Overheating Issue

Post by **h20_mako** » Fri Jun 19, 2009 3:54 pm

I am encountering overheating issues on my minor.

Radiator
Would you suggest that i use coolant addictive in the radiator to lower the temp?

I have read other threads stating a 7lbs radiator cap is suitable for a original radiator. am i correct? as i am afraid the wrong cap will hold more pressure and thus temp increase.

I am on a original radiator, is it advisable that i can fit in a more modern radiator if size permits?

Fan Push or Pull??
(pic as attached below)(direction of blow shown in RED arrow)
I have fitted an air con system with an electric fan mounted between grill and radiator. The fan is on at all times as driving in my country requires lots of start/stop driving.

Standard engine fan is made of metal and belt and pulley driven by the engine, i am thinking of replacing it with an electric fan. Is it advisable?

Is the direction of blow for the 2 fans correct? as i have to make sure that i have optimum cooling.

Post by **bmcecosse** » Fri Jun 19, 2009 3:59 pm

I would Not change the fan to electric - for your purpose you need cooling almost all the time. I would either fit another pair of blades at right angles to the original pair - or a larger multiblade fan from a Spridget or Marina. The rad cap is just there to contain coolant - and to raise the boiling point of the water slightly. I would not advise specific coolant additive (such as 'waterwetter' ) - but a really good flush out should help - then in this country we would add antifreeze which contains inhibitors to prevent corrosion - there may be a similar product for you, just without the ant-freeze element ?

Post by **h20_mako** » Fri Jun 19, 2009 4:12 pm

sorry do you mean fitting a new fan with similar angle to the current fan?

raising the temperature of the radiator fluid is acceptable? wouldn't it affect the overheating issue i encounter?

Are the direction of blow for the 2 fans alright?

my radiator has suffered a burst previously and i have welded it back so i'm not sure if that is affecting the overheating issue. considering whether to get another original minor radiator or a modern replacement? any advice?

yeah my country temp is mostly 34degreesC throughout the year so its pretty warm here.

Post by **bmcecosse** » Fri Jun 19, 2009 7:14 pm

Yes - another pair of the identical blades - but set at right angles to make a X. Your fans look ok - but I have no doubt your problem is caused by the air-con you have added! Your fans are fine - but now you are blowing pre-heated air into the Minor rad - so it's no wonder it is overheating. You could take the thermostat out -and fit a lower value stat - or even what is called a 'blanking sleeve' - you must not run without a thermostat or blanking sleeve in place. Personally - i would throw away the air-con, and put the top down !

Post by **MarkyB** » Sat Jun 20, 2009 8:18 am

Weren't you saying something about the tickover speed in another post?
Although the Minor is overcooled in the UK it probably isn't in Singapore.
On top of that you are giving it more work to do driving the A/C compressor and electric fan, then blowing even hotter air over everything.
You will probably need the equivalent of a wind machine from a film set to make it work.
How big is the A/C radiator? Could you mount it somewhere else?
I think you will need an electric fan for the engine too, a big one ideally.

Post by **bmcecosse** » Sat Jun 20, 2009 9:34 am

Electric fans are only for occassional use - in traffic. This car needs a constant stream of air - fixed mechanical multi-blade fan is the way to go!

Post by **h20_mako** » Sat Jun 20, 2009 9:53 am

i think there is some misinterpretation regarding the aircon fan blowing warm air.

i will have to take some photos and post to be more precise and exact. So that i can acquire valuable knowledge from all.

will be posting pics soon..

Post by **bmcecosse** » Sat Jun 20, 2009 10:00 am

The air con fan is blowing air through the aircon heat excahnger - that air picks up heat - and is then blown through the normal Minor radiator! So the poor Minor rad is having to try to cool the engine - which is already working very hard driving the air con AND the car - with air that starts off at 34C - and then is heated up by the aircon rad! It's got no chance. Possibilities are to move the air-con rad away someplace else (or throw the air con away) - or increase the air flow through the two rads - best way in my humble opinion is to fit a larger multiblade mechaniacla fan - the Spridget or Marina fans will be ideal. Note that a Mini fan would be useless - it blows instead of sucking!

Post by **h20_mako** » Sat Jun 20, 2009 11:08 am

Pictures are in.

Electric Fan that switches on with the air con.

