SERIOUS OVERHEATING

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Doug G
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SERIOUS OVERHEATING

Post by Doug G » Sun Jan 01, 2017 15:33

Overheating at 2 miles, coolant going into the o'flow tank, steam etc.

Related : when it gets overheated it would miss on one or more cylinders - see separate topic)

Mechanic recommends the radiator be flushed out. How do you do this?

My garden hose (before the pressure reducing valve) is about 140psi.

I could also stick it into the engine water intake to 'back wash' it as well.

There is no thermostat in the thermostat housing, I removed it, although I have a new one in my drawer.

Suggestions?
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Daniel
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Re: SERIOUS OVERHEATING

Post by Daniel » Sun Jan 01, 2017 19:08

Hi Doug,

come over to Germany. We currently have about -5 to -8°C. This cools down your engine very well! :roll:

My first thought was the thermostat, but when I read you have removed it already this is not the solution. Anyway driving without the thermostat is not good for the engine as the water flow gets to fast and the water cannot transport the heat to the radiator in an optimal way.

Have you or your mechanic checked the waterpump? Is the water circulating properly?

Regards,
Daniel
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Tim
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Re: SERIOUS OVERHEATING

Post by Tim » Wed Jan 04, 2017 2:21

Removing the thermostat can allegedly cause localised overheating. The story goes that taking it right out means that not enough water circulates to the far end of the block so they get hot at the expense of the front cylinders which stay nice and cool. You can get a sleeve that replaces the thermostat and slows down the circulation, or some people snip the centre out of the thermostat and just use the outer ring. I've never done it because the weather gets cold enough in winter here to need a thermostat and if your cooling system is actually working then the thermostat does its job.

Flushing the radiator is exactly what it sounds like, you undo all the hoses and jam a garden hose into each orifice alternately, trying to dislodge all of the rust, mud and silt that is blocking all of the tubes. There are a bunch of chemical additives you can get that are supposed to help dissolve and dislodge the sediment too. It will probably only help a small amount. The stuff tends to settle pretty well and is hard to get moving. Also its pretty well impossible to dislodge the buildup in the cooling jacket of the engine itself. If the cooling system hasn't been looked after, the engine can get a lot of muck built up in it.

Around here there are still some old fashioned radiator service places that can 'rod out' a radiator. As I understand it, they unsolder the top or bottom tank and poke a wire rod down each of the tubes in the core. Its meant to be pretty successful, but I suspect that if the radiator is that bad, its probably going to be starting to get a bit thin anyway and may be due for replacement.

I haven't had to replace a radiator for a few years so I don't know what the current choices for an uprated radiator are. In Australia we always used to specified a "Cooper S" radiator. I don't know what the part number was on these, but they were very good. I don't think they are available anymore. I think the radiator fitted to mine now is the 4 core competition one that Mini Spares sell. It seems to be pretty effective. A lot of people seem to be using the cheap alloy ones that are made in China and sold through Ebay. I have no personal experience, but they look OK and they are significantly cheaper. The people using them seem to think they are alright.

After that, a good quality water pump, keeping the coolant in good condition and making sure the engine is tuned correctly are all important. Tuning can make a lot of difference. An engine burning too lean will get hotter than one running richer.

Tim
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Doug G
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Re: SERIOUS OVERHEATING

Post by Doug G » Wed Jan 04, 2017 16:42

Daniel wrote:Hi Doug,

come over to Germany. We currently have about -5 to -8°C. This cools down your engine very well! :roll:

My first thought was the thermostat, but when I read you have removed it already this is not the solution. Anyway driving without the thermostat is not good for the engine as the water flow gets to fast and the water cannot transport the heat to the radiator in an optimal way.

Have you or your mechanic checked the waterpump? Is the water circulating properly?

Regards,
Daniel

I have a new replacement thermostat in my 'moke' drawer.

Will check the water pump. Thanks for that suggestion.
BTW I will decline the invite to Moke in Germany. :lol:
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Doug G
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Re: SERIOUS OVERHEATING

Post by Doug G » Wed Jan 04, 2017 16:44

Tim wrote:Removing the thermostat can allegedly cause localised overheating. The story goes that taking it right out means that not enough water circulates to the far end of the block so they get hot at the expense of the front cylinders which stay nice and cool. You can get a sleeve that replaces the thermostat and slows down the circulation, or some people snip the centre out of the thermostat and just use the outer ring. I've never done it because the weather gets cold enough in winter here to need a thermostat and if your cooling system is actually working then the thermostat does its job.

