I recently purchased a MKII Mini, I was told the motor was from a 1975 mini and it has pot joins on the in board side of the drive shafts so it is believable. I just got it running the other day and all seemed fine but then today I drove it to work. On turning into the office drive the interior was starting to fill with steam/smoke. I was able to fill the radiator and make it home. So I started trouble shooting... I let it cool, refilled the radiator and cranked it up again without the top on. It seemed that the coolant wasn't flowing it would move up and down some but never seemed to flow. I was hopeful maybe a bad thermostat. Shut it down let it cool. When I came back the coolent was gone out of the radiator again... So fill it up start it again and watch the level. This time I let the motor run longer watched similar result but after I shut the engine off it sounded like boilling down in the depths of the motor somewhere it did this until the coolent was no longer visable in the radiator any more. the only steam I saw was from the breather from the valve cover to the air filter. Which should not be connected to the cooling system .... I mean I really really hope they are not connected. I also checked the oil for coolent and it looks super clean I have a reciept from the last owner getting the engine rebuilt one year ago.
HELP....

 

Lots of possibilities here and questions ... You say you just got it running? OK, that's possibly beside the point. These cars run HOT, you'll find LOTS of posts out here on overheating. I was driving mine home after purchase when it overheated and blew a radiator hose (a royal PITA to replace).

Where is your coolant going? Is there a noticeable leak underneath? Is the heater core leaking (is the carpet wet inside)? It shouldn't just vanish and it takes a while to steam it away. It sounds like the coolant level was and still could be low, since it seems to vanish into the block (or somewhere else).

Personally, I think you're on the right track with the thermostat, they are notorious. If I lived in FL, I would seriously consider removing the thing.

There are others out here with a LOT more experience with these cars, hopefully they'll chime in. You might also check out the MiniMania forums and search for overheating.

Best of luck.

 

When I purchased the car it would not start cranked over but not fire. I replaced the plugs, wire, cap, points, coil... and rebuilt the carburetor.

As far as coolant I don't see any leak the only thing leaving is the steam escaping from the breather going to the air filter.

http://www.flickr.com/photos/58461956@N03/5375356767/
This link shows the motor and where the steam is coming out.

Also I was told by the P.O. the heater is not hooked up and you can see in the picture the heater hose is connected up to another hose but I don't know if that is ok or not.

 

Can't see what fan you are using but trade it for the 12 blade fan this might help. Works well in my cooper s with richard longman race engine. Better picture of where your circle would also help.

 

Yeah the picture is not great Sorry I'm at work and I bought this car through ebay and that is one the picture put up by the seller.
Here is the link

http://cgi.ebay.com/ebaymotors/ws/eB...ht_1264wt_1141

It has the plastic yellow fan I think is the twelve blade.
I don't think that the issue is air flow though I could be wrong. I'm afraid the problem is deep in the bowels of the motor perhaps I over thinking it? I can't get over why the coolant disappears after I shut the motor off? Tonight I'll try to post a video on flickr that my help???

 

Ther is a pipe fitting on the left front of the engine near the front head bolt. If that is a water hose going to it take the hose off and see if the pipe fitting is pluged. If it has not run in a while the fitting might be corroded and closed off. Just a thought.

 

Thanks I'll take a look at that after work. Should be fairly quick and easy to check out.

 

And if you get a hose loose, you can leave it just loose enough to start the engine and pull the hose while running to see if you're getting flow. You'll make a BIG mess, so you want to try this outdoors and cover yourself because the water should be HOT.

Here's hoping you have a plugged line or thermostat.

Does the engine run well and what sort of stuff is coming from the tail pipes? With ANY car, one source of mysterious overheating and steaming away coolant fluid is a blown head gasket, but that will usually manifest itself in poor engine performance and lots of gunk from the tailpipe (if the engine runs at all).

 

I just got the car running last weekend and only took a couple trips up and down the neighborhood not more than a mile each and with time between them. The first time the car started it smoked (out of the tail pipe) a lot. by the time I returned from the first drive less than a mile it was significantly less. Then less each time after until is was not smoking and continues to not smoke from the tail pipe now. I checked the oil for coolant thinking a possible head gasket. I haven't had any experience with small British engines I was a big American power guy. My last play car was a 1971 Corvette (years ago). So I believe the engine seems to be running well but I have no base for comparison. When rebuilding the carburetor I did lean out the mixture a bit because the plugs were fouling with to much gas when I got it.