Post by **h20_mako** » Sat Jun 20, 2009 11:10 am

Aircon fan radiator/condenser is placed under the driver seat

aircon fan radiator/condenser

Post by **h20_mako** » Sat Jun 20, 2009 11:12 am

Engine fan
these blades are at 90degrees angle, with four blades. so you suggest a spridget or marina fan for more cooling?

is the fan a direct bolt on? any modifications needed if i use a spridget or marina fan

Post by **bmcecosse** » Sat Jun 20, 2009 12:39 pm

Ahh right - but how on earth does the air con heat exchanger work under the seat??????? You've created a closed loop - the sytem can't reject any heat!!!! It must make for a very warm backside! But at least it's not affecting the engine cooling. You already have the double blade fan forming a cross - good, and as long as the additional electric fan is pushing air into the rad, and the mechanical blades are sucking - that should be more than enough air flow. Yes a Spridget/Marina fan would be even better - but you should have enough flow already. Your problems must then be down to thermostat issues/blocked up radiator and/or block/ knackered water pump - it is possible the blades have corroded off - you would need to take it off for inspection - or of course, maybe the head gasket is leaking.

Post by **h20_mako** » Sat Jun 20, 2009 1:14 pm

haha its not really under e driver's seat. Its underneath e car positioned under e drivers seat.

I was informed by e mechanic that i will need to change e mechanical fan as e metal will degrade after time and thus less air will sucked reducing efficiency.

Will it be advisable to use a modern radiator if my radiator is clogged?

Post by **alex_holden** » Sat Jun 20, 2009 3:12 pm

h20_mako wrote:I was informed by e mechanic that i will need to change e mechanical fan as e metal will degrade after time and thus less air will sucked reducing efficiency.

That sounds like nonsense. Perhaps he meant the impeller in the water pump?

Will it be advisable to use a modern radiator if my radiator is clogged?

The standard one is already pretty good if the core isn't clogged up, but I believe special aluminium ones are available for even better cooling on high performance engines. See: http://mog.myfreeforum.org/about1030.html

Post by **alex_holden** » Sat Jun 20, 2009 3:14 pm

BTW wouldn't it make more sense to have the electric radiator fan controlled by a thermostat in the radiator water rather than only switching it on when the air conditioner pump is active?

Also, if I were you I'd be rather concerned about the condenser being punctured by stones thrown up from the road.

Post by **bmcecosse** » Sat Jun 20, 2009 4:26 pm

Yes -I see it's under the car - very vulnerable -and I still can't see how it rejects any heat - but that's not the worry here. Good flushing - maybe with some drain cleaner in the water I think! The cooling fans are fine - water pump impeller maybe knackered and change thermostat for a low setting - or a 'blanking sleeve' for ultimate coolking where you don't have to worry about a heater!
http://www.minisport.com/acatalog/info_11G176.html

linearaudio · Post by **linearaudio** » Sat Jun 20, 2009 6:13 pm

Why is the electric air con fan on the front of the radiator at all? Surely it should be placed to blow air through the air con radiator when the air con is switched on, not blowing through the engine cooling radiator? Other than the aircon pump adding a bit more load on the engine the aircon is surely a seperate circuit?

Post by **MarkyB** » Sat Jun 20, 2009 6:33 pm

Electric fans are only for occasional use - in traffic

They don't have to be, that's just the way modern cars are set up as it's efficient.

I think the heat exchanger has a fan on it already to make it work.

If the electric fan in front of the rad doesn't sort out the problem then I'd replace the rad first as it's had problems in the past and may have been compromised by the repairs.

What are the symptoms of the overheating?

It would probably be worth getting some heat shields made up for the carb and fuel pipe as petrol vaporisation can be an issue in traffic even in the UK.

Post by **Roni** » Sat Jun 20, 2009 11:47 pm

This might give you an idea of what is possible, if everything is working as it should, in cooling a Minor on a hot, mid 30's, day.
My setup; 1098 engine, 82 deg thermostat, anti-freeze/corrosion inhibitor, 7 lb cap, no engine fan, electric fan in front of radiator on a thermostat switch set at 90 deg.
When the air temp is up into the mid 30s the car will run at 90 - 95 deg running at 100 kph. The fan will be turning on and off. When traveling slower it is much the same but the fan is more active.
When it is cooler, 20 deg, it usually runs at around 85 deg, with the fan only ever coming on when sitting stationary.
Lately, I haven't heard the fan for a long time. It is probably more a case of over-cooling now that the air temps are in single digits.

Post by **Mogwai** » Sun Jun 21, 2009 12:24 am

I don't know what the availability would be in Singapore but you can get a double or triple row matrix which will fit the minor rad & improve cooling efficiency, a cooling system specialist should be able to recon your rad with one
(if that is the fault)