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Post by nilejackson on Nov 1, 2009 0:42:07 GMT
So, had a good 150 mile run in my beauty two days ago, she seemed great especially with the long distance, I noticed from time to time the tempreture would fluctuate quite alot.
It would normally stay around the half way mark and at points would be below the red line mark. This tended to happen when becoming stationary in traffic.
I dont think its a terribly massive problem as the engine didnt over heat.
Is this a common thing on older cars or is there something in particular that could cause the problem. Yes i did check the water.
Ideas?
Thank you
Nile
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Post by (minisniper) on Nov 1, 2009 0:47:55 GMT
Well from my experience, it is something that happens with older cars however I wouldn't dismiss it as not being something more serious. It might just need a good flushing but I'm sure someone will be along soon who can advise you better.
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Post by minimaniac on Nov 1, 2009 12:53:37 GMT
It could be the thermostat isn't working properly. The wax stats fitted to Minis fail in the closed position.
It could also be the radiator cap isn't sealing. Check that the cap has a rubber seal at the bottom and make sure there is some resistance (i.e you need to press it down) when you re-fit the cap.
Its also worthwhile flushing the whole system out as well to get rid of any crud that's built up over the years.
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Post by asahartz on Nov 1, 2009 12:55:23 GMT
There may be more fluctuation than on a modern car, but it's not really warm enough out right now to affect it much.
The cooling system is very basic, and obviously tends to work harder on an auto which relies on the oil for drive, hence heating the oil more. A thermosyphon effect draws cooler water from the bottom of the radiator, with the assistance of a pump, and pumps it around the engine block. The hotter water circulates to the top of the engine, where a wax thermostat restricts circulation until it reaches its operating temperature. It then opens to allow the water out to the top of the radiator. The radiator cap pressurises the system to allow it to run at over 100 degrees without boiling.
So there are only a few possible problems. 1) the themostat fails. Most often it fails in the closed position, so the car overheats rapidly. (Should it fail open, the car takes a long time to warm up) 2) the radiator cap leaks or fails to hold pressure, so the car overheats and loses water even at normal operating temperature. 3) the water pump fails to pump. This was common on pumps with plastic impellers which would break off or wear, but most are now metal, and these generally only fail by leaking or bearing failure which makes them noisy. 4) waterways in the engine or radiator become blocked with rust, silt or Radweld, so the engin does not cool effectively. Flushing with a hosepipe or pressure washer, preferably in the reverse direction to normal flow, should cure this. Radweld should be avoided unless in an absolute emergency!
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Pink-Shifty
Full Member
Tech Guru/Welder of the year 2009
Posts: 51
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Post by Pink-Shifty on Nov 1, 2009 13:12:38 GMT
I'd go with the Rad, the other thing to check is that the fan blade is on the right way round. This can give the symptoms you describe.
If you look at a fan blade, its a u shaped "cup", the cup part should be facing the rad.
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Post by jockduck on Nov 5, 2009 10:05:56 GMT
I live in Australia and I find that Mini automatics do run hot, once the ambient temp gets above 30 deg C the temperature guage climbs, I have changed radiators, thermostats and checked fans but no change. My belief is that the autobox soaks up a fair bit of power and converts it to heat.
Ian B
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Post by clambod on Nov 5, 2009 14:37:48 GMT
I'd go for a flush through. when refilling use the antifreeze coolant type. It may be worth checking the temperature sender.
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Post by kalkat on Nov 5, 2009 15:25:39 GMT
My car had cooling issues which were partly solved by flushing, the rest doesn't really apply here as I had to go for a different radiator 'cos my car is....... different (Cooperised) Yes, a flush would be a good place to start. Another thing to do at this time of year is give the whole cooling system a once over, ready to put anti-freeze in as it will 'seek' any cracks or perished hoses.
Emma
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Post by asahartz on Nov 5, 2009 18:06:12 GMT
I live in Australia and I find that Mini automatics do run hot, once the ambient temp gets above 30 deg C the temperature guage climbs, I have changed radiators, thermostats and checked fans but no change. My belief is that the autobox soaks up a fair bit of power and converts it to heat. Ian B I do agree; it has the benefit of making the heater quite toasty in my Elf! However right now in England the temperature is struggling to climb into double figures, so there's a problem - while he'll get away with it now, come the summer it will boil over if not sorted.
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Post by notamini on Nov 20, 2009 23:50:29 GMT
See if this helps you. It certainly made a big difference for me. Go to members.tripod.com/austin_america/id77.html and scroll down to Cooling System. There are three suggestions there that work wonders, especially the thermostat!!
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Post by niceboy1275 on Dec 1, 2009 10:16:29 GMT
Both my matics had this problem. Turns out that in both of them the water pump impellers were both rusted away and barely pushing water. If your going to the extent of reverse flushing the radiator I'd take it out, get it professionally cleaned (rod cleaning isn't it called?) and then change the water pump over at the same time. Theoretically, then you won't have to touch it again for at least 12 months other than a fill and quick flush. Just my 2cents worth :-)
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Post by Admin/Founder 2 on Dec 1, 2009 10:57:46 GMT
id agree with that Water Pumps are only £15 tops so id flush the coolant out till the water runs clear then replace all the cheap bits too that can cause problems Replace the Pump,thermostat,Rad hoses and jubilee clips to be on the safe side,new rad cap and refill with nice new fresh coolant mixed to the correct ratio or if you want to skip the mixing you can buy ready mixed these days You can get separate Anti Corrosion Additives for your coolant too but most good quality Coolants have anti corrosion mixed in these days Hope you sort it out Huggz Jodie
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