Orange Posted March 23, 2020 Share Posted March 23, 2020 I have an 1800 k series with a recently fitted Radtec radiator. There is now slightly strange cooling issue.If I start it let it warm up, it gets hot as normal up to about 80 deg on temp gauge, thermostat opens normally and water circulates to cool. Thermostat then opens and car cools. All pipes get hot. Then thermostat closes.Then temperature climbs to just under 100 deg but no higher. However if I rev it, thermostat opens and cools to about 80 deg but then temp raises again to just under 100 deg.The problem seems to be that the thermostat does not open unless I rev it but having said that it opens fine the first time on the heating cycle.Any ideas? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 23, 2020 Member Share Posted March 23, 2020 Didn't happen with the old radiator?Reasonably sure that there's no air in there?What coolant?I think that I'd swap the thermostat and see what happens. And have a good play with the existing one with a couple of pans containing hot and cold water.Jonathan Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 Thanks, thinking it is thermostat myself but trying to avoid taking it apart initially.Coolant is Comma G30 premixed.It did this before with the old radiator but was less pronounced. I.e temperature dropped slightly when accelerating but otherwise fairly steady mid 80s temperature.I have been reading about the jiggle valve in the manifold and wondered if this could be the cause and I have some air in the system that I cannot bleed out (I have not seen any water return back to the expansion tank and this stays cold. Sound normal?Martin Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 23, 2020 Member Share Posted March 23, 2020 ... and I have some air in the system that I cannot bleed out...Which methods have you tried so far... jacking, massaging, extra bleeding T piece?Jonathan Link to comment Share on other sites More sharing options...
revilla Posted March 23, 2020 Share Posted March 23, 2020 It's not a triple pass race type radiator is it by any chance? I saw exactly these symptoms with one of those where the water pump just couldn't circulate enough water through the extra resistance of the radiator at idle. Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 Yes all of that. I am sure I have all of the air out of pipes etc and the radiator. If I open the bleed tee or radiator bleed coolant comes out.i am going to try jacking it higher and rebleed before taking it apart.Is this just normal K Series nightmare bleeding do you think or dodgy thermostat. The thermostat was replaced last year just after I bought the car as I discovered that the previous owner had removed the thermostat completely meaning that the car took ages to warm up.Martin Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 Radiator is the standard Radtec, not triple pass as car will be mainly used on the road. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 23, 2020 Member Share Posted March 23, 2020 Andrew: Please check Private Message.ThanksJonathan Link to comment Share on other sites More sharing options...
7SW Posted March 23, 2020 Share Posted March 23, 2020 Hello, I've added a bleeding T at the higher position of the circuit: no trouble to bleed the circuit since and without having to level up the front of the Cat Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 Thanks, my car already has this. When I refilled the coolant, it came out of this tee first and then out of the radiator bleed screw. I thought I got all of the air out but now I am not so sure.....Thanks anyway, any suggestions welcome and appreciated! Martin Link to comment Share on other sites More sharing options...
Fyldeflier Posted March 23, 2020 Share Posted March 23, 2020 I had very similar symptoms on my K series car.Turned out to be the pressure relief cap. They are known to be unreliable.worth a try.John. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 23, 2020 Member Share Posted March 23, 2020 Following Andrew's thoughts in #5 above I wonder if a failing water pump could do this, not enough oomph at idle...But I'd start with the simple stuff. Jonathan Link to comment Share on other sites More sharing options...
SM25T Posted March 23, 2020 Share Posted March 23, 2020 Are all the hoses getting equally hot ? If you have a heater, this is a classic place for an airlock. Any hose cooler than the others once up to temperature will show you the airlock . Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 Thank you for your suggestions, if the cap is faulty does it simply not let any pressure build?I hope it is not the water pump, that is also new last year! Is there any way of testing this without removal?Martin Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 Yes all hoses get hot when revved but then bottom hose goes cold once thermostat closes and appears reluctant to reopen unless revved again.Does the thermostat rely on pressure to open?Martin Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 23, 2020 Member Share Posted March 23, 2020 Does the thermostat rely on pressure to open?Not normally. That's why you can test them with two pans of water.Jonathan Link to comment Share on other sites More sharing options...
SM25T Posted March 23, 2020 Share Posted March 23, 2020 Is it possible you have fitted the stat back to front ? So the sensing bit is not in the hot water. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 23, 2020 Member Share Posted March 23, 2020 I hope it is not the water pump, that is also new last year! Is there any way of testing this without removal?Sorry, I don't know.Don't get too alarmed by this, but:Why was it replaced?Does the new one have have a plastic or a metal impeller?Jonathan Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 I don't know, water pump was replaced by GP Sevens at the same time as the Cam belt and thermostat by Nick Potter...I would like to think that they would use quality parts and know which way to put a thermostat in!Can you even put it in the wrong way around? Link to comment Share on other sites More sharing options...
Wrightpayne Posted March 23, 2020 Share Posted March 23, 2020 I dont think its possible to fit the stat the wrong way around. Drilling a hole in it (highest point when installed) helped my issues along with raising and filling slowly via the bleed tee in the heater loop. Link to comment Share on other sites More sharing options...
Area Representative paul richards Posted March 23, 2020 Area Representative Share Posted March 23, 2020 Stat won't fit wrong way round. Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted March 23, 2020 Leadership Team Share Posted March 23, 2020 Probably air in the system. I agree with Wrightpayne, 3mm hole in the stat at the top, then to refill ...Expansion tank cap and top plug on radiator removed, then fill slowly (very slowly) via the bleed T in the bypass/heater circuit, holding the T as high as you can and definitely higher than the expansion tank. When coolant comes out of the top of the radiator fit the plug. When the expansion tank is up to level fit the cap. Keep filling via the bleed T until you can't get any more in then fit its' cap. Job done, works every time.Don't mess about raising the front and trying to fill via the expansion tank, it doesn't work and you'll still have air in the system.Stu. Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 Thank you, general consensus seams to be that I still have air in the system. I will empty it and try again via the Tee this time.Martin Link to comment Share on other sites More sharing options...
Orange Posted March 23, 2020 Author Share Posted March 23, 2020 The more I think about this the more I think I may have a problem with the thermostat. I think I will buy a new one anyway before I drain it down so that I can test the old one and replace before refilling. I am wondering if it is not operating but when revving it is forced to open.Please can somebody confirm the part no. to me. Is it PEL10016 and 88 degree rating? Any particular make recommended or online place to buy one? Thanks in anticipation Martin Link to comment Share on other sites More sharing options...
SM25T Posted March 23, 2020 Share Posted March 23, 2020 I changed from 88C to 82C on my 1.8 k-series Link to comment Share on other sites More sharing options...
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