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MG Midget and Sprite Technical - Temp in winter?

hi everyone,

after tonnes of work on my car over the last 4-5 months, finally got her back and been driving around in the South of the UK today.

noticed that the temperature gauge is barely above the first start mark on the gauge. Normally sits around quarter... seems to be running all ok (rather well actually) and the thermostat was replaced within the last 12 months.

is this quite normal or something i need to worry about?
bk dyson

what model or year of car?

to save you having to put this and having to be asked everytime you could, if you wanted add your Vehicle Profile to be viewed

and, if you want adding a photo of it often helps

also on Customise you could alter your Username to include your first name (Bryan?)

ETA: just seen you have a 1500 from your other post but my comments still stand

I'll post a reply in another post as I'll get timed out on this one
Nigel Atkins

It may be that the thermostat is not closing properly, allowing coolant to circulate through the rad before the engine has warmed properly. You can test this by starting the car from cold and grasping the top hose between thermostat and radiator. It should remain cold for several minutes as the engine warms, and you should then feel the temperature of the hose increase quite suddenly as the thermostat opens. If the hose warms slowly and steadily from soon after starting it probably indicates that it is not starting off from a fully closed condition, and is faulty. Its an easy and cheap replacement job.

The second point to consider is that the ambient temperature may just be too cold to allow it to warm up fully, despite everything being OK with the car. It was common practice at one time to blank off part of the radiator on older vehicles in winter to stop the radiator from over cooling.

I change the thermostat on my car twice a year, using the standard 82deg C one in summer and replacing with the warmer running 88 deg C (or is it 92 deg C, I cannot remember and its in the car now so difficult to check!) in winter. I do the switch when I refill the antifreeze in the autumn. That said it probably won't be doing your engine any significant amount of damage if your mileage is low and you don't thrash the engine when it is running at the cool end of the range. You could try blanking part of the rad with a bit of cardboard to see the effect, if you like experimenting.
Guy

I don't know how much removing the rubber bumper and supports has helped your airflow but they may contribute

again a photo might help

if you have an oil cooler fitted then bear in mind your oil as well as 'water' is getting cooled (unless it has an oil thermostat fitted which isn't normally done)

I'm not a fan of oil coolers in this country on road cars

having said that my 1275 is about the same as your reading in winter

back in the day you could buy radiator grille cover/blinds on which you could open (or keep closed flaps)

I keep meaning to make a home made version with some plastic corrigated card across the middle of the grille and experiment with the width but I can't find any plastic corrigated card at the moment (a rally plaque or two would do though)

also bear in mind you might have apetures where your bumper was/is ?

ETA: typing whilst Guy was posting - 88C (190F)
Nigel Atkins

personally I'd keep antifreeze in all year round as it's a coolant and it help to maintain your coolant system

changing thermostat twice a year seem a lot of effort and very old fashion Guy :)

it's bad enogh keeping the system 'watertight' without 2 new gaskets being fitted each year

O/T
Guy,

having an open mind I tried your 'not havng a Driver's Handbook but discovering for yourself' method of folding the hood

unless I misunderstood, but I could see no other way, I tucked the sides inside the main part of the hood and it left the inside of the lift-a-dots against the rear plastic window which I didn't like

unless I done it wrong - no diagram and instructions in a book to follow so I might have gone astray :)
Nigel Atkins

Nigel,
Swapping the thermostats isn't a big job at all - I even tend to re-use the cork gaskets a couple of times at least. And I think it is better for the car to operate with the lower temp -opening valve in summer. I don't drain the antifreeze out in summer either. It only drops the level in the system by a couple of inches when switching the thermostats so fairly minimal dilution. Its a good time to check the whole system before the summer anyway. But I do check the concentration at the Autumn top up , or more often drain, flush and refill when I replace with the winter thermostat.

