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Cooling Tips


Best Answer Moke Spider , 03 July 2019 - 11:47 AM

The fitted temp gauges are notorious for being inaccurate. It would be wise to check the running temp with a known gauge before getting too far ahead of yourself.

 

As the other guys has said, the cooling jacket has to be clean and rust free. The engine Tune too must be good as well as this is also a common cause of hot running.

 

Where I am (In Australia) the temps in my area, go from -2 (like now!) to +45, though on many trips I do, the Temps are higher.

 

In many of my cars I run with a stock water pump, have the by-pass blocked off, an 82 deg thermostat, 6 Blade fan and the proper 4 tube type copper radiators.

 

The Stock Pump with a cast impeller are fine, though I am trialing one of the new 'plastic' impeller types.

 

It's imperative that the By-pass be blocked off. They bring on cavitation at lower speeds and only circulate hot coolant through the engine block, by-passing the radiator. This happens all the time when the engine is running, not just when the Thermostat is closed.

 

I really don't see any point in fitting a Thermostat 'cooler' than an 82 degree type. The 'cooler' thermostats don't allow the engine to be tuned properly and while it may runner cooler on some parts of a run, it will also runner at more normal temperatures too, ie, they can't give Temperature stability, which, in my view is more important than cool running.

 

The 6 Blade fans I find push the most Air through the Radiators. Some people find them noisy but I find them about the same or quieter than the plastic fans.

 

A decent 4 tube (or 4 core) radiator is better than any other. The common 4 tube and the 2 tube types have similar performance and also suffer the same issue. When you look at how the tubes are arranged in these, they are in a 'line' so those past the first don't get full air flow over them. The 4 tube radiators that were factory fitted to some models here (and the decent replacements) have off-set tubes so all tubes have air flow.

 

I've drive one of my cars in (uncomfortable) temps up to 53 degrees C and the engine only got up to 92 degrees. I find that with Air Temps up to about 45-ish, the engine temp hovers around the 85 mark.

 

In regards to coolant, I do run a Glycol based type in about a 30 / 70 ratio, however, plain water is superior only that it encourages rusting of the block. You can also get a straight inhibitor to mix with water, so you have that benefit but stops the block for rusting.

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#1 Echan42

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Posted 03 July 2019 - 08:40 AM

The warm heat of mallorca is getting the best of my mini I'm afraid, the old owner neglected the coolant in the system and it's a little gunked up, I already gave it some acid treatment and changed to 10% antifreeze and cooling is much better, but I'm still waiting on my thermostat gasket so I can take it in to the radiator shop for a proper de-gunking.

 

Anyway, long story short I'm trying to optimize my cooling for the warm summer ahead of us, I'm currently considering the following:

 

  • High capacity water pump
  • New Radiator
  • Electric fan
  • 72ªc thermostat

What radiator is best for road aplication, I've read that 2 core are better than 4 core since so many blades and cores stuffed into so little space just didn't have enough dissipation, are fletcher ratiators good? What radiator would you recommend.

 

I've fitted a 8 inch sucker turbine under the wheel well to help with hot air extraction from the ratiator, it's wired to an arduino that detects speed using GPS and when the speed is under 5Km/h it activates the turbine, I'm not really sure the difference was measurable since temps seem the same with or without.

 

I'm contemplating adding a intake fan on the front grille and removing my current install, or should I remove the mechanical fan and add a thermostatically controlled electro fan as my only cooling source? seems like most heating issues arise when minis are simply sitting in traffic, I've also heard of people altering the fan bearing diameter to make it spin faster, or changing from a 8 blade plastic fan to a metal 6 blade, there's so many options I don't know where to start.

 

Any insight or recomendations are highly apreciated!



#2 Ethel

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Posted 03 July 2019 - 09:02 AM

How do you know it's too hot, are you just going off the gauge or is it losing water, running on etc?



#3 nicklouse

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Posted 03 July 2019 - 09:10 AM

The single most important thing is to have a clean system.

Then an correct temp reading. Which is what?

#4 unburntfuelinthemorning

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Posted 03 July 2019 - 09:43 AM

First as above make sure the system is clear of rust build up.  Some people on here recommend a product called CLR to clean the system out.

 

I believe you need a minimum of 30% antifreeze to inhibit rust.

