charlie_pank Posted August 20, 2012 Share Posted August 20, 2012 Quoting gundersen: Quoting charlie_pank: I reckon you've got an air lock somewhere or your radiator is partly blocked.I don't know much about the persistence of air locks, but I have changed coolant three times (one time also changing all the hoses) while observing the problem. Of cause it might just be me doing it wrong, in which case I could change the coolant as many times as I want and still see the air lock Quoting Roadsport06: The cooling system is up to the job for a 140bhp k seriesAre you sure it is? I know of at least one other SV with exactly the same spec as mine which suffers from the same problem. Also a couple of answers in this thread suggests that the SVs might have a cooling problem. Quoting Roadsport06: so a fancy rad is surely a bit OTT.Well is a nice upgrade ever OTT? 😬 Quoting Roadsport06: Put in a new thermostatYou are of cause right, I could/should wait till I get the new thermostat from CC. Quoting Roadsport06: put in a bleed teeAlready done that Quoting Roadsport06: flush the rad (to check the flow isn't blocked)I will try that one, should be little extra work when I am fitting the new thermostat. As always, thank you for your feedback it is much appreciated! 😶🌫️ Air lock is caused by the combination of compromised design and failure to fill correctly. You haven't changed the design, so if you have an air lock it was caused by the way it was filled, if you filled it the same way each time there's no reason to expect the air lock wasn't re-created each time. There are far more powerful engines than yours (more power = more fuel burned per second = more heat) which are perfectly adequately cooled by the same radiator that you have... food for thought! Edited by - charlie_pank on 20 Aug 2012 12:10:26 Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted August 20, 2012 Share Posted August 20, 2012 Fit a PRRT and never worry about airlocks again Link to comment Share on other sites More sharing options...
charlie_pank Posted August 20, 2012 Share Posted August 20, 2012 I'm not really sure that I understand what a PRRT does, even after reading the wikipedia page. Can someone explain in simple terms? How does it eliminate airlocks? Where does the air go and how is it forced out of the places it is lodged in? Where does the extra water needed to fill the gap left by the expelled air come from? Link to comment Share on other sites More sharing options...
CageyH Posted August 20, 2012 Share Posted August 20, 2012 The PRRT forms a bypass loop parallel to the radiator (in simple terms). There is no thermostat in the J hose, so you don't get air trapped there. Normally it is installed vertically so air does not stay there. You still need to bleed the air out of the system, and keep the expansion tank topped up. The extra water would come from the expansion tank initially. Link to comment Share on other sites More sharing options...
charlie_pank Posted August 20, 2012 Share Posted August 20, 2012 I see. If there's an airlock somewhere other than the J hose, then it won't help. When I put my new (to me) engine in the car, the first time I ran it it had been sitting still for 2 years. It took a LOT of persuasion to fill the block's waterways and eliminate all the airlocks in the rest of the cooling system. It involved loosening strategic hose clips and squeezing pipes, tightening up the hoseclips in the right order, a bit of running without the expansion cap on and crucially, suspending the expansion bottle a few feet above the engine bay while filling it and running up to temp with the cap off. The whole experience drew me to conclude that normally when you just drain the coolant and refill with new, there are lots of places it doesn't come right out of, so you don't have the problems I did with the initial fill after a long (dry) lay-up. Edited by - charlie_pank on 20 Aug 2012 12:52:35 Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted August 20, 2012 Share Posted August 20, 2012 The PRRT was a doddle to fit and made it a doddle to fill the system. The temperature is also rock solid, the needle might as well be nailed to 82C Link to comment Share on other sites More sharing options...