Fair comment about the hood fold. But equally (and unlike the approved method) the quarter lights don't rub on the hood frame. Six and two-threes I think!
Guy

Guy,
yes I think were on six of one and a half dozen of another, hopefully the rear quarter light don't rub too much on the frame as the cover holds it tight but I take your point

and quarter lights is a good description I've never thought of!

back on topic
full marks for >>check the concentration at the Autumn top up, or more often drain, flush and refill when I replace with the winter thermostat.<<

I'm afraid I've used so much 4-LIFE in this car let alone all the others to willingly cause further loss, and every time I refill or have to top means shortly after something will go wrong necessitating a full drain and refill and as I don’t have a rad drain plug it gets contaminated with muck and Waxoyl as it empties

I must admit I used a pair of my old stocking to filter and reuse it as I didn’t have enough spare fresh to use
Nigel Atkins

bk,I have found that my 1500 runs cooler without the rubber bumpers when moving but still heats up in traffic when stationary with the bonnet shut.

I changed my radiator recently, and thermostat and hoses, and the gauge reads something like what yours does.
If it is running well and not leaking coolant I expect it is fine.If it is taking ages to warm up though the themostat could be stuck open as said earlier.
JB Anderson

My 1275 overcooled in cool weather even without a mechanical fan. So like Guy I have summer and winter thermostats which help the engine run a bit warmer in the winter and a cooler in the summer. I think too they're 82 and 88 F.
Don't know if yours still has the standard fan; if so you may wish to think about removing it and repalcing with a thermostatically controlled electric one? That's what mine has together with an oil cooler, again thermostatically controlled.

On Guy's point about blanking the rad, my first car had an optional extra of a radiator blind controlled by a chain in the passenger compartment. Basically when starting in cold weather you pulled the chain which pulled the blind up the front of the rad and then as it warmed up you gradually released the chain and lowered the blind - a very simlpe affair but I did forget once to lower the blind as the engine temp rose and was rewarded by an overheating engine - no warning lights then...

Jeremy
Jeremy 3

Hi JB,

All my hoses and the rad where replaced last year as well. Cant tell if it takes ages to warm up as doesn't go past the first line!

Sounds like we have the same temperature. Have u driven yours lately?
bk dyson

Did you try feeling for the temp change in the top hose?
It needs to be done from a cold engine will start, but will show if the thermostat is stuck open
Guy

No Bk, I haven't been out in the midget since October but since the rad change about 2years ago it has run very cool while on the move but as said before begins to get hot when not moving especially with the bonnet shut.So blanking the rad would be a no go for me.
I prefer the engine to run cooler rather than hotter anyway.Not so good for efficiency, but less thermal stress.
JB Anderson

JB,
the blanking is of the radiator grille and not blanking it fully, vinyl radiator blanking 'blinds' were made and sold for this very purpose back in the day

some old cars and current cars have apertures that close off

if you consider that the aperture is sized for normal summer cooling air flow, and possibly for hotter climes than here, so can be reduced for winter use

at slower speeds and standstill the fan assists airflow which is where an engine driven fan is at a disadvantage because when you need the airflow the most it's going at its slowest and when you don't need it at all at start up from cold the engine fan is working especially working against what you want in winter

same with an oil cooler unless it has a thermostat fitted the cold thick oil is being cooled making the engine work harder and keeping it cold longer

if you're concerned about using a blind you could try just putting something in front of the oil cooler and see what difference that makes
Nigel Atkins

Nigel, I am very familiar with radiator blinds having fitted them to various kit cars I made about 30 years ago which had, for simplicity, radiators that were larger than required with a more direct air flow than they were originally designed for.
The blinds I used were contolled using a cable and pulley system from the drivers position, but in reality were just kept in one place once the optimum position was found.
In the Midget situation certainly in Winter a blind could be an idea if traffic hold-ups can be avoided but with the 1500 engine when stationary unless you have vents at the rear of the wings the throughput of air is marginal and I wouldn't risk blanking the rad. off. Thought about it once as a project but when I saw how quickly the temperature gauge began to rise when not moving even without blanking the rad. I decided to give it a miss.
JB Anderson

sorry JB I thought you missed my drift

I've seen a Volvo Amazon with a pulley system radiator blind so know what you mean

I've had no experience with 1500s but my 1275 runs very cold and soon warms up when statonary in traffic but this electric and the previous engine driven fan only allowed the needle up to the N

I did also put 'if you're concerned about using a blind you could try just putting something in front of the oil cooler and see what difference that makes'

and having a chrome conversion could have allowed more apetures at the front for cooling as there are so many variations that's why I suggested photos

Nigel Atkins

This thread was discussed between 28/01/2012 and 29/01/2012

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