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Mini Overheated...what Now


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#1 luismx123

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Posted 06 August 2018 - 09:10 PM

Hey guys. I screwed up. Long story short (long story will be written up soon for anyone interested), was a 750+km journey. 15-20km uphill and motor overheated cus I messed up.

Car started losing power, spotted the heat meter pretty high. Pulled over.
Opened hood....smoke.... Not too much,but the "smells bad" smoke type. Slight bubbling around head gasket and rocker gasket. Slight oil loss and few drips under car. Waited 1-1.5hrs to let it cool. Opened radiator.....empty. filled in 1L of water that I had in the car. Let engine cool off way down. Tried to start car. Took quite a while (close to giving up). Pumped the gas a few times and it jumped on with a rough and low idle.... rolled in 2nd 1km to gas station. Filled up radiator full. No drips. Drove home.
Got home, checked rocker filler cap. Slightly melted inside from the heat. Car drove perfectly after I refilled radiator...idle back to normal.

My questions: should I be concerned? What can go wrong? What did go wrong (maybe someone has experience)?

I know I screwed up. It hurts enough to see Milo in that shape...

Edited by luismx123, 06 August 2018 - 09:12 PM.


#2 nicklouse

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Posted 06 August 2018 - 09:22 PM

could have been anything. do the basic check. timing. compression, valve clearances. and check your water before every drive now.



#3 unburntfuelinthemorning

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Posted 06 August 2018 - 09:45 PM

And if all of the above check out maybe fit a radiator expansion tank if you don't have one.



#4 cal844

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Posted 06 August 2018 - 09:51 PM

Change the thermostat... We had it on a mates car where the engine Temperature would be ok one minute then spike through the roof... To get the car home we removed the thermostat, then just kept checking the level.

The only change the owner had done between runs was to delete the heater matrix portion of the cooling circuit.

As stated in above comments try an expansion tank and changing the thermostat

Edited by cal844, 06 August 2018 - 09:51 PM.


#5 harrythehat

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Posted 07 August 2018 - 06:26 AM

A series engines are pretty bullit proof.

if they had ally heads then you would have a problem, but cast iron to cast iron you should be ok and not blow the head gasket, if shes running ok and you've sorted the over heating then just keep an eye it could show a leak a couple of hundred miles down the road

if it does go its not a hard job, longest bit is getting head skimmed, otherwise its a few hours work



#6 luismx123

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Posted 07 August 2018 - 06:45 AM

Change the thermostat... We had it on a mates car where the engine Temperature would be ok one minute then spike through the roof... To get the car home we removed the thermostat, then just kept checking the level.

The only change the owner had done between runs was to delete the heater matrix portion of the cooling circuit.

As stated in above comments try an expansion tank and changing the thermostat

Will be looking into this. Not sure what the thermostat does (total car nooby), but will have a look. 

Im wondering where the coolant when. If anyone has an idea that would be great. Ive narrowed it down to: a leak which I canot find - as i got up this morning and the level is the same as I left it last night, or the radiator losing water through the cap - possible evaporation?? Have an MOT exam in 3 weeks so Ill have a closer look after all that. Will probable take the car apart over winter and learn the ins and outs and give the radiator and cooling system a flush, clean up the insides a bit, maybe swap some pieces out etc. 

 

And if all of the above check out maybe fit a radiator expansion tank if you don't have one.

Having a good thought about that too. Will see how the coolant holds for now. Maybe - if I ever have to drive 750km again - Ill smack one in as a safety measure. 

 

could have been anything. do the basic check. timing. compression, valve clearances. and check your water before every drive now.

 

From my non-existant mini knowledge: I checked the oil level - was perfect. Checked the inside of the rocker through the cap hole. No white foaming from water (a guy at the tank station told me white rim or white foam means water has gotten into the engine. big booboo if that happens), checked the liquids this morning and it looked fine. Over winter Ill probably ope up the rocker cover and swap gaskets etc and learn a bit more about the motor. Will need to google the compression test and see how thats done. 

Also, could the sparkplug get problems from overheating? engine runs pretty much perfect, but maybe as a precaution should I swap them out?

Thanks too all for the replies. 



#7 nicklouse

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Posted 07 August 2018 - 06:55 AM

I would say now that it just got too hot, through the big climb. or the thermostat got stuck but is ok now (strange but possible). if levels are good then no leak. so got hot and blew it out of the cap. cap could be incorrect or faulty.



#8 russo

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Posted 07 August 2018 - 10:51 PM

Leak down test will tell you how the rings and valves are, also weather head gasket is OK or not. If all tests OK, drive it for a while on shortish runs checking the oil and water after each run. Don't panic, you may be lucky and caught it in time.



#9 Bat

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Posted 08 August 2018 - 08:29 AM

Hi,

I would change the radiator cap and the thermostat when you get chance, just as a precaution really.

Cheers  :proud:



#10 Ethel

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Posted 08 August 2018 - 08:44 AM

Hot enough to boil off water isn't very hot at all. It'd be worse if it'd lost so much water it didn't even register as hot on the gauge.

 

To investigate the cause look closely at how the engine warms up:

 

heat felt from the heater

heat from the top hose

pressure felt squeezing the top hose, but no before there's heat.

 

No leakage from the pressure cap.

Brown staining or splash marks behind the fan suggest the water pump bearing.

