Freeze plugs are referred to as core plugs because with castings having hollow interiors (coolant passages), They need casting cores to form the voids. This is usually sand that has been formed and compacted to the desired void shape. It stays in there until the molten metal has set and cooled. The casting sand is then washed out through the necessary openings. The openings are machined to receive the steel plugs, which are pressed in. Their shape allows them to expand with the block and maintain a seal. They can withstand internal pressure but usually not ice. They aren't a guarantee against the block cracking when the coolant freezes because the coolant can freeze in passages before a plug pops.

Awesome, thanks Malsal.  I looked around in the parts section and found the core plugs, but didn't know if that was the right thing or not.  From the pictures it looks like the plug is located on the rear of the engine opposite the rad and fan but my drip was viewed from the left front by the rad and water pump.

Freeze plugs or sometimes called core plugs are located in the block there are several sized differently. 
If the water in a cylinder block freezes and expands they fail which in theory saves the block from damage.
It is not 100% though I have seen blocks that have frozen and cracked between the freeze plugs.

I've never heard of a freeze plug.  Can you elaborate please?

I certainly intend to check the hoses for sure while I'm down there and have it all apart.  I'll also be inspecting for where the oil is leaking from.  I would be nice to not have to worry about a drip tray any more.

sounds like it might be a freeze plug and not a water pump problem

Check that lower hose too while you are in there. It has about 4 or 5 connections that can leak too.

Awesome thanks very much!

 Mini mania # GWP 154, water pump has no by pass. It can be drilled if you need to.

Can anyone help me get the correct water pump for the Mini?  As far as I know its just a normal stock 1275cc A+ 1993 SPI from Japan.  Did they have a variance between the pumps on the years?  Some with the extra hole, some without, or the coolant bypass.  I'm not sure which I need.

You need a new water pump.

Quick update, I had checked under the car and a fair amount of antifreeze flowed out.  I refilled with plain ole hose water and ran the car up to temp and let sit, cool down, open the rad cap....  Nothing came out.  I went for a couple short drives and temp never rose past just below half way (normal for the car ever since I've owned it).  My wife had her car in the shop and took my Ridgeline for herself so I daily drove the Mini 30 miles to work, 30 miles home for all last week.  No issues whatsoever.

I do still want to check out the water pump and probably replace it, just in case.  I also will have to drain the water out for winterization.  But I'm wondering if maybe something clogged the "hole" antifreeze was leaking from?  Or is water not as molecularly small as antifreeze?

It is merely sweat from all that horsepower!!

Nice to rent a ' radiator pressure tool. from Advance auto or Autozone..

Add pressure to system start looking for the driibble.  Follow it to the source.

 More than likely Waterpump.

Don't worry about the by pass hose comment as the 1275 does not have one fitted.

I'll check, I took the grill off and that is where I saw it running down the block, but couldn't pin point further.


Sorry about that.  I've got a 1993 SPI

You don't indicate what year your Mini is or what engine you have.

If it is a small bore it could also be leaking from the by pass hose which is best to replace with a small piece of 1/2 id heater hose.

Yes the anti freeze mixture on the belt could cause it to squeal.

Yes, there is a drain hole at the bottom of the water pump.  Take the grille off and you should be able to see the bottom of the pump (out towards where the fan goes) and should be able to see any escaping fluid.

"I also noticed my belt now squeals.  Could it just be rad fluid on the belt, or the water pump pulley causing the friction?.."

If you loosen the fan belt you should be able to reach up and turn the pump to see whether it feels stiff/notchy ..or otherwise not healthy ..

Cheers, Ian

I replaced the radiator when I first got my Mini in 2016 and hadn't had any issues up until a few months ago I noticed the oil drip pan under my car had green rad fluid on it.  I don't get much time to inspect but have noted when I open the rad cap the flow increases to a steady drip.  After dripping enough and creating a vacuum the drip stops.  I've seen it running down the front of the block coming from around near the fan pulley area.  Would this be the water pump seal probably went bad?  Any other things I should look for other than the obligatory "check the lines" since I'll do that too?  I don't get to drive the car much anymore, but I move it out of the shop and let it run once in a while and never have any smoking.  Even topping off and going out for a drive, the car never got hot or smoked.

I also noticed my belt now squeals.  Could it just be rad fluid on the belt, or the water pump pulley causing the friction?