Percy TR6 Posted March 30, 2016 Report Share Posted March 30, 2016 Took the car for a 140 mile spin a week or so ago and it ran like a dream. Took it out yesterday and while it was still running fine, I noticed that the temperature gauge was up at the 4th white mark before I'd reached the end of the street. Today, I flushed the cooling system - was due anyway - and confirmed that water is flowing as I'd expect. I also ran the engine and noticed that the various pipes and thermostat seem to get warm as one would expect. I disconnected the gauge from the temp sender and it dropped to zero. I also checked the gauge with the ignition on, engine cold, and it rose - even though the engine wasn't running. The fuel gauge seems to be operating normally - I filled the tank prior to the last long run and it has dropped as expected. I noticed that there is a bit of something that looks like limescale around the temp sender joint - don't know how relevant that is. Given the above, any suggestions as the where to begin? My thoughts are that the temp sender is failing - is that a good place to start? Thanks, Steve Quote Link to post Share on other sites
john.r.davies Posted March 30, 2016 Report Share Posted March 30, 2016 (edited) Almost certainly the sender. Trouble is a lot of modern copies are very poor, and fail again quickly, but at £6.25 (Rimmers) you can't complain, although we should, and cheap to experiment. John Edited March 30, 2016 by john.r.davies Quote Link to post Share on other sites
Guest ntc Posted March 30, 2016 Report Share Posted March 30, 2016 Flushed the system? is the bottom of the rad getting hot? Quote Link to post Share on other sites
openroad Posted March 30, 2016 Report Share Posted March 30, 2016 Hi Steve, i have a very similar problem, i have tried different Guages and still read high....so have now tried two new but different senders.....one reads high, the other doesnt even reach a quarter on the guage....... i changed the thermostat, top hose , heater hoses all warm , so is the rad and the bottom hose slightly cooler, but i understand that that is always so.....engine is definitely not overheating. So what to do ? Find a sender that suits the guage ? I even tried a sender from another car that is always steady at about half way and that shot up towards the red !!! Have fun, Conrad. Quote Link to post Share on other sites
Percy TR6 Posted March 30, 2016 Author Report Share Posted March 30, 2016 Neil - the bottom of the rad is cooler than the top... Stay heats up first, then top hose, then top of rad, then eventually pipe from rad to pump warms a bit. I drained the rad & flushed with cold water, then rad flush then more water Why do you ask?? Conrad - are you getting your senders from the same source? Is there a recommended supplier? Steve Quote Link to post Share on other sites
Guest ntc Posted March 30, 2016 Report Share Posted March 30, 2016 At full working temp the rad should be the same temp as the top, why do you think there is always a debate as to where the fan sensor is fitted? granted the std fan is at the bottom but should make no difference,you need to vent the system or you have knacked the stat, also today you will find one sender fits all and do not believe on the colour banding. Quote Link to post Share on other sites
RobinTR6 Posted March 30, 2016 Report Share Posted March 30, 2016 Had this myself, measured them using one of those laser temp guns, anyway engine, head, rad etc not overheating but gauge had them very hot, ie 3/4 + on gauge. Anyway changed the new sender for another and problem gone. Quote Link to post Share on other sites
Percy TR6 Posted March 30, 2016 Author Report Share Posted March 30, 2016 Neil - see where you are coming from. I only ran the engine for 5 mins or so today & the rad was warming up at the bottom. The stat for the fan is located on the pipe from the bottom of the rad and until yesterday the fan was cutting in when the gauge showed higher than normal, so I think all is OK with that side of things. I'll get a new sender & see where it takes me. Thanks for your input. Steve Quote Link to post Share on other sites
openroad Posted March 31, 2016 Report Share Posted March 31, 2016 Hi Steve, the two new senders were from TR Enterprises, i was testing them out for them, i have reported back too.... It seems like they will work differently on different cars. ! Have fun, Conrad. Quote Link to post Share on other sites
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