So my 2007 base cooper engine expired last week, suffering an instant meltdown. Turns out a frost plug on the block "fell out", immediately filling the crank case with water. Has anyone else heard of this happening?

 

(Based on my limited knowledge)
Not sure how this would fill the crank case. Core plugs, sometimes incorrectly called freeze plugs or frost plugs, are plugs that fill the coolant core holes/passages. The purpose is to protect from cracking the engine block due to freeze damage. As we learned in science class; water expands when it turns to ice, and if the coolant does not have enough antifreeze protection it can freeze and crack the engine block. The freeze plugs (there are usually several) are supposed to pop out under such conditions to relieve the pressure on the block. As these expansion plugs are usually located on the external side of an engine block, I am not sure how the coolant would end up in the crank case.
You may want to get a second opinion on what caused the problem. Is it possible there was just water (i.e. water with no additives like Water Wetter) in the system for coolant? I suppose a plug might pop due to excess pressure, though very unlikely as the radiator cap is designed to release the steam pressure before it gets to that extreme.

 

This is very odd, even if your out of warranty I would talk to MINI being such a rare problem they should warranty it, cause that is a defect.

 

Actually those holes are used to get the media out of the passageways when casting the block. They just fail sometimes. Typically it can be from incorrect installation or corrosion. Sometimes the incorrect sizes are installed.

 

The exact thing just happened to me. 2010 base. Freeze plug just below the cam sprockets came out and filled the crank with water. WTF!!! A 50 cent part. Thinking of plugging the hole with an aftermarket rubber compression plug.

 

Hey! My wife's 2010 Cooper HT just did the same thing! I'm not sure what happened, exactly. She called me a couple miles from work saying that it was overheating and kinda running funny (her words). Despite my telling her to NOT TO, she drove it again after work until it stranded her. Compression is good, no steam from tailpipe, runs fine, plug popped out and landed on chain guides (that was lucky). Pan, etc. full of coolant. It doesn't appear to have caused any serious damage, but I won't know 'till I can fix the plug problem. In all my time of working on Land Rovers (mostly), I've never had a "freeze plug" pop out. Any ideas? I think the cooling fan quit working and caused it to get hot which may have caused the plug to pop, but REALLY?

 

Pure guesswork, based only on the last 3 posts, but I'm thinking all 3 blew a head gasket because that's about the only way water & oil can be mixed.
The resulting over-heating caused the core plug to pop out after the damage was done.
Was it the same core plug on all 3?

Why would this happen on recent, low mileage cars?

Mike - MVPeters at comcast.net

 

Head Gasket was fine. I fixed mine. Had to remove the outer block plug to get to the inner one. Pressed in the new inner with RTV to seal it up and then pressed in the outer plug.

Took 4 oil changes and 3 coolant changes to flush everything out.

 

The same thing happened to my 2010 mini when I call my mini dealer they told me that I could not get a new plug and that I would either need to change the head or drop in a used engine. My warranty was up so they would not cover it.

 

I saw this once on a Justa that was still in warranty. MINI replaced the engine, probably so they could analyze problem.
MV, this head design has a water jacket with an opening behind the cam gears. since the gears are chain driven, coolant would fill crankcase rather than leak externally.
The casting hole is sealed with a metal plug. It will fill crankcase with coolant almost instantly when plug comes out. This engine was hydrolocked and would not turn.

I thought it was a fluke at the time, but it appears that it has happened before.
Diluted coolant could certainly be the culprit if all these cases occurred during cold weather.

 

To the moderators, this thread should be moved to 2nd generation as 2007-2010 models are all N12/N14 engines.

 

ty.

 

There has been a member with an S that had this same problem, freeze plug under/behind cam sprocket fell into the oil pan coming into contact with the connecting rods and flooding the oil with coolant! He got lucky no serious damage was caused, cost him under a $1 to replace the freeze plug.

 

Ya, I remember reading that thread. He also included some great pix cause everyone couldn't figure out which one he was talking about. As I recall, he ran into problems replacing it (was hard to get to).

 

It seems to be a rare occurrence far as long as I have been hear, until now that one was the only time I heard of somebody losing a freeze plug internally. I think that's a good thing.

 

My 2009 Clubman just died when a freeze plug in the head fell out. Serious damage to engine necessitating rebuild with new exhaust valve, radiator, water pump, thermostat,head gasket, etc at a cost of $4000!! Out of warranty so Mini sez sorry. Any recourse???

