Fallon Posted June 25 Share Posted June 25 My 1996 K series Super sport is overheating. I have been on a couple of short trips, 20 mins sort of thing, and the temp has just gone up and up for both oil and water so much so that the needle is hard over to the right in the red zone. (it did it once then went away but has come back again) The engine on both occasions has sounded absolutely fine and even when turned off no "creaking" from overheating etc The water in the top pipe to the radiator is very hot while the bottom pipe is relatively cool (warm to the touch) so I'm not sure coolant is circulating?? Can I tell if it is from watching the resevoir or how would I check circulation? The Radiator fan has not cut in and appears to have a little green corrosion on plugs which I gave a brief clean up too but the fan still did not kick in. I'm mechanically/electrically fairly competent but not on engines (completely clueless) so I'm not sure if what should be doing what and what controls what (if you get my drift). I would imagine the water pump runs off a drive from the engine so is always on? Is there thermostat controls that direct the water flow using valves? Is there a thermostatic control for the fan? Any help or guidance on what to check would be gratefully received Link to comment Share on other sites More sharing options...
SM25T Posted June 25 Share Posted June 25 Probably an airlock in a hose, top of radiator or heater. Once warmed up, all hoses should be roughly equally hot. Link to comment Share on other sites More sharing options...
SM25T Posted June 25 Share Posted June 25 The fan is probably switched by a thermo switch in the top of the radiator. If there is air in the top of the radiator header, switch won't operate. Test the fan by removing connectors from thermo switch and touching connectors together with ignition on. Fan should run. Link to comment Share on other sites More sharing options...
Wrightpayne Posted June 25 Share Posted June 25 Was it performing differently (normal) previously? Have you had any work done? If yes and no, sounds like coolant loss somewhere or a stuck thermostat. Take the allen plug out of the top of the rad - can you see the tops of the cooling fins (assuming original copper cored rad) top up via the plug till brimmed and monitor. If draining the K series coolant do a search of the archives - they are a bit finicky to refill! Link to comment Share on other sites More sharing options...
Fallon Posted June 25 Author Share Posted June 25 Thank you guys This is my Saturday morning plan in place appreciate the guidance, I'll let you know how I get on 😁 Link to comment Share on other sites More sharing options...
gin-fizz-whizz Posted June 26 Share Posted June 26 A similar thing happened to me after changing the hoses which made us think it was an airlock but it turned out to be a sticking/faulty thermostat 1 Link to comment Share on other sites More sharing options...
Fallon Posted June 29 Author Share Posted June 29 Started her up this morning to work on sorting this problem 1st thing I checked was the fan worked by shorting the switch at the top of the Rad (as suggested by SM25T 👍) The fan work fine when I did this. I only had her running on tick over but noticed after only a minute or so the temp quage on water was approaching the red and oil was 40 degrees behind but heading in the same direction. I connected the fan to force it to run but this did not effect the temp. I turned her off and looked for the possible air lock as suggested by Wrightpayne and Gin fizz whizz 👍, the top of the rad was full and so was the highest point on the heater box, see pics1 & 2. Checking the hoses, some are hot some are not. Everything between the radiator, through the top heater and down to a Black plastic unit on the side of the engine (see pic 3) is hot The hoses from this black unit to the bottom of the Rad are cool. When the engine is running I don't see any obvious signs of water circulating (never having looked I'm not sure if you should though to be fare) I'm not sure what this black unit is? is it a valve controlling flow of water or the pump possibly? Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted June 29 Area Representative Share Posted June 29 Black unit is thermostat housing. Cold bottom hose indicates thermostat not opening. This could be a faulty thermostat or an air lock. I’d be tempted to drain coolant and remove thermostat and change it and at the same time put a small hole in the thermostat to aid bleeding. Lots in the forum archives on this subject. 1 Link to comment Share on other sites More sharing options...
Fallon Posted June 30 Author Share Posted June 30 On 29/06/2024 at 14:11, Paul Richards said: Black unit is thermostat housing. Cold bottom hose indicates thermostat not opening. This could be a faulty thermostat or an air lock. I’d be tempted to drain coolant and remove thermostat and change it and at the same time put a small hole in the thermostat to aid bleeding. Lots in the forum archives on this subject. Thanks Paul, I think I am going to replace the thermostat as you suggest but have now discovered the relocating of said Thermostat to the Hot side of the Radiator (at the top) as being a good modification as it helps with bleeding etc. There appears to be some fairly clear instructions and on how to do this on the forum and beyond but nobody mentions what to do with the bottom hoses where I will remove the current Thermostat from. The hoses are different sizes. Do I just get a reducer fitted between them to make the connection? Aslo I think I need to fit an 82 Degs thermostat rather than 92 Degs. Does this sound correct? Link to comment Share on other sites More sharing options...
