c7ollie Posted May 21, 2014 Share Posted May 21, 2014 Rover K series 1.8 165bhp Head gasket good according to garage pressure test and no sign of mayo in engine. Replaced thermostat now with a 2mm hole in. Refilled coolant Test drive resulted in progressively increasing temp. Stopped, expansion tank full and no sign of coolant at the bleed tee by the heater. Drained coolant down to max level by draining from the top of the radiator put the caps on and then topped back up at the bleed tee. Ran the engine with bleed tee cap off to get rid of bubbles. 10 minTest drive this time spot on never got passed 88oC at 30mph or 100. hurrah. Pulled up at home left the car running for 5 mins to see what would happen. Temperature kept rising fan came on temp kept rising and the expansion tank filled to bursting point. Again, no coolant in the pipe at the bleed tee! What am I missing here? All help appreciated. Ollie Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted May 21, 2014 Share Posted May 21, 2014 Was heater turned on when you filled it ? Sure you have an airlock in there. Link to comment Share on other sites More sharing options...
c7ollie Posted May 21, 2014 Author Share Posted May 21, 2014 Lever was out but the fan wasn't on. Link to comment Share on other sites More sharing options...
c7ollie Posted May 21, 2014 Author Share Posted May 21, 2014 Perhaps I just need to repeat what I have done a couple more times to work the airlock out? Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted May 21, 2014 Share Posted May 21, 2014 I mean valve open ...... not fan runnng. Link to comment Share on other sites More sharing options...
c7ollie Posted May 21, 2014 Author Share Posted May 21, 2014 I didn't realise the valve wasn't completely open on first fill but definitely fully open on the second top up. Link to comment Share on other sites More sharing options...
CliffC Posted May 21, 2014 Share Posted May 21, 2014 When you start up,from cold does your coolant system pressure up prior to the temperature rising? If you run your heater does the blower temperature run hot then cold ? Link to comment Share on other sites More sharing options...
c7ollie Posted May 22, 2014 Author Share Posted May 22, 2014 The heater blows hot no cycling of hot/cold but I didn't specifically check - will do. How do you check that the pressure builds before getting hot and should it or not? I could see the water circulating through the bleed tee but I think that was because the engine was still quite hot and therefore the thermostat was still open. Thanks for your help. Link to comment Share on other sites More sharing options...
Klunk Posted May 22, 2014 Share Posted May 22, 2014 Bit of a daft one this one, but the rad fan is running the right way when it kicks in? I.e. Not trying to cool the engine with hot engine bay air. I managed to wire the fan in reverse ( ) on a rebuild and it exhibited exactly the same symptoms. Regards, Giles Link to comment Share on other sites More sharing options...
revilla Posted May 22, 2014 Share Posted May 22, 2014 You've got hot water flowing past the bleed tee and the heater is blowing hot, so that rules out an airlock in the heater or bypass circuit preventing proper circulation. The fan is kicking in, and the fan is driven by a thermoswitch on the radiator, so it appears you must at least have some flow out to the radiator, which would mean there must be some flow back through the thermostat, but it is drilled so will allow a litle flow even when closed. Is the bottom return hose from the radiator back to the thermostat getting properly hot (too hot to hold your hand on it)? If not, it would suggest a thermostat problem, either air trapped around it insulating it from the hot water and preventing it from opening (unlikely if you've drilled it), a faulty thermostat or possibly the thermostat fitted back to front. Are you 100% sure you fitted the thermostat the same way around as it came out? If it is getting hot, then I would say that water is flowing where it should and should be keeping the temperature under control. The fact that it isn't and the fact that you are clearly getting gas of some sort into the cooling system (which you are finding behind the bleed tee, and which is displacing water out into the header tank) suggests a head gasket problem, despite the pressure test results. I would look at getting a "sniff test" done which will identify combustion products in the coolant, which will tell you decisively. Either get a garage to do it, or you can buy cheap and easy DIY kits on eBay. That will tell you one way or another. Head gasket failures are generally a failure to keep combustion gases, oil, water and outside air separated from each other. Depending upon where it fails you can get mayonnaise (water in the oil) but this is not necessary - for example failure around a fire ring may just release combustion gases into the coolant under some combinations of temperature and load, giving symptoms very much like yours, without any possibility of oil in water or water in oil. For comparison, the temperatures you quote when yours appeared to be "normal" still seem very high to me. At idle mine (1.8K VVC) won't go much above 80C and when driving it actually drops a bit due to the cooling air flow over the radiator. It never goes anywhere near 100C, whatever I do to it. Link to comment Share on other sites More sharing options...
c7ollie Posted May 22, 2014 Author Share Posted May 22, 2014 Giles - Thanks, i'll check it, I had a short in the fan circuit which the Garage fixed during MOT and service. I'll check it, you never know. Not a silly suggestion,I would try Alt, Ctrl Delete if I knew it would fix it. Revilla - Brilliant info thanks. You've got me thinking about the thermostat being the wrong way round but from memory I'm quite certain that the plastic housing would only allow it one way round - I certainly put it in the way round that looked most obvious with a match shaped recess. FYI I also made sure that the hole in the thermostat was not obstructed because if you put it in say 3 o' clock rather than 9 o clock, part of the inside of the black plastic enclosure obstructs the hole. After the second run where the temp remained constant 88 but started to overheat on idle, I checked the pipe between Thermostat and radiator and it was warm (but not cold) in comparison to the other pipes which were hot. ?? Thanks for your help. Link to comment Share on other sites More sharing options...