 

Approximately 2 months ago, per the Mini Service Manager of Mini of Fairfield. "The freeze plug fell into the engine compartment, causing a catastrophic engine failure." This was not a Head Gasket problem as some have eluded to. This info came straight from the service center. They quoted me a minimum of $7700 to fix the engine with no guarantees or $11,00 for a new engine. In my travels to purchase another Mini (don't ask me why) every service manager at every dealership I had visited had heard of this happening, but have not heard of any recall regarding the problem. BMW recently instead of recalling cars settled a class action lawsuit regard the chain tensioner. Was probably much cheaper and quieter to do it for this way. To date I have not heard of a Class Action Lawsuit regarding the freeze plug, but would be the first to sign up if one does arise. After numerous phone calls and Emails to Mini USA cooperate, the only thing the were offering was $1500 towards a brand new or certified preowned. I bought another Mini (used) from a Mini dealership but the Corporate would not refund $1500 because the car was not certified preowned. The Dealer ship, Mini of Morristown, NJ... said they thoroughly check over their cars but do not routinely certify their cars because it's an added expense to the dealer ship that they feel is unnecessary. Regardless $1500 would in no way replace my car. Other then the engine my car was in spectacular shape. This car was garaged it's whole life. I even had it wrapped in clear vinyl to protect it from nicks and scratches. Now it's just a paper weight in my driveway. I think my next step will be to contact national public radio or some big media corporation. They've done some interesting stories. This one might appeal to them. I get the feeling Mini Corporate thinks I'm just going to give up and move on... guess they don't know me very well.


PS... Mini USA public relations person SUCKS! Very surprised how they talked to my wife, she was pretty upset. I'll personally deal with that another time.

 

Quoting the repair order:
Removed valve cover and found that one of the freeze plugs underneath the camshaft gears had fallen out.
$4600 to repair.


The car does have an incredible amount of mileage on it...all of 65,000.


That is some awesome German engineering.

 

Having some similar issues with my daughter's 2007 (purchased used at least two previous owners), I've replaced the coolant pipe (thermostat to water pipe connection) which WAS bad, but still experiencing some coolant loss which I originally chalked up to the system still burping air, but now have discovered a slow drip from behind the exhaust manifold gasket. Starting to worry that it is head gasket or cracked head...someone has definitely been in there previously from what I've encountered in disassembly. haven't removed exhaust manifold yet...but I'm there, it's the next step. What's interesting to read is all the folks who are saying this is common and have such relatively low miles...I have a 2008 with 215K miles, I've driven it hard, but pay attention to it...this car is a beast, I love it. That was my experience when my daughter purchased her car, it has had some issues, I'm starting to think that too many people buy cars and drive them until they breakdown and never interact lovingly with them prior, or maybe I just got lucky???

 

any idea where that thread is? Curious to see if he referenced which plug he found that would fit. Thanks

 

aloha everyone,

first, thanks to all who post and share... often very helpful for many fellow MINI owners
I thought I would add some detail that was missing in my search for answers....

My MINI: 2010 R56 Hardtop Non-Turbo N12 engine 80K miles

I also experienced the dislodged freeze/core plug due to engine overheating BUT my freeze/core plug was not located on top of the engine under the valves like others (here and elsewhere) shared. After some searching, I found that my core plug was on the side of the engine in the timing chain well (see pic). Hope this helps others with the same engine

More details of my situation

My MINI overheated several months ago. I found some leaks at the coolant hoses, so I replaced all of the coolant/heater hoses, along with the thermostat and gaskets. A few months later, my engine overheated again, but this time I could not find any leaks - just an empty coolant reservoir. So I refilled it, and kept refilling until it took more than the system's capacity. At that point, I checked again and found no leaks. Knowing that the coolant had to be still in the engine, I did some research. Posts like this one and others helped me focus on confirming a dislodged freeze/core plug was the likely culprit. After removing the valve cover, I wasn't able to find any plugs on top - which confused me. Then I found a good suggestion > blow air into the coolant reservoir which allowed me to hear and see the "chocolate milkshake" (oil/coolant mixture) flow out of the side of the engine under the timing chain.

In my search to repair this situation, I found 1) MINI doesn't sell the plug by itself - you have to buy a new cylinder head, 2) there were some (mostly in Europe) who replaced the plug by sourcing or manufacturing one (not one of my skills) that had threads (theory is that it would be harder to "pop out", 3) I wasn't able to locate/source a new plug (and even if I had, I would still need to take my engine apart and inspect for any additional damage - plus fully flush out and clean.

At the end of the day, my choices boiled down to 1) sell the car as salvage and spend +$15K to get a replacement MINI, 2) have MINI or 3rd party shop fix (costly), or 3) buy a remanufactured engine (not rebuilt) and replace myself. I decided to go with option #3, least expensive, plus my son wanted to help so it became an opportunity to teach him a few things about cars while enjoying some father/son bonding. I also figured that this would essentially reset the "lifespan" of my engine.

I found a reMFG'd engine locally for under $4K and I spent another $1K on replacement gaskets, o-rings, fluids... plus replacing the ignition coils which were submerged in oil/coolant and the oil filter housing (which I found a loose o-ring inside the filter housing - tech notice says you have to replace the entire oil filter housing when this happens... plus new spark plugs, fuel injectors and clutch just so I don't have to deal with those in the near future.

Current status: Waiting on oil filter housing (supply chain delays)... the other components have been reinstalled on the new engine (it's a breeze while it's out of the car on an engine stand). Looking forward to putting this new engine back in and connecting everything else back up, refilling fluids and firing the new engine up. Plus my son has started to work on his car (ie: oil change, new brakes, etc.)

Lesson learned: Check oil and coolant levels AND look for signs of leaks REGULARLY. Like many, I got lazy and didn't realize there were symptoms until my engine said "ENOUGH ALREADY" lol

aloha!