CageyH Posted August 20, 2012 Share Posted August 20, 2012 Apart from when it is 42 degrees + outside, and you are stationary for a while. Edited by - CageyH on 20 Aug 2012 14:33:54 Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted August 20, 2012 Share Posted August 20, 2012 Reckon that would test any setup! I'd be parking up and cracking open a bottle of something cold 😬 Link to comment Share on other sites More sharing options...
charlie_pank Posted August 20, 2012 Share Posted August 20, 2012 Our 20 year-old hilux was fine in 50 degrees in the desert of Kazakhstan. The Jeep Cherokee we were with nipped a couple of the radiator pipes closed to fix a leak earlier in the trip and they were fine too! Link to comment Share on other sites More sharing options...
gundersen Posted August 20, 2012 Author Share Posted August 20, 2012 @Charlie: I am aware that much more powerful cars have gotten by with this cooling system, RJ has not neglected to point that out to me several times However seeing another SV with the exact same spec as mine having the exact same problem got me thinking, and perhaps most of the accumulated wisdom around here are based on S3's and not S5's. So perhaps the SV suffers from some kind of design flaw... Well I like the idea of the PRRT so I might just go ahead and fit one, also means I dont have to wait for the other thermostat to arrive Pop quiz: 1) How do I verify the presence/absence of air locks in the system? 2) How much water is a radiator supposed to flow? Just so I know what to look for when testing it with the garden hose. Link to comment Share on other sites More sharing options...
Fil M Posted August 20, 2012 Share Posted August 20, 2012 My SV's needle gets higher in the hot weather and the fan kicks in a bit more often. Assuming the radiator is the same as an S3 (i am sure it is) then there must exist a wider gap around the rad formed by the wider nose cone thus reducing the air flow through the rad .... comp;ared to an S3. There may lie the issue if there is one. Otherwise the cavernous bonnet 😬 gives more air space so should be cooler unless this issue reduces the effect. If you see what I mean Link to comment Share on other sites More sharing options...
charlie_pank Posted August 20, 2012 Share Posted August 20, 2012 Quoting gundersen: @Charlie: I am aware that much more powerful cars have gotten by with this cooling system, RJ has not neglected to point that out to me several times However seeing another SV with the exact same spec as mine having the exact same problem got me thinking, and perhaps most of the accumulated wisdom around here are based on S3's and not S5's. So perhaps the SV suffers from some kind of design flaw... Well I like the idea of the PRRT so I might just go ahead and fit one, also means I dont have to wait for the other thermostat to arrive Pop quiz: 1) How do I verify the presence/absence of air locks in the system? 2) How much water is a radiator supposed to flow? Just so I know what to look for when testing it with the garden hose. There might be one or two other SVs with the same problem but if there's even one that doesn't then it's not a design flaw causing your problem. It is however notoriously difficult to fill the cooling system and perfectly possible that 2 people have air locks... My suggested method for clearing them is to unbolt the expansion tank and hang it from the garage ceiling a couple of feet above the engine bay with the lid off. Turn on the heater and loosen every hose clamp you can find. Undo the bleed screw of the radiator. Now squeeze each tube to force coolant out of each joint. Work from the lowest point to the highest, tightening each clamp and the bleed screw once only water is escaping, no coolant. Once that's done, run the engine for as long as you dare wit the expansion tank's lid off and the tank still suspended. Keep topping up as necessary, once you're done switch off the engine.and close the tank lid. Link to comment Share on other sites More sharing options...
johnpbransfield Posted August 21, 2012 Share Posted August 21, 2012 This may be of interest. Coming back from a trackday last week i noticed my temp reading was 100c, it is usually high 80c. I got home OK (150 miles) but was concerned it would go into the red which it didn't. Thought it may have an airlock so i did all the usual things but the fan was still not kicking in until 100c.When it was cold and i turned the ignition on but did not fire the engine upI noticed that the needle on the temp guage went straight to 60c. A coleague informned me that it would be a faulty sender (single wire on the water rail). I put a new one on to day and the problem is solved. Fan now kicking in at mid 80c and the the guage is reading zero with the ignition turned on. Could be that your car is OK and that 100C is the new 80c!!! hope this helps Link to comment Share on other sites More sharing options...
gundersen Posted August 21, 2012 Author Share Posted August 21, 2012 @Charlie: Thank you for the filling procedure, I might give it a try next time I refill. Last time I used Stu's method from here, just using a bleed tee instead of filling through the heater hose. Is there a way that I can tell if I have an airlock or not? @John: Thank you for the information, as far as I have gathered the coolant temp sensor and electrical oil pressure sensor are notoriously unstable so it was a good bet. However, I have verified that the ECU coolant temp sensor and the dash temp sensor agrees on the temperature, so it is unlikely that this is the cause here. Link to comment Share on other sites More sharing options...