Englishmaninwales Posted June 30 Share Posted June 30 (edited) On 29/06/2024 at 09:11, Paul Richards said: Black unit is thermostat housing. Cold bottom hose indicates thermostat not opening. This could be a faulty thermostat or an air lock. I’d be tempted to drain coolant and remove thermostat and change it and at the same time put a small hole in the thermostat to aid bleeding. Lots in the forum archives on this subject. From my experience this is likely to be an air lock. I’ve had that several times over the last 20 years and never had a failed stat. You can remove the stat and fit a top hose stat as you suggest - QED supply a kit, if slightly expensive and requires correct plumbing of it’s bypass hose, but it works fine and makes coolant refills much easier. Thr bottom hose is unchanged, plumbed from the radiator to the existing black stat housing. The original stat is removed and replaced with a steel ring, comes with the QED stat kit. 82 deg stat is just fine. Malcolm Edited June 30 by Englishmaninwales 1 Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted June 30 Area Representative Share Posted June 30 (edited) What Malcolm says is spot on. If you do decide on a QED top hose thermostat do connect to the hose on the bottom of the expansion tank and not the small top hose. See my earlier thread on Blatchat HERE. Details of top hose thermostat and instructions HERE Edited June 30 by Paul Richards Link to comment Share on other sites More sharing options...
Fallon Posted July 1 Author Share Posted July 1 Thanks guys much appreciated I think I will research clearing air locks first before I buy the Thermostat upgrade if only to understand how to do this properly prior to doing the bigger job. Link to comment Share on other sites More sharing options...
SM25T Posted July 1 Share Posted July 1 A small hole in the base plate helps allow air past the thermostat. It must be at the top when fitted. See photo Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 1 Member Share Posted July 1 11 hours ago, Fallon said: I think I will research clearing air locks first before I buy the Thermostat upgrade if only to understand how to do this properly prior to doing the bigger job. That's what I'd do first: • Check that the thermostat is of the rating that you want and working. • Then fill without air locks. This may include jacking up the nose, opening the heater valve, adding a bleeding T-piece, massaging the hoses and feeling and understanding the temperature changes. With that approach mine and many others start to behave themselves, and may not need the hole in the thermostat plate, as above. But I'm not aware of any downside in doing that, and if you're taking the thermostat out anyway... Jonathan Link to comment Share on other sites More sharing options...
Mick Day Posted July 1 Share Posted July 1 When I drilled a hole in the thermostat it took much longer for the engine to get up to working temperature. K series with 82 deg stat. Link to comment Share on other sites More sharing options...
SM25T Posted July 1 Share Posted July 1 It's only a 3mm hole. My 1.8 with an 82C thermostat warms up pretty quickly Link to comment Share on other sites More sharing options...
Seabea23 Posted July 1 Share Posted July 1 Yes, a small 3mm hole and refill the system gradually. Mine warms up normally. Link to comment Share on other sites More sharing options...
Fallon Posted July 5 Author Share Posted July 5 Just drained the system and removed the Thermostat. When tested it did open at its set temperature 88 degrees. I thought it would open more but then the water out of the kettle once in the jug was about 90 degrees so I guess it's fine. I'm minded to refit it as the engine was fine before rather than getting an 82 degree replacement. The 3 mm drill waiting to do its job is on hold as my Thermostat looks a little different to that pictured above. It has a small brass gizmo like a rivet that is loose in the hole, I'm tempted to just remove it and leave the hole there as my now already supplied 3mm drilled hole. Does this sound the right thing to do? Does anyone know what the Gizmo/rivet thing is? Link to comment Share on other sites More sharing options...
SM25T Posted July 6 Share Posted July 6 If it is loose in the hole, and at the top when fitted to the car, it is doing the same job, letting any air pass through Link to comment Share on other sites More sharing options...
Fallon Posted July 7 Author Share Posted July 7 All done but problem persists, getting a replacement thermostat Out of interest how do I check if the water pump is operating correctly? Seems a bit clumsy to just remove a hose and see if coolant sprays out Link to comment Share on other sites More sharing options...
Miker7 Posted July 7 Share Posted July 7 Where abouts in the country are you? I'm wondering if there is someone local who could pop round and offer moral support & maybe help. Link to comment Share on other sites More sharing options...
Fallon Posted July 7 Author Share Posted July 7 I'm just north of Coventry, however.... Had a break through this afternoon. Tried bleeding the system one more time and managed to coax out a few more bubbles. I also noticed while pulling pipes around a hose that one joint was passing a little and when I tightened the Jubilee clip it failed (wrang the neck of it sort of thing) I then tried the engine again and it held temperature perfectly. I am going to order a new set of Jubilee clips and replace them as the pipe work seems to be in good condition. I'll give it a couple of more tries in the coming days and a road test and hopefully be able to report back all is well! Link to comment Share on other sites More sharing options...
SM25T Posted July 7 Share Posted July 7 Mikalor hose clamps are nicer than jubilee clamps. Sounds like you might have found the problem. Link to comment Share on other sites More sharing options...
OldAndrewE Posted July 7 Share Posted July 7 Beat me to it Buy Mikalor Stainless Hose Clamp | Demon Tweeks (demon-tweeks.com) Link to comment Share on other sites More sharing options...
Fallon Posted July 7 Author Share Posted July 7 Cheers guys! They look a much better job than a standard jubilee clip. Link to comment Share on other sites More sharing options...
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