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MG Midget and Sprite Technical - Dual oil/water gauge

Hello All.

I did a little refreshing / flushing of the cooling system early September & at the same time changed the thermostat. Purchased from a supplier in Swavesey. Standard 82 C.

All fine with temp back as per norm just over the N on C-N-H dial. I say fine as it always has parked just above C when stone cold.

Later in the month I decided to change the gauge itself as the oil pressure has always had a similar problem - never returns to 0 lbs.

Purchased 'brand new' gauge from supplier in Wisbech. Oil pressure part is fine but even when engine fully warmed up the dial only reaches half way from C to N.

Spoke to Wisbech this AM and been told could be the thermostat! Regardless they have agreed to take back & test. But I'd be interested to know whether the 3 thermostat options available make a difference to where the needle sits at normal operating temp as inferred. Can't help wondering there is a 'curved ball' here somewhere.

Just a thought - I'm using just tap water in the system at mo. When I'm confident all Ok I planned to put back rainwater & antifreeze 50/50. Would this have any affect?

I'd welcome any comments.

Gavin.
Gavin Rowlesx

Hi Gavin,

I wouldn't worry. I run an 88degree thermostat and the normal running position for the temp gauge is about two needle widths below "N". Only creeps up in extreme circumstances e.g. stationary with no natural airflow through radiator on a very hot day.
Ray Rowsell

Gavin - I'm running a K with an emerald ecu.

The smiths gauge reads low all the time, but as the ECU switches the fan on from a separate sensor, I know that it's running at the correct temp as the fan cuts in and out properly.

I think the standard gauges can be so unpredictable that they're better used as an indicator of what is normal, and not to be relied upon for any confirmation as to an actual temp. If that makes sense.

Good buy would be an infared temp sensor gun rather than a new gauge - about the same price. You can point it at different parts of the engine and see what temp things are, and then note what 'normal' is on your gauge. Then just use it as an alarm for when things depart from normal.
L McInally

Make sure you test your stats on the stove with the wifes favorit pot before installing them

Then you will know if the temp for opening is correct or not

Prop
Prop and the Blackhole Midget


I don't think it is the stat Prop - I mentioned that when replaced early Sept my old gauge behaved just as with the old stat.

Nice tip about the wife's pots though. Ta.
Gavin Rowlesx

Before you remove the gauge again you could try carefully removing the sensor 'bulb' from the head and immersing it in boiling water. In theory at 100 degrees C, the needle should rise to a point between the little calibration dots midway between 'N' and 'H' as seen in this photo.
http://i.ebayimg.com/00/s/MTYwMFgxNjAw/z/qpsAAOSwq7JUAhUK/$_57.JPG

Jim
J Smith

Gavin sounds like you are running too cool. Pop over to Lawrence and pick up some of his muck, put it in your block and it will run hotter :-p
David Smith

Gavin,
I assume you checked the stat opened and closed before fitting to the car

with an 82c stat fitted, car at full operating temperature, going along on an open road my gauge 9bothe present and previous) would be about half way between end of white C range and the N

it ran like well that for 6 years with no problems

taking on Ray's idea and Guy say the engine needs to be warm I'm currently experimenting with an 88c stat fitted, I missed the really hot weather in July to test it but I don't fully feel comfortable with it but might as well leave it in over winter and try it at next year's heatwave
Nigel Atkins

Rainwater? With the bonnet up and the rad cap off it's going to take a long time to fill, even with our weather.
Graeme W

"Rainwater" ... of course there is always the AC run off water

Good one david... LOL.

Jim ... I like your idea... that would tell you what the gauge is basically calibrated at...but the imagery of running thur the house with a pot of boiled water to test the guage has a good story to tell

Prop

Prop and the Blackhole Midget


Jim - will try your test thanks.


Nigel.
I did not test the new stat but as mentioned earlier my old gauge performed just as it had done prior to fitment of new stat. So am quite happy that engine is reaching correct running temp. Maybe the old stat was not 82C? Your description of your current situation mirrors the results I am now getting. Surely a standard 82C stat should provide Normal (N) temp on a properly calibrated gauge?