 

I can't believe the coolant is all boiling off. I too had an overheat while taking my 79 home the first day. Boiled over real nice. But even that only lost about 1/3 of what's considered full.

Mine WAS a stuck thermostat. I used an old bottom of the seats trick - I whacked the housing firmly with the handle of a screw driver and I've never had another cooling problem!

OK, took a while looking at your pictures but it appears prev owner just took the two heater hoses and spliced them together. They are so high up that there is probably an airbubble in there inhibiting flow; you have a connecter up high so you could try bleeding while the system is pumping. Also it appears the heater valve is open, try shutting it.


I'd flush everything . . . I'll bet there's a ton of crud in the system that a simple backflush will at least begin to clear out. I use one of those little Prestone kits about once a year.

When the coolant 'disappears' how much are you putting in to bring it back up? That fluid is going somewhere, I can't believe it is boiling off that fast.

Take it for a drive warm it up then start looking around under the bonnet I guess . . .

The one blown head gasket case I've seen on a Mini did manifest itself as milky oil pretty quickly. If you lost significant coolant that way, heck the level would go up!

 

Capt.
I don't think it is all boiling away. Its just I can visibly watch the the filler neck and see the top of the cores, and after I shut the motor down I hear what I think is boiling and see steam and within ten minutes I can see the top of the core with no coolant over it. I'm guessing it takes about 2 quarts to fill it back up I'm sure not the entire volume.
Does anyone know it I can just cap the heater hose? As there is no heater in the car and I hopefully won't need one until next year I think it maybe best to take them out of the equation? My guess is that it would be no different than a car without heat, so the only pluming I would need should be thermostat to radiator and radiator to water pump.

 

Total volume for the cooling system with the heater in place is a tad under 4 quarts . . .

To me, closing off the heater loop seems doable but I haven't tried it.


Could it be that when you drive you have a spray someplace that's boiling off? Then when you stop the volume is LOW and you have problem beginning from there?

Question remains where is the coolant going

A SEA STORY

{Yes I really was a ship captain.}

In the first weeks of my first sea command we had just left a fueling stop and were about an hour out of port when the engineer came to me and said, "Captain, we have to turn around and go back because we have no fresh water."

Now I knew that an important job at any port was to top off the water tanks and I was told this had been done which EO confirmed.

"How did you manage to pump all the water over the side", I asked.

"Oh, we didn't do that sir . . ."

"Well if you are missing 15,000 gallons of water, and you did not pump it over the side, it must be on the ship in a place it does not belong. FIND IT."

After a couple of hours of searching and researching the pipe prints the EO discovered a new way to pump our water overboard .... or I should say he found the way another had found via a misaligned valve.

Meaning . . . it does not disappear by magic . . .

 

I quite agree.
On my drive home from work yesterday I filled up before I left and drove @ 4 miles home some water was on the fire wall/back of the engine bay where it sprayed out of the overflow.

While I was running the car with the cap off to watch it some overflowed out of the top of the radiator with the kind of typical up and down pulsing you would expect from a cooling system with out its cap on.

However after I shut the car off all I can see of water excapign is steam I looked under the car and there are some drips but no more than can be attributed to the overflow while running.

 

Ahhhh new guess

pressure is opening a leak in a hose . . . with the engine off, you can't see it

with the cap off you can't see it either cuz there's no pressure

put a plastic tube on the overflow to route that away and not be a confusion factor

 

At this time it might be best to replace all hoses Rad,heater and any other rubber hoses to make it a truely inclosed system. And a good radiator flush with an approved cleaner and then as Capt says a good back flush.

 

Okay,
I'm shining up best optimistic out look here. I went to capture a little film of the radiator level dropping while steam came out of the crank case but... that didn't happen.
It appears I have a leak as I was more careful about making sure the water got in the filler without spilling. I cranked the car and notice water coming out from under it as the level went down while the car was running. I doesn't leak while cold.
Other wise the fins of the radiator look nasty covered with undercoating? possible 2 owners ago they seemed cover up a bit of problems a lot of poor quick repairs and undercoating everywhere underneath even over the rust.
Could be burnt oil residue? or just road crud.
So I'm going to try taking it out cleaning and flushing it and new hoses I might go ahead and pull of the water pump and give it a once over, while I'm in there.
Thanks for the help I'll keep everyone up dated.