 

You could consider flushing the system since you'll have lost your anti freeze anyway - always run with anti freeze for its corrosion inhibitor properties.

Keep an eye on water consumption by carefully topping up to the same level when cold.

Changing the oil is worth considering, especially if it smoked or smelled inside the rocker cover.



#11 gazza82

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Posted 10 August 2018 - 01:09 PM

Will be looking into this. Not sure what the thermostat does (total car nooby), but will have a look.

 

 

It opens when the water reaches a certain temperature in the engine to let cold water in from the radiator, etc. Then fluctates as the temperature goes up and down to try and maintain the level .. along with the cooling fan helping the air to flow over the rad.

 

If it sticks shut, you overheat and cook the engine, which can cause it seize or damage the soft bearing shells.  (this is usually what a failed Mini thermostat does!)

 

If it sticks open (or someone has removed it!), it struggles to maintain the right temperature and messes up your fuel consumption, and it can also cause condensation inside the engine which contaminates the oil .. looks like mayonnaise in the oil filler cap

 

 

Spend a bit of time reading up on the internet about how an engine works (especially an older one as the moderns are full of electronics!)



#12 luismx123

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Posted 10 August 2018 - 06:36 PM

 

Will be looking into this. Not sure what the thermostat does (total car nooby), but will have a look.

 

 

It opens when the water reaches a certain temperature in the engine to let cold water in from the radiator, etc. Then fluctates as the temperature goes up and down to try and maintain the level .. along with the cooling fan helping the air to flow over the rad.

 

If it sticks shut, you overheat and cook the engine, which can cause it seize or damage the soft bearing shells.  (this is usually what a failed Mini thermostat does!)

 

If it sticks open (or someone has removed it!), it struggles to maintain the right temperature and messes up your fuel consumption, and it can also cause condensation inside the engine which contaminates the oil .. looks like mayonnaise in the oil filler cap

 

 

Spend a bit of time reading up on the internet about how an engine works (especially an older one as the moderns are full of electronics!)

 

Cheers for that one! Spent a day reading up the bits a few days ago :) Just wondering if a summer/winter one is better... especially since im gonna be driving from march-nov here in austria where it can get fairly cool on both ends of the calendar. 

also checked my rad today. had to fill 0.5L in and still cant find any drips... wondering if there is just a bunch of air somewhere after the overheating.. hmmm... 



#13 cal844

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Posted 10 August 2018 - 06:39 PM


Will be looking into this. Not sure what the thermostat does (total car nooby), but will have a look.


It opens when the water reaches a certain temperature in the engine to let cold water in from the radiator, etc. Then fluctates as the temperature goes up and down to try and maintain the level .. along with the cooling fan helping the air to flow over the rad.

If it sticks shut, you overheat and cook the engine, which can cause it seize or damage the soft bearing shells. (this is usually what a failed Mini thermostat does!)

If it sticks open (or someone has removed it!), it struggles to maintain the right temperature and messes up your fuel consumption, and it can also cause condensation inside the engine which contaminates the oil .. looks like mayonnaise in the oil filler cap


Spend a bit of time reading up on the internet about how an engine works (especially an older one as the moderns are full of electronics!)
Cheers for that one! Spent a day reading up the bits a few days ago :) Just wondering if a summer/winter one is better... especially since im gonna be driving from march-nov here in austria where it can get fairly cool on both ends of the calendar.

also checked my rad today. had to fill 0.5L in and still cant find any drips... wondering if there is just a bunch of air somewhere after the overheating.. hmmm...

Check the bottom hose clips are tight!

We just fitted a new radiator to my estate, the bottom hose was pinched in the clip causing it to leak, along with a hairline fracture on the hose stub...

Minis!

#14 luismx123

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Posted 10 August 2018 - 06:44 PM

 

 

 

Will be looking into this. Not sure what the thermostat does (total car nooby), but will have a look.


It opens when the water reaches a certain temperature in the engine to let cold water in from the radiator, etc. Then fluctates as the temperature goes up and down to try and maintain the level .. along with the cooling fan helping the air to flow over the rad.

If it sticks shut, you overheat and cook the engine, which can cause it seize or damage the soft bearing shells. (this is usually what a failed Mini thermostat does!)

If it sticks open (or someone has removed it!), it struggles to maintain the right temperature and messes up your fuel consumption, and it can also cause condensation inside the engine which contaminates the oil .. looks like mayonnaise in the oil filler cap


Spend a bit of time reading up on the internet about how an engine works (especially an older one as the moderns are full of electronics!)
Cheers for that one! Spent a day reading up the bits a few days ago :) Just wondering if a summer/winter one is better... especially since im gonna be driving from march-nov here in austria where it can get fairly cool on both ends of the calendar.

also checked my rad today. had to fill 0.5L in and still cant find any drips... wondering if there is just a bunch of air somewhere after the overheating.. hmmm...

Check the bottom hose clips are tight!

We just fitted a new radiator to my estate, the bottom hose was pinched in the clip causing it to leak, along with a hairline fracture on the hose stub...

Minis!

 

gonna do that tomorrow. Getting a pair of ramps to lift Milo up and get a look from the bottom.  I got an MOT equivalent test end of August and just trying to keep my mini looking good and running sweet till then, and then once that passes - fingers crossed- im planning to get a new rad+pipes+thermo etc. Im just lost to where its going... no drips on the floor.... no "mayonnaise" white cream building inside the rockers.






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