Graeme - rained here heavy for about 10 mins this week so have plenty in my water butt. Let me know if you want a bottle - special MASKkent rates apply.

Thanks everyone else.


Gavin.



Gavin Rowlesx

Not enough crap out of mine to make it overheat David. But I'm assured not removing it all, will screw up the engine. ;).
Lawrence Slater

>>Surely a standard 82C stat should provide Normal (N) temp on a properly calibrated gauge?<<

Gavin,
you'd have thought so - but then you'd remember its a British built car from decades ago and they were fiddling around with it to make it more acceptable to it's main selling markets and that's not the UK

quite honestly I never worried about it until a seed of doubt was sown but before that the car went very well and had much more margin from getting too warm/hot/overheating

it's because I got so used to seeing the needle well before the N that I'm not comfortable with where the 88c stat has the needle

even with the 88c stat I find my engine soon cools down when parked up and left for a while

I think you might be worrying unnecessarily about where the needle is on the gauge, I'd be more concerned with cleaning and flushing out the tap water and refilling with antifreeze/coolant

here's a photo of the other gauges with numbers on that might add to your confusion and concern -

Nigel Atkins

Nigel wrote

"you'd have thought so - but then you'd remember its a British built car from decades ago and they were fiddling around with it to make it more acceptable to it's main selling markets and that's not the UK"

I agree.

In my experience BMC cars were overcooled for UK use. In the 1960s I ran a Farina A40 Countryman for several years with the fan blades removed. Everyday use which included commuting to work through the town and my attempt to emulate rally drivers through the lanes!! Clearly, traffic conditions were nothing like they are now but, only once do I remember having to get out of the traffic as the gauge was heading towards "hot". I used many "A" and "B" series engined cars and it annoyed me that they never read "N" in normal running. I suspect that "N" was calibrated for hotter markets.
Ray Rowsell


Thanks these further comments.

Will drain and replace 50/50 & run with it for a while.

Gavin.



Gavin Rowlesx

I suspect you are correct Ray. Mine has had an 88 in from earlier in the year all the way through the hot weather and has just about read N or just under all the way through.

Nigel gave me his 88 to warm mine up enough to get warm in the cold weather as suggested by Guy. Its been really great Nigel and never overheated even in less than walking pace stop start traffic for over 1/2 an hour. (The clutch packed up instead :-( ). And I kept forgetting to put the cool one back for the summer and all is still well.

Dave
Dave Squire

Gavin,
unless East Sussex gets particularly frozen and/or your car is kept outside or in a cold garage I don't think you need to go to 50% anti-freeze

at 33% the solution "Commences to freeze" at "-19c" and "Frozen solid" at "-36c"

for 50% it's "Commences to freeze" at "-36c" and "Frozen solid" at "-48c"

figures are from the Driver's Handbook which I just happen to have a copy of, marvellous book I wonder if you can still get copies?
Nigel Atkins

Dave,
I think your memory has gone a bit 'Nigel' but just for once mine is good (well on this)

I sent you a spare working 82c stat as at the time you had a 74c stat fitted hence the lower temp on your car, some suppliers don't even specify a 74c for 1500s, normally in this country they have 82c stats fitted with 88c for 'cold climates'

you then found even the 82c stat I sent didn't give you what you wanted so you sent off for and fitted an 88c

so I can't take the credit for your happiness (unless you're getting a round in when mine will be a pint of the finest (real) ale)
Nigel Atkins

Nigel - garage & doubt would get below minus 5.

25% I think. Ta.
Gavin Rowlesx

Gavin,
allowing for wind chill factor at first running the car especially if you have an engine driven fan cooling a very cold engine, I'd be at least 33% antifreeze/coolant

that's of course if you've got the car in a garage that gets very cold or actually ...

dare I say it ...

... use the car during the coldest part of SORN season

"mummy the nasty man has used rude words again"
Nigel Atkins

This thread was discussed between 25/09/2014 and 26/09/2014

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