 

Make sure the hoses are in good condition.

 

Make sure the radiator cap is in good condition, is of the correct type and has the correct poundage.

 

A 74oC thermostat is probably a good idea for where you live.

 

An accurate water temperature gauge is a good idea if you don't have one.  Fit one of these first and you may not have to do anything else if the temperature's ok.

 

Go for an uprated radiator before you worry about the fan.  The Minispares 2-core is a good one.

 

Keep a mechanical fan - don't run without one.  The six blade metal fan moves more air but is less efficient than the plastic fan.

 

You can use a smaller diameter water pump pulley to speed the fan and water pump up.

 

If an uprated radiator doesn't keep the temperatures down in traffic then use a suck through electric fan to pull air into the wheel arch.



#5 Dusky

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Posted 03 July 2019 - 10:40 AM

So how hot does it actualy get?
Not much you can do after replacing all those items. Not much that should be done either, that cooling system should cope with regular 40°C temps.
Another thing to check is the engine tuning, fuelling and ignition can heavily affect the engine temps.

#6 Echan42

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Posted 03 July 2019 - 10:49 AM

How do you know it's too hot, are you just going off the gauge or is it losing water, running on etc?

I'm going off the factory smiths gauge, as far as I can tell it's never been tampered or substituted, it get's close to the H mark under specific driving conditions, mostly when exiting a highway and returning to lower speeds.

 

The single most important thing is to have a clean system.

Then an correct temp reading. Which is what?

I cleaned my system with the best product I could find twice, I'm waiting for my thermostat gasket in the mail so I can take it in to be machine cleaned and flushed.

 

First as above make sure the system is clear of rust build up.  Some people on here recommend a product called CLR to clean the system out.

 

I believe you need a minimum of 30% antifreeze to inhibit rust.

 

Make sure the hoses are in good condition.

 

Make sure the radiator cap is in good condition, is of the correct type and has the correct poundage.

 

A 74oC thermostat is probably a good idea for where you live.

 

An accurate water temperature gauge is a good idea if you don't have one.  Fit one of these first and you may not have to do anything else if the temperature's ok.

 

Go for an uprated radiator before you worry about the fan.  The Minispares 2-core is a good one.

 

Keep a mechanical fan - don't run without one.  The six blade metal fan moves more air but is less efficient than the plastic fan.

 

You can use a smaller diameter water pump pulley to speed the fan and water pump up.

 

If an uprated radiator doesn't keep the temperatures down in traffic then use a suck through electric fan to pull air into the wheel arch.

I'll keep my eyes open for CLR but I don't know if they distribute it where I live.

Is the stock temp gauge not known to be accurate? What gauges/sensors are known to give accurate readouts?

An up-rated radiator is n1 on my list, especially since the one installed had dirty water running thru it, mini-spares 2 core is definetly a good choice but I found a local vendor that sells these

http://www.bmcspares...ducts/FM-AR07-2

I've also seen mini youtubers fit these but I don't know if they're as good as they look becuase I can't find any reputable review.

I'll definetly look in to fans, my suck through electric fan doesn't seem to change much but I'm sure the hot air it expells actually makes a difference!

Thanks your post was VERY informative!



#7 Moke Spider

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Posted 03 July 2019 - 11:47 AM   Best Answer

The fitted temp gauges are notorious for being inaccurate. It would be wise to check the running temp with a known gauge before getting too far ahead of yourself.

 

As the other guys has said, the cooling jacket has to be clean and rust free. The engine Tune too must be good as well as this is also a common cause of hot running.

 

Where I am (In Australia) the temps in my area, go from -2 (like now!) to +45, though on many trips I do, the Temps are higher.

 

In many of my cars I run with a stock water pump, have the by-pass blocked off, an 82 deg thermostat, 6 Blade fan and the proper 4 tube type copper radiators.

 

The Stock Pump with a cast impeller are fine, though I am trialing one of the new 'plastic' impeller types.

 

It's imperative that the By-pass be blocked off. They bring on cavitation at lower speeds and only circulate hot coolant through the engine block, by-passing the radiator. This happens all the time when the engine is running, not just when the Thermostat is closed.