c7ollie Posted May 22, 2014 Author Share Posted May 22, 2014 FYI mine is factory built on a 52 plate and has always run with the temp needle inexactly the same place just above the 80 which I call 88 (long live analogue dials - not! ) I have tracked it 20 ish times, Nurburgring 5 times, Spa etc etc so I'm not too worried so long as it doesn't overheat on idle. I think the answer to this still lays in and around the thermostat? Link to comment Share on other sites More sharing options...
revilla Posted May 22, 2014 Share Posted May 22, 2014 The return flow from the radiator is normally a bit cooler than the hot water flowing into it from the head if the radiator is doing it's job, but it's normally still very hot to the touch. If yours is only warm as you say, it does sound like you haven't got full flow through the radiator. If I were you I would take the thermostat out and test it in a pan of hot water (plenty of info on here on how). If any doubt, replace it as they are not expensive compared to what may be damaged if they fail. Then make sure it is fitted correctly and refill from the bleed tee VERY VERY slowly, allowing any air to escape. Then see how it goes. My technique is to remove the expansion bottle cap and radiator bleed screw then fill using a very slow trickle from the bleed tee. When it starts to flow out of the radiator bleed, refit it then keep filling slowly. When it reaches the right level in the expansion bottle, put the lid back on and keep filling slowly from the bleed tee until it won't take any more. Make sure you have lifter the bleed tee up to be the highest point in the system while filling. Link to comment Share on other sites More sharing options...
Wrightpayne Posted May 22, 2014 Share Posted May 22, 2014 Wot he said most type faster!! It is impossible to get the t-stat the wrong way around. In theory the bottom radiator hose should be a lot cooler than the top one if the rad is doing what it should. I had a similar experience when I changed the coolant for the first time. I drained and refilled using the advice on here and it was fine. Done it several times since and never had a problem. Ian Edited by - Wrightpayne on 22 May 2014 11:52:02 Link to comment Share on other sites More sharing options...
Nick Woods Posted May 22, 2014 Share Posted May 22, 2014 If you take the car for a run and the expansion tank is still overfilling, let it cool then undo the radiator bleed nut (on top of the rad). If you get gas rushing out and the level in the header goes back to normal (ie what it was before you started the engine) then you might be looking at the early signs of head gasket failure. If you can repeat this scenario over and over again I'd say its almost certainly the gasket, and will be caused by gases leaking past it into the coolant, causing it to overpressure and pushing up the level in the header. The gases will then accumulate in the pipes and/or the top of the rad, giving the impression they are empty. If the above is not repeatable in this way then there may be some other cause such as an airlock Mine did this but it took a long time to realise that it was gasket failure, because none of the other indicators such as 'mayonnaise' or tests for gases in the coolant were present. Mine only did it when the car was being driven fairly hard , presumably because the pressures on the gasket were higher. See here for the full story Edited by - Nick Woods on 22 May 2014 12:35:55 Link to comment Share on other sites More sharing options...
CliffC Posted May 22, 2014 Share Posted May 22, 2014 My head gasket had failed causing the issues of cycling the heater hot and cold and also after only 2 mins running from cold if I opened the bleed T slowly, coolant would begin to escape. Normally this happens when the coolant is hot but not after 2 mins from cold *nono*There were exhaust gases entering the coolant system and pressurising it. Link to comment Share on other sites More sharing options...
TomGaval Posted May 22, 2014 Share Posted May 22, 2014 Had a very similar issue. Pressurized coolant, no mayo, no white smoke, water temps stayed normal. Oily guessed breached fire ring. Pulled head, did the peening, skim and new dowls, head bolts and gasket. All good now. Good luck. Tom Link to comment Share on other sites More sharing options...
Englishmaninwales Posted May 22, 2014 Share Posted May 22, 2014 Quoting TomGaval: Had a very similar issue. Pressurized coolant, no mayo, no white smoke, water temps stayed normal. Oily guessed breached fire ring. Pulled head, did the peening, skim and new dowls, head bolts and gasket. All good now. Good luck. Tom Same symptoms and cure as my 1800 supersport. Link to comment Share on other sites More sharing options...
c7ollie Posted May 23, 2014 Author Share Posted May 23, 2014 Ran out of time last night, had to go to the pub! but I had time to see that overnight the coolant level in the expansion tank had returned to normal, coolant came out of the top of the rad when I checked but no coolant at bleed tee. (No fluid on the floor). If gas was getting in, the coolant would displace but it wouldn't disappear so I have to assume there wasn't enough in there in the first place ie and airlock. Therefore I am assuming that the airlock has now moved to the highest point. I put in 1/2l more coolant (v slowly) until full, including pulling the pipes high so that the coolant filled the heater as well and then left it over night to settle down. I'll test drive over the weekend and if this doesn't solve it, I will pursue head gasket with all the info provided. Thanks. Link to comment Share on other sites More sharing options...
c7ollie Posted May 24, 2014 Author Share Posted May 24, 2014 I bought a new expansion tank cap for the hell of it as well but everything now is just dandy, it was only an airlock (I think) Thanks for all the help. Link to comment Share on other sites More sharing options...
revilla Posted May 24, 2014 Share Posted May 24, 2014 Great news, hope it continues 😬 Link to comment Share on other sites More sharing options...
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