Flushing the radiator is exactly what it sounds like, you undo all the hoses and jam a garden hose into each orifice alternately, trying to dislodge all of the rust, mud and silt that is blocking all of the tubes. There are a bunch of chemical additives you can get that are supposed to help dissolve and dislodge the sediment too. It will probably only help a small amount. The stuff tends to settle pretty well and is hard to get moving. Also its pretty well impossible to dislodge the buildup in the cooling jacket of the engine itself. If the cooling system hasn't been looked after, the engine can get a lot of muck built up in it.

Around here there are still some old fashioned radiator service places that can 'rod out' a radiator. As I understand it, they unsolder the top or bottom tank and poke a wire rod down each of the tubes in the core. Its meant to be pretty successful, but I suspect that if the radiator is that bad, its probably going to be starting to get a bit thin anyway and may be due for replacement.

I haven't had to replace a radiator for a few years so I don't know what the current choices for an uprated radiator are. In Australia we always used to specified a "Cooper S" radiator. I don't know what the part number was on these, but they were very good. I don't think they are available anymore. I think the radiator fitted to mine now is the 4 core competition one that Mini Spares sell. It seems to be pretty effective. A lot of people seem to be using the cheap alloy ones that are made in China and sold through Ebay. I have no personal experience, but they look OK and they are significantly cheaper. The people using them seem to think they are alright.

After that, a good quality water pump, keeping the coolant in good condition and making sure the engine is tuned correctly are all important. Tuning can make a lot of difference. An engine burning too lean will get hotter than one running richer.

Tim
Will check on that as well. Thanks
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Re: SERIOUS OVERHEATING

Post by werewolf » Wed Jan 18, 2017 16:02

doug.. try drilling a few holes in the thermostat . so that you get MORE flow with the water.. might also check to see if you have hair line crack in the head at the water gasket.. or even something as simple as air bubble in the system.. major problems here in the southern USA in the summer as most days are 100F.. hope this helps. bc ps. I am using the 4 core alloy rads for years.. from china.. only about $50 and they hold up ( I delivered in my mini wagon for 19 years. and NO overheating even sitting in traffic ALL DAY>

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Doug G
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Re: SERIOUS OVERHEATING

Post by Doug G » Mon Jan 23, 2017 19:10

werewolf wrote:doug.. try drilling a few holes in the thermostat . so that you get MORE flow with the water.. might also check to see if you have hair line crack in the head at the water gasket.. or even something as simple as air bubble in the system.. major problems here in the southern USA in the summer as most days are 100F.. hope this helps. bc ps. I am using the 4 core alloy rads for years.. from china.. only about $50 and they hold up ( I delivered in my mini wagon for 19 years. and NO overheating even sitting in traffic ALL DAY>
What size and how many holes did you drill?
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werewolf
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Re: SERIOUS OVERHEATING

Post by werewolf » Thu Mar 23, 2017 23:00

doug.. very small ones. about 1/8 inch...and .about 6-8 will work.. btw. sure you do NOT have something as simple as air bubble in the water hoses?? tim is quite right.. you MUST have a thermo to restrict the flow.. later bc

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Doug G
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Re: SERIOUS OVERHEATING

Post by Doug G » Tue Mar 28, 2017 22:22

werewolf wrote:doug.. very small ones. about 1/8 inch...and .about 6-8 will work.. btw. sure you do NOT have something as simple as air bubble in the water hoses?? tim is quite right.. you MUST have a thermo to restrict the flow.. later bc
Will install the spare' thermostat I have in my drawer. and start with three holes, or should I make more?

Mind you I may end up going through a lot of gaskets !!!!
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Doug G
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Re: SERIOUS OVERHEATING

Post by Doug G » Sat Apr 22, 2017 20:23

Now that the cylinder head gasket was replaced, the coolant disappearance appears to have stopped as has the overheating. :D
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