 

I really don't see any point in fitting a Thermostat 'cooler' than an 82 degree type. The 'cooler' thermostats don't allow the engine to be tuned properly and while it may runner cooler on some parts of a run, it will also runner at more normal temperatures too, ie, they can't give Temperature stability, which, in my view is more important than cool running.

 

The 6 Blade fans I find push the most Air through the Radiators. Some people find them noisy but I find them about the same or quieter than the plastic fans.

 

A decent 4 tube (or 4 core) radiator is better than any other. The common 4 tube and the 2 tube types have similar performance and also suffer the same issue. When you look at how the tubes are arranged in these, they are in a 'line' so those past the first don't get full air flow over them. The 4 tube radiators that were factory fitted to some models here (and the decent replacements) have off-set tubes so all tubes have air flow.

 

I've drive one of my cars in (uncomfortable) temps up to 53 degrees C and the engine only got up to 92 degrees. I find that with Air Temps up to about 45-ish, the engine temp hovers around the 85 mark.

 

In regards to coolant, I do run a Glycol based type in about a 30 / 70 ratio, however, plain water is superior only that it encourages rusting of the block. You can also get a straight inhibitor to mix with water, so you have that benefit but stops the block for rusting.



#8 unburntfuelinthemorning

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Posted 03 July 2019 - 12:45 PM

I forgot to include expansion tanks.  I've had two vehicles which liked to gradually blow water out of the radiator until the level dropped and they overheated.  One was a Mini, one a Land Rover.  Fitting an expansion tank solved this problem completely in both cases. 



#9 Boycie

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Posted 03 July 2019 - 04:21 PM

This may seem like a strange question, but does your fuel gauge read correctly...?
If it's giving artificially high readings your voltage stabiliser has failed which makes both gauges read high. When mine gave up, the temp gauge always ran between the 'N' and 'H' marks, staying mostly just under the 'H'.

#10 Rorf

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Posted 03 July 2019 - 05:20 PM

When steam is pouring out of the bonnet then it is overheating :lol:  Cast iron heads and blocks can take a lot of over heating abuse. Your best test is to use an IR (infra red) temp gun on the thermostat hosing and radiator hoses



#11 Ethel

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Posted 04 July 2019 - 08:18 AM

Lots of good sense above:

 

Overheating isn't a high temperature, it's only an issue if it causes other effects, pre-ignition or knocking being the worst. The system is likely to boil over before that.  Note Unburnt's comment, especially if you are having to top up coolant levels frequently - blown radiator caps allow localised boiling that ruins water circulation and escalates the problem rapidly.

 

Water jacket corrosion isn't good, but it'll stop heat getting in to water and keep the gauge temperature lower, unless it also creates sludge  that clogs the radiator. It's not your primary worry if the gauge is getting high unless you are still flushing out sludge.

 

Sounds like you have a problem dumping excess heat at reduced speeds. If it can keep cooler temperatures consistently at higher speed, then swapping to a smaller fan pulley will mean the fan and pump speeds are still faster when the road speed is lower. Though I think a more efficient radiator would be better first as it'll improve cooling at all speeds and won't take any more power - which would make more heat as well. At the most basic, a better radiator is one that contains more water.



#12 Echan42

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Posted 04 July 2019 - 12:35 PM

The fitted temp gauges are notorious for being inaccurate. It would be wise to check the running temp with a known gauge before getting too far ahead of yourself.

Oh wow, I had absolutely no idea but it sounds so logaical once you think about it, they're electrically driven 50 year old gauges, so I just ordered a laster thermometer will update as soon as it comes this weekend.

 


Where I am (In Australia) the temps in my area, go from -2 (like now!) to +45, though on many trips I do, the Temps are higher.

 

In many of my cars I run with a stock water pump, have the by-pass blocked off, an 82 deg thermostat, 6 Blade fan and the proper 4 tube type copper radiators.

It's so good to be able to assess my mini's cooling knowing of your experience I'm sure you've saved me a bunch of time and mistakes just by explaining and shining light on this.

I'm going to look into blocking off the by-pass even though I'm not a fan of altering and especially deleting factory intended designs, but if they blocked it off on later models I assume it's a good idea.

Since the radiator is going to be so important, can you tell me what radiators you've had good experiences with? Any 4 core I find in Spain don't specify if the tubes are off-set to allow proper airflow and I can't notice any difference in the photos they provide.

