44 replies to this topic

[CooperKid]

Hi all

Just seen this thread, have a similar problem myself.

Have a 1998 cooper, fully restored by previous owner.

Drove across London last Friday, all good, went to the garden centre round the corner and there was steam coming out from under the bonnet! Left it and spoke to the prev owner, who said he'd had no problems but to let it cool then run for 10 mins to see if there are any leaks. Did that, added coolant no leaks, all good. Drove back across London on Thursday (an hour) all good.

 

Then today, Saturday drove my 2 sons to meet family, 30 mins journey, all good, but steam from under bonnet on way home. Pulled over, lots of coolant in road, realised expansion tank was empty, topped up once cooled a bit, ran again, no leaks seen anywhere, drove home, 10 mins. Steam coming out again. She's now parked up fine but I've no idea what's going on! No leaks, radiator is new but coolant boiling over, a blockage somewhere? 

 

Sorry for long winded version, but thought some back ground needed. Probably a simple-ish  answer from someone who knows what they are talking about, but a worry for me.  I'm hoping it' just a expansion vessel cap as mentioned above, as all else seems good. MY son's girlfriend's dad seems to think it might be head gasket! Don't like the sound of that!!

 

Thanks in advance 

Hey Jaffa Cake (great name by the way  )

 

Sorry, only just seen your post. Have you managed to sort this now? I would try the cap and tank first as they are the least expensive parts. Biggest problem is that when you havent built the engine yourself, its difficult to know whats been installed and to what quality the work that has been done :/ 

[Chris M]

I bolted the head back on last night & as torquing it up one of the studs was pulling up on the second stage of torque & this is also where the old/new gasket had dimples in it. I guess that it wasn’t holding & coolant escapes under the gasket. I’ve cleaned up the thread as it has been previously helicoiled . Screwed It back in with loads of thread lock?

[ings]

steam is normal with the MPI.

 

i have a few tips and tricks for every MPI driver:

 

- always carry one or multiple reserv cap and two liters of water with you. (the caps last normaly 1-2 years)

in most cases the cap produces the boiling because the system can not handle the standart overpressure.

 

- even a new cap with a new expansion container  seals not correct, a SMALL amount of Teflontape around the thread can improve the sealing

- use ready to use cooling-mixtures and dont dillute this with water (water will increase the Steam-pressure in the system)

- there is a mark for the maximum level of cooling liquid, do not overfill the system

- remove the sportspack fog lights when you drive at extrem hot temperatures on the motorway

- drilling 2-3 4mm holes in the thermostate improved the cooling for me

- check your valve clearance should be 0.3mm

- normally an mpi makes 300 - 400km with 20Liters Fuel if you need massive more fuel check your Lamda sensor

- be sure the waterpump belt has the correct tension

Edited by ings, 10 July 2019 - 12:27 PM.

[pete l]

Or go to EVANS waterless coolant which does not boil and does not pressurize the system.

 

Don't ask me how though, I have no idea

[ings]

The MPI System needs  pressure. i would not go waterless... otherwise it realy overheats.

[Chris M]

Also what’s the option on leaving out the thermostat? It’s never used in the winter so should I leave it out to help run cooler?

[tmsmini]

Don't leave out the thermostat. The FI MPi needs to get up to temperature to run properly.

There is some other issue affecting the cooling system.

 

I have driven my MPi in 100 F/38 C temps, while it got warm, there were no boil over issues.

 

There is something basic, have you checked the thermostat? even new ones can be off.

Terry

[ings]

without the thermostate less water will flow to cylinder 3 and 4... the system needs this narrow passage.

[Chris M]

I’ve got a new thermostat & a new expansion bottle cap from mini spares. Also I’ve got a mobile guy coming out Wednesday morning to helicoil the thread in the block for the cylinder head stud.
Hopefully put back together Wednesday & running by the evening ?

[Steve220]

steam is normal with the MPI.

 

i have a few tips and tricks for every MPI driver:

 

- always carry one or multiple reserv cap and two liters of water with you. (the caps last normaly 1-2 years)

in most cases the cap produces the boiling because the system can not handle the standart overpressure.

 

- even a new cap with a new expansion container  seals not correct, a SMALL amount of Teflontape around the thread can improve the sealing

- use ready to use cooling-mixtures and dont dillute this with water (water will increase the Steam-pressure in the system)

- there is a mark for the maximum level of cooling liquid, do not overfill the system

- remove the sportspack fog lights when you drive at extrem hot temperatures on the motorway

- drilling 2-3 4mm holes in the thermostate improved the cooling for me

- check your valve clearance should be 0.3mm

- normally an mpi makes 300 - 400km with 20Liters Fuel if you need massive more fuel check your Lamda sensor

- be sure the waterpump belt has the correct tension

 

Even better still, get the BMW mini reservoir cap, it is a much better design.  You're right about the coolant level, I fill to about half an inch below the max line and never had an issue with boiling over. Drilling holes in your thermostat will also help with bleeding the system!

 

Or go to EVANS waterless coolant which does not boil and does not pressurize the system.

 

Don't ask me how though, I have no idea

 

Terrible idea on an MPi.  Waterless coolant runs hotter, it has less thermal efficiency, you have to remove every drop of water out your system prior to conversion, it is highly flammable and you can't top it up with water if you have a leak.

[Steve220]

without the thermostate less water will flow to cylinder 3 and 4... the system needs this narrow passage.

 

I've been reading that comment for the past few minutes and i still can't understand the logic.. On any A series engine you want the water to flow towards cylinders 1&2 anyway as they're furthest from the pump, hense dry decking. You can partial dry deck the system by plugging some of the coolant passages around cylinders 3&4 (MED told me about it, but i was extremely hesitant).

However the thermostat and its housing has no direct influence on how the coolant passes through an MPi head as all its take offs are at the housing.

[Chris M]

Great information guys ? what type of coolant should I use? Blue? Pink? Green?

[romblu89]

Been having the same issue after I changed the radiator and water pump. I changed the radiator as it was not performing very well, the fan was constantly turning on to keep the temps down. Since I’ve changed the rad and pump temps are much much better while the engine is running. I can barely get it ti go over 98 degrees while driving. It only goes above a hundred while stationary or after turning the engine off.

However I can’t fix the bubbling issue. New thermostat, pump, rad, bottle and also used a bmw mini cap. I checked the temp today after turning the engine off, it goes up to 105 and of course it doesn’t stop until it goes below a 100. I checked the temps using pscan.

Hope you fix yours! I’m using coma g30 (pink)

Edited by romblu89, 19 July 2019 - 10:09 PM.

[Steve220]

Comma G30 or G48 will work. Comma themselves recommend G48 for the classic mini as it contains silicate inhibitors.

[romblu89]

since its relatively the same issue I hope you don't mind me adding this here