 

Sounds like corroded radiator with little pin holes that just evaporates the water as you are running the car......radiators and hoses are not to expensive and I would replace all of it. To get a good operating temp, go with a 3 or 4 row radiator as these will help with controling your cooling temp

 

So Sunday I sent about removing bits and pieces of the cooling system.

I got the radiator out I didn't find it to be as big of a chore as I read people make it out to be. The last radiator I removed was for a Chevy 350 out of a 71' vette. So while space is certainly at a premium I really like that I can man-handle the Mini radiator with one hand while doing something else with the other. The Vette radiator was a monster to get out by ones self.

Speaking of man-handling I'll have to post a picture later but the aluminum thermostat housing corroded itself to the steel post and I broke into 4 pieces trying to remove it.

The radiator as I mentioned has some serious oil caking on it and I'll take it the the local shop to have it cleaned and tested.

I'll also get a new thermostat (and housing) and hoses and put a plug in the heater takeoff from the head as their is no heater matrix installed in the car.

I'll put up some pictures soon I hope and let everyone know how it is going. Thanks for the suggestions.

 

You should think twice about plugging off tthe heater takeoff from the head. If you do the number 4 cylinder (where the heater take-off is located) will have inconsistent cooling from the number 1 to number 4 cylinder. I deleted my heater and plumbed a coolant return line from the head back to the hot side of the radiator (see below URL). Of course this will require adding a bung to the radiator to connect the hose.

http://tsunami.desertwave.com/galler...serialNumber=2

Hope it helps,
Jeff

 

which if you check his pictures is what he has now ... not an elegant job, but that's what's been done using the standard hoses and a splice. Perhaps with so much rise in the hose run as to build an air trap . .

But the concern as to why not do it is noted

correction the current piping appears to be standard with the heater core removed. I don't see the advantage of a loop taking the coolant from the top of the block and sending it back to the thermostat if I'm following your suggestion. What's the difference between removing the heater hoses entirely and blanking off the connection versus driving with the heater off all the time - that is, the valve closed? I sure never use the heat here is Fl .... and have no cooling issues btw.

 

Capt mine currently or at least up until Sunday ran from the heater take off at the head to the lower radiator hose. This should be the cool(er) side of the radiator use less my thinking is wrong. So I can reason that the heated coolant from the head take off was never making it back to the radiator. Jeff talked about plumbing back to the hot side the upper hose, again unless I'm trying to make the radiator flow backwards. This way it could be cooled be for being returned to the engine. Jeff the picture only showed the head side at the take off, where is the return the top or bottom?
Thanks...

 

Capt,
I agree with your thoughts about blanking the heater being the same as driving with the heat off.
At least for the sake off ferreting out the problem I think to simplify the system will be advantageous.
After I make the car keep cool for drive to around town I can worry about the advantages of cycling in the coolant from the heater take off.

 

Below is a URL for picture of my current setup. I didn't post this before because I've installed a 2nd radiator and it complicates the hosing a little bit. From the picture you can see the coolant exits the head at the heater valve location and enters the 2nd radiator (aluminum unit mounted on inner wing), then exits the 2nd radiator and returns to the hot side (top) of the stock radiator.

To answer your question - the mini's top radiator tank is the hot side (coolant traditionally leaves the block via the thermostat housing and is dumped into the top of the radiator. It cools at it works it's way down to the bottom of the radiator where the water pump sucks it into the block.

http://tsunami.desertwave.com/galler...serialNumber=2

Hope it helps,
Jeff

 

I agree with Jeff on this one.

i went through this issue with my mini when i was building it and if you take out the heater matrix out of the loop then the coolant capacity is too low and it will not allow your whole cooling system to cool down properly. i ended up doing something similar to the pic Jeff posted.

also since you have the rad out, it might be a good idea to consider swapping out you stock fan for a tropical one (if it hasn't been done already) and maybe adding a switched auxiliary electric fan between the rad and the inner fender to pull air through if your suck at the lights or in traffic.

 

nuff said . . .

best option is probably to insert a better/larger rad.

Having the heater in but the heat off is kind of a wash huh?

and all those things we talked about????

MiniWorld ... if you dig deep enough says install a modern rad if changing things BUT the standard system will keep up with demands.

Many cooling fixes just hide the problem via the addition of new cooling tools.

Best option is prob' t dip the rad' and find out how effective it is. Did you say you thought it had UNDERCOATING on it?