Smelled coolant, looked under the hood with UV flashlight and found it right away. It was in the upper left of the header tank where the tubes penetrate it. It looked like the second and third tube down were the ones leaking. I looked at the radiator change videos and saw that I had to basically take the whole front of the car off, and since I hate doing car work outdoors in the winter (in the street because my apartment complex doesn't allow car work) I concocted another way. In the Navy we used to repair nuclear reactor valves on submarines with JB Weld. Well, that didn't work because I couldn't get it in between the header and tubes where I needed it. I decided to get serious. I drained the system to lower the coolant level below the leaks. That worked. Then CRC brake cleaner to clean off the area. Then I put some cardboard at the back of the radiator to provide a backing. Then, I took one of those 5 minute epoxy that have that self-mixing nose on it, put it back against the backing and filled the top five header/tube gaps. It was cold so I'd warmed the engine and held the epoxy in my hand for half an hour so that all would be above the winter cold to help set the epoxy. Success. I use a non-water coolant that allows me to run zero pressure, so I wasn't concerned about pressure, but the stuff is a bit pricey and I don't like seeing money on the ground in the morning.

 

Sounds like an interesting patch...

A few things worry me. Can you clarify?

1. "In the Navy we used to repair nuclear reactor valves on submarines with JB Weld." - Daymn... what is now known cannot be unknown.

2. Epoxy may not be the best for high temperature swings and vibrations. Hopefully it holds for you. It sounds like it's not at a major intersection of both so you may be lucky.

3. "I use a non-water coolant that allows me to run zero pressure" - Care to elaborate? With the W11 engine (Iron and Aluminum) we're supposed to use the blue Mini coolant.

4. What do you mean by running zero pressure? The pump moves water through the system - pushing it along - under pressure.


BTW, removing the MFE isn't really that bad, but without a garage - I get what you're saying.
The first time I did it, it took me 1/2 hour. I just did it yesterday, and taking my time it was 40 mins. For me yesterday the worst part was the seized/rusted bumper skirt screws.

 

Do you have a cooper or cooper S . I would replace the rad, it might leak later down the road at the seam.

What coolant ? You have to circulate the coolant with the pump ?

 

Penny-wise, poud foolish....or tripping over a dollar to pick up a penny....
spend the $100 on a rad....heck the "Evans water-less coolant" kit costs more....
and if it leaks...you are out another gallon....and maybe a motor......
Guess it works...for now...but you spent time and $$$ that is lost as it is a band-aid fix...
Good luck...hope it stays bubblegumed together..been there, done stuff like that...it usually comes back to bite ya!! And at the worst time.....
guess we all do what we need to do....but still....a $100 fix from rockauto.com compared to a $1500 fix PLUS the $100 if it overheats.......

 

2005 Mini convertible, non-turbo. Over the years I have fixed several radiators this way and never had it fail, but that doesn't mean... Anyway, prepping the surface correctly is 3/4 of the battle, rough it up and clean with solvent. Let the JB set a bit till it is a bit putty like then press it into and through the leak. In the Navy we'd repair reactor valve seats with JB Weld. Prep the area, apply the JB and machine the surface. It worked at 1,000psi+ and pretty high temps. I will replace the radiator once the nice weather hits in the spring because it looks like the source of the leak was internal corrosion caused by - water containing coolant, water being the corrosive element. Yes, I use Evans waterless coolant and have used it in everything I've owned for a decade with zero issues; scooters, motorcycles, Miata, Tercel, Mini, generators. I use it for many reasons; it's lack of corroding water so that should mean no more corroded radiators or heater cores (I hate changing heater cores), ability to run zero pressure except for the pressure head of the pump (most of the pressure in the system occurs at the restriction of the thermostat so there is very little at the radiator inlet where the leak is, higher 375F boiling point, slipperiness so it lubes the pump seals nicely. I don't use the Evans 'kit'. I just empty the system, flush with water two or three times, then put the Evans in with the little center valve on the radiator cap removed. I monitor coolant level as the remaining water steams out over about a week or so.

 

You don't use the prep solution to get the water out? While most folks can use compressed air to blow out the last few drops, my understanding the prep solution is an important part of the conversion in that it help to dry out the system...
Yeah...it is neat stuff....but automotive coolants have come a long way too...the current crop of how long life coolants last almost as long as most cars are on the road.....mini switched the standard blue to a hoa a few years ago...but older cars still have the older formula that is only good for 3-4 years till flush....and most folks ignore the need ..and stuff corrodes like hell...
The failure where the aluminum core welded in the plastic to the side tanks seems to be more related to the plastic getting brittle from leaching out plasticizier as it ages and getting hard...pretty common on the plastic/metal design...

 

My leaks are at the cross tube to metal part of the header tank, and at the top left where the coolant enters the radiator and is hottest, so I'd expect corrosion to happen there. I'm just hoping that no more weak spots show up before spring or I may have to pay a shop to do it. Arggh! The prep solution; I finally got an Evans tech to admit it is not required and that my method of letting the residual water evaporate out over time is OK. I learned that from a racer, he just took the 'pet safe, environmentally safe' coolant and poured it in the system (w/o water) as a flush, and it worked just fine. Me, I just flush with water, drain as much as possible, then put in Evans. I still have a very tiny leak, and I do mean tiny as a few drops a day on the back side of the radiator so I'll have to try the epoxy on that soon.
I have a question, to change the radiator do I have to empty the A/C system to do that? I hope not.

 

Nope...you can just unbolt the condenser and fold it out if the way...keep it supported, but no need to drain the ac.

 

YAY! And thanks.

 

This is depressing. I had this leak at about 110k. Replaced the radiator and now less than 25k later the leak has returned in the exact same place on the new radiator.

 

What brand radiator did you buy? Was there a warranty? 25K sounds like about a year of driving.

 

I recall it's a Behr, from ECS.

 

Well, I've decided that the epoxy succeeded in reducing the leak to a seep, like less than an ounce a month. I can deal with that till the weather warms up. So, the plan is to replace the radiator. I will also replace all the hoses and since I have to take the front end off the car I should address anything else that is behind the radiator, so I'll replace the crank angle sensor O ring, should I also do the sensor itself? What else do you folks recommend dealing with?