and I could not see steam. But there was a bit of venting through the catch tank - no idea if this is more than normal though.No heater so that rules that outI was under the car and I know the hose you mean - could not see anything though, but I guess it really needs load on the system to open any failings Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted May 9, 2022 Leadership Team Share Posted May 9, 2022 Deleted. Link to comment Share on other sites More sharing options...
nic.day Posted May 9, 2022 Author Share Posted May 9, 2022 thanks Stu Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 9, 2022 Member Share Posted May 9, 2022 "When I topped up the coolant I also topped up the oil so expected more oil in the catch tank as it finds its level - I have had quite a bit of oil in the catch tank so this might be pointing to the HGF or I just overfilled the oil!!! but as I said no milkshake so it must be in the engine."Chemical tests for products of combustion in the coolant are available, and probably more sensitive than the appearance.Jonathan Link to comment Share on other sites More sharing options...
revilla Posted May 9, 2022 Share Posted May 9, 2022 Long shot but ...On a K Series you can lose coolant into the combustion chambers through a leak in the inlet manifold gasket.There are coolant waterways into the inlet manifold at either end. Probabt not in use on throttle bodies other than as a bleed at the front, but still there on the head. If the gasket fails around either of the waterways it can leak internally into No 1 or No 4 inlet port, then be drawn into the combustion chamber without any external sign of a leak.You usually get discolouration of No 1 or No 4 spark plug when this happening, with pinkish whitish deposits.Worth a check. Link to comment Share on other sites More sharing options...
john milner Posted May 9, 2022 Share Posted May 9, 2022 Example of inlet gasket leakhttps://www.mycaterham.com/66828/66132.html Link to comment Share on other sites More sharing options...
nic.day Posted May 9, 2022 Author Share Posted May 9, 2022 Checked spark plug 1 and 4 but 3 was a little crusty compared to the others - and they seem ok but there was a little coolant around the inlet though - need to drain and then take the roller barrels off and check.Anything I should be worried about? not removed before Link to comment Share on other sites More sharing options...
revilla Posted May 9, 2022 Share Posted May 9, 2022 Obviously drain the coolant before starting.The other thing is, even if the gasket is OK, it probably won't be by the time you've got it off as they stick to the surfaces and come apart when dismantled. So have a new one ready.And .. on an R500, you've probably not got a standard Rover gasket. It will probably have the head ports matched to the throttle bodies and the standard gasket holes are too small and obstruct the airflow. Dave Andrews, DVA Power, a.k.a. oilyhands on here supplies modified gaskets to suit.Other that, it's really just a job of carefully unbolting them and putting everything back where it came from. Make sure you clean any old gasket material off both faces. Red Scotch Brite does the job, but don't get abrasive dust in the ports. You can stuff the ports with tissue and pull it out when you're done. Don't disturb anything on the TBs that you don't have to, just take them off whole, although you will probably need to remove the air filter and backplate for access. Link to comment Share on other sites More sharing options...
nic.day Posted May 9, 2022 Author Share Posted May 9, 2022 Good shout and thanks - had a good look today and the top bolts seem easy - how to get to the bottom ones is going to need double jointed small hands I guessWill give Dave a call and go get one from him so I am readyThanks again Link to comment Share on other sites More sharing options...
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