Running hot - any advice?

[Steve_Lindford]

You can get some feed back by feeling the flow and return pipes through the hole under the armrest. You should see the needle on temp gauge drop a little as the thermostat opens.

Also - is the spare wheel blocking the front grille??

Steve_Lindford

[4129R]

As for the sender, it's easy to see if one has failed completely because it will have virtually zero resistance & go directly to earth/full scale deflection on the gauge. One that's partially failed is harder to spot without checking the resistance vs temperature. There's also a chance you have the wrong sender for the gauge, I think they do come in different resistances ?

I think my temperature sender has failed. It has a far lower resistance that two others I have tested. 383 against 1180 on my meter.

The engine warms up super quickly and then goes to 130'C just as the water is passing through the radiator. New rad, new thermostat, completely flushed through coolant system with antifreeze, and no hissing when I undo the new 10 PSI pressure cap on the reservoir. New sender on order from SJ Sportscars.

[4129R]

New temperature sender fitted from SJSportscars.

Running very hot problem now cured. As suspected, the sender was giving a false reading, and the new sensor has the car running at 90'C, so no major dramas or expenditure.

At an air temperature of 10'C the resistance of the old sensor was 38.3 ohms, whereas the new sensor had a reading of around 117.0, which seems to tie up with the figures posted by Europa TC earlier in this thread. At 38.3 ohms, I reckon the temperature reading of the broken sensor would be about 125'C, which it was reading, hence my concern.

[BDA]

 

[Fotog]

I know from being in the industrial heating systems business (kiln building) that measuring temperature accurately can be quite difficult. Anything and everything from the sensor to the sensing circumstance (where, how, etc.) to the readout, and any electronics in between can and will affect your measurement.  The more measurements the merrier I think, as you start to get a consensus.  But in many many circumstances, there's no way to get additional measurements.

So just beware:  you can't trust anything by itself. And there is no reason that something that reads out digitally is any better than something that reads in an analog fashion.

[4129R]

I know from being in the industrial heating systems business (kiln building) that measuring temperature accurately can be quite difficult.

Measuring temperature (electrically) accurately............

Surely measuring anything with a mechanical sensor (mercury or the wax probe thingy with the long capillary tube surrounded with coiled wire) is more accurate, but less convenient.

I knew something was amiss as the gauge was recording 130'C but the expansion tank was cold, and the filler cap was not pressurised. At standard pressure, pure water boils at 100'C, if pressurised that can rise to say 120'C, but there was no pressure, it came up to temp far too quickly, and the top rad hose had only started getting hot = the thermostat had only just opened to allow free coolant circulation. I don't know how antifreeze affects the boiling point of water. I know it lowers the freezing point, that is its purpose, but I don't know how it affects the boiling point.

I worked out that the pump sucks water from the radiator, pressurising everything  north or upstream of the pump, so I knew it was not at 130'C, it just did not add up.

Anyway, the new sensor seems to be performing as expected.

[Fotog]

That's great that you've got it handled.

And you've got me thinking that I should try to do better.  My gauge reads as below (orange line) if the ambient temperature is below something like 85 degrees F, and I've come to accept that I don't really know what the temperature is, but it's under control.  It creeps a bit higher at higher ambient temperatures, but with the fan on it still doesn't peg at 130.  So I've been satisfied.  But you've got me thinking that I'd be glad to have a little more accuracy here.  Even if my gauge and sensor are pretty accurate though, I wonder what that temperature is that's showing on the gauge?  I don't know how to read that thing.  LOL!

[BDA]

I've attached a picture that gives an indication of how to read it. The hash marks are not halfway between 50 and 90 or 90 and 140 as I tend to think about them but it seems clear that your water temp is over 100°C which may not be terrible (I assume you're not boiling water out of your system) but when my car was new, the needle was always just before the 90° mark which is what I aim for (actually, my car runs closer to 75°C but I have a different engine).

[Fotog]

Thanks.  I think you posted that earlier in the thread.  It looks like it should be helpful, but given my 130 maximum, I'm still uncertain about what is supposedly my temperature. 

Some day I'll use a thermocouple which should be quite accurate and thread it in past a hose coupling and get a real idea of the temperature.  For now I think my temperature is "ok".

[BDA]

He he… I went back and saw where I posted that graphic before. That’s happened twice recently!

Based on my experience, I would say your car is running warmer than it should but unless you’re boiling over water, you are ok but you should be running cooler. I would try to find why it’s running so warm.

[EuropaTC]

I think it was generally accepted that the Stromberg cars ran hotter than Weber/Dellorto cars, it was mentioned lots of times in my Club Lotus days.

Miles Wilkins also makes a passing reference in his book on the TC, saying that they run 5C hotter than Weber engines, 95C being normal. He put that down to several things,  the leaner mixture, port shape and, in the Elans, the smaller radiators introduced at the same time. The radiators are the same on Europas so that reason is out, but even so I wouldn't be surprised to see them a touch warmer.

Brian

[4129R]

It seems that the water temperature sender in the thermostat housing is 1/8" NPT thread.