patneale Posted August 21, 2012 Share Posted August 21, 2012 This seems to be getting out of hand. The simple answer is that the standard radiator in a Xpower 140 1.8 K series. is totally fit for purpose. My SV ( 45,000 miles) has never over heated and it has been provoked. Genoa to Montpelier at 80/85 MPH cruising at 35C caused no more than 95C on the gauge. Half an hour in a jam in the motorway tunnels of Basle with 45C outside temp caused no more than 95C with fan running the whole time. 5 minutes foot on the floor south of Reims at between 6500 to 6750 RPM in 6th at 25C had the temp steady at 90C and oil 5 bar. The only issue is that the fan operated a lot in the town traffic in warm weather. Simon Lambert told me not to worry it would not overheat and it hasn't. BUT not liking the fan operating so much I made up little "wings" which fill up the gap on the outside of the radiator and the nosecone so that the air would not escape around the sides. Problem solved. C.C. say that when you fill the car with water ( antifreeze change)it is essential to raise the front of the car by at least a foot i.e trolley jack plus axle stands and massage the hoses to expel air. The old Rover dealers procedure in Rover cars with this engine was to pressure fill as the cylinder head is where the air lock normally forms. The C.C. method works. A good test for an airlock is to make sure that the water is up to the mark, start the engine and run to 80C then take the cap off the expansion tank. Let the engine idle and leave until the fan starts and the whole system is hot. The water will not overflow from the tank as there will not be any need for the system to be pressurised at tick over. IF HOWEVER the cylinder head has an airlock the water will start to boil in the head and steam will form and there will be a minor eruption of water out of the tank as it vents. If you have an airlock and you drive the car with the cap on the tank it will pressurise as normal, but as the head is not being cooled properly the water in touch with this area will be much hotter than normal and this will cause the temperature gauge to show anything up to 110C. I have been there when I changed the antifreeze and had 3 attempts to get rid of the airlock and called C.C. Using the jacking up the front method worked perfectly. I repeat.. the NORMAL RADIATOR IS FIT FOR PURPOSE. If that does not cure it then there may be an issue with the head gasket. Of course it might be the temp sender. ( I have had a new one (and 5 oil pressure ones...3 as warranty claims since cured totally by remote sender fitting)) Coming back from St Moritz run in 2005 the oil pressure went to zero up the Grimsel Pass and later the temp went past 120C into the black(all fluid levels normal.) The engine was running sweeter than ever so I disconnected both gauges to save worrying and called into Caterham for new senders on the way home and all was normal when fitted the next morning !! Link to comment Share on other sites More sharing options...
gundersen Posted August 21, 2012 Author Share Posted August 21, 2012 Hi pat, thank you for your input It seems we have the same car (SV) and engine, so your points a valid. However, I have not seen any temperature issues either in the conditions you describe, so for all you know you might have the exact same problem At normal and heavy road use my temperature is rock solid at 90 degrees for coolant and about 80 for oil, it is only when used on the track that this problem presents itself. It is very unlikely it is a sender issue, as I have two senders reporting the exact same temperature (within one degree at 89/90). Regarding the filling procedure, it seems that there is as many ways of doing this as there are sevens And without a surefire way of verifying the existence/non-existence of air locks I feel that I am fighting an uphill battle trying them one-by-one and having to wait for the next track day to see if it have had any effect. I will try your method (running it up to temp without cap and looking for air bubbles) and see if that provides new information. Link to comment Share on other sites More sharing options...
Fil M Posted August 22, 2012 Share Posted August 22, 2012 as per johns post above ... my temp sender is recently higher and jumps when ignition on at cold .... my sender (not very old) is beginning to play up already ...luckily I have enough for this persistnet problem in the garage bench drawer! Link to comment Share on other sites More sharing options...
CageyH Posted August 22, 2012 Share Posted August 22, 2012 Didn't Grubbster have a confusing issue recently, which only manifested itself on track days? Link to comment Share on other sites More sharing options...
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