Hopefully I'll work my way towards a stable tempereture running mini! Thank you!

 

I forgot to include expansion tanks.  I've had two vehicles which liked to gradually blow water out of the radiator until the level dropped and they overheated.  One was a Mini, one a Land Rover.  Fitting an expansion tank solved this problem completely in both cases. 

Luckyly my mini isn't blowing water but I'll keep an eye out for any, I'm currently running a 1,2 bar ratdiator top wich is 17 psi, I coudn't find a 15 psi locally so I oredered one in the mail.

 

This may seem like a strange question, but does your fuel gauge read correctly...?
If it's giving artificially high readings your voltage stabiliser has failed which makes both gauges read high. When mine gave up, the temp gauge always ran between the 'N' and 'H' marks, staying mostly just under the 'H'.

Actually mu fuel gauge reads good but isn't always precise, I thought it was from inclines and g-force but you might be on to something, where can I plug my multimeter so see if the voltage stabilizer is working correctly? If the voltage rises over long journeys this would give me the impression the car was getting hotter.

 

When steam is pouring out of the bonnet then it is overheating :lol:  Cast iron heads and blocks can take a lot of over heating abuse. Your best test is to use an IR (infra red) temp gun on the thermostat hosing and radiator hoses

Yeah, I made sure not to use the word overheat I'm aware of this I just want to keep the temperature in check and at a temperature I'm confortable driving in 40c+ days for long trips.

Thanks for the insignt I ordered a temp gun off amazon!

 

Lots of good sense above:

 

Overheating isn't a high temperature, it's only an issue if it causes other effects, pre-ignition or knocking being the worst. The system is likely to boil over before that.  Note Unburnt's comment, especially if you are having to top up coolant levels frequently - blown radiator caps allow localised boiling that ruins water circulation and escalates the problem rapidly.

 

Water jacket corrosion isn't good, but it'll stop heat getting in to water and keep the gauge temperature lower, unless it also creates sludge  that clogs the radiator. It's not your primary worry if the gauge is getting high unless you are still flushing out sludge.

 

Sounds like you have a problem dumping excess heat at reduced speeds. If it can keep cooler temperatures consistently at higher speed, then swapping to a smaller fan pulley will mean the fan and pump speeds are still faster when the road speed is lower. Though I think a more efficient radiator would be better first as it'll improve cooling at all speeds and won't take any more power - which would make more heat as well. At the most basic, a better radiator is one that contains more water.

This post is filled with wisdom!

As I mentioned above I took care to not use the term overheat, I changed my radiator cap to a 17 bar wich is as close to 15 as my local shops could find. the old cap was unreadable.

Water jacket corrosion is slightly present under my thermostat and I can only imagine in other places too, that's why I'm waiting on my gasket to take it to a radiator shop to get it power flushed.

Can you recommend a radiator? Fletcher's 2 core are locally available and at a good price, but I can't find any reviews or feedback on these. Copper 2 or 4 core (with offset pipes) are generally the best to look for by what I understand from this thread.



#13 Magneto

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Posted 04 July 2019 - 02:05 PM

It's not mentioned in this thread, so I'll pipe in....my car was doing pretty much exactly as you described - I bought an inexpensive 2 core aluminum radiator off Ebay from one of the chinese suppliers - instant cure to my issue. Most recently I was running some very steep and very long mountain passes in 90* F temps (well at the lower elevations at least - when we got over 12,000 feet it WAS cooler!) and my temps never went above N, where it used to climb steadily to just under the H. In stop and go traffic in temps as high a 102* it never climbs above the N now. I did install a new water pump but my system was clean and did not require flushing.

 

My previous Mini ran hot on the highway and cooled off in stop-go driving, a smaller water pump pulley cured that one - but - I had chaged the final drive from 3:44 to 2:76 and figured since the engine was turning so much slower on the highway than it used to that's why it heated up over a long run. Smaller pulley cured it.



#14 Wiggy

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Posted 04 July 2019 - 02:48 PM

If your radiator is indeed full of rust/sludge/crud, then your heater matrix will be too.



#15 Echan42

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Posted 06 July 2019 - 07:01 PM

Deleted my post to avoid confusion and will provide temps with motor running and not right after killing the ignition.

Thanks.


Edited by Echan42, 06 July 2019 - 08:07 PM.





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