Replacing Thermostat

[thetyrant]

The fans should be coming on above 93 C, so if the chart is correct, the fans should be running continuously.

The thermostat should start opening at 80-84C and be completely open at 90C, so I would expect the normal running temp to be in the 90C range.  I know on ours the temp gauge shows in the middle, but as soon as it goes above the middle the fans come on.  This happens quite often on a hot day when stopped

Yes the fan runs continuously but has very little effect on temperature numbers as the coolant isnt actually circulating through the radiator, it looks to be pointing to towards sensor or wiring issue at moment as other than the high reading car behaves perfectly and has done so since i bought it. Hopefully change the sensor tonight for my spare see what happens.

Ian

[thetyrant]

OK i think we have a winner!

Changed the coolant temp sensor for the spare from my old celica, its a used sensor but was working ok  in Celica and i just changed it out while trouble shooting another issue on that car, luckily i didnt throw it away as was able to use it for this test on the roadster

40 minute test drive later and once warmed up the car is sat pretty much constantly at 89-90c no matter if i was cruising, sat idling in traffic or giving it some boost!, couple of times it nipped upto 92c but never went any higher soon dropped back down to 90c, coolant was circulating through the rad when i checked at 92c so all seems good to me.

Ive never seen a coolant sensor do this sort of failure, as in just reading around 8-10c higher than actual coolant temp but otherwise giving readings you would expect to see, in past ive only seen them fail completely giving a very different reading so obvious they are faulty not like this one!, as the dashboard temp gauge doesnt go above normal/mid point until your over 100c its not obvious that its an issue other than fan coming on i guess, oh well you live and learn and hopefully that is coolant system sorted for now.

Time for a beer i think

[househead]

Time for a beer i think

I think I speak for us all when I say ... you've earned it!

[mr2garageswindon]

Result!

[thetyrant]

Result!

Yes hopefully all sorted will see what its like once weather warms up as was very cold last night duting test drive, doubt it was that causing the drop in coolant temp by 10degrees though!  thank you for reminding me about sensor as well as while it was on my list of possibles i had gone off on tangent looking at other things, mainly due to sensor seemingly working consistently....but wrong it seems!

[mr2garageswindon]

Its very easy to miss the simple stuff with diagnosis jobs been there many times myself.
Happy days its made a difference.
Now stop lookin for problems and drive the damn thing!