50 replies to this topic

[M0U5EY]

Its more likely that the head is cracked rather than the block

 

As it had been over-heated the head should have been pressure tested, do you know if it was ?

 

It could also be a stuck thermostat which is a simple fix, was it renewed ?

Don't think the head is cracked as that was skimmed and I would be amazed if it wasn't checked over by both the mechanic and the skimmers... I believe it was pressure tested on the day by the AA and don't remember it being a big issue, maybe a small loss but that was most likely down to the warped head which was skimmed... As for the thermostat, think that is fine, fan comes on as it should. Will be sent to someone who knows what they're talking about!

[Itsaminithing]

.... it boils over while the thermostat is still reading half temp which is normal for the car.....

it might be normal for your car -but that's not normal for an MPI.

 

When you take the car in to get it checked out make sure to mention this to them.

It's no good them just fixing the problems that overheating has done, they need to find the root cause of your overheating problem.

After that it should provide reliable transport given regular maintenance (or at least as reliable as a classic car can be), the biggest issue will be keeping the rust at bay -but that's an issue for another day.

 Mini specialists might charge more per hour than a general mechanic but a good one should find any issues fairly quickly.... & it should work out cheaper than changing parts in the hope that it might get the car working properly. Good Luck.

[Retroman]

I am sure they checked the head over, perhaps ask them if it was crack / pressure tested at the machine shop ?

 

A road side pressure test may not show a cracked head,

 

When an engine is seriously hot a hairline crack is all it takes, heat moves metal and with full combustion pressure it can be invisible to the naked eye

 

If the fan is coming in that means it's overheating which is a symptom of a stuck thermostat

 

The thermostatic fan switch is switches the fan on when its hot. I mean the the thermostat in the housing on the head

[M0U5EY]

Ok, I will relay this all to the next place it goes to, thanks for the help. Just to clarify, the temp guage goes to the black line on the guage (about 1/3-1/2 way up it) and always has done, is this not normal?

[M0U5EY]

Ok, I will relay this all to the next place it goes to, thanks for the help. Just to clarify, the temp guage goes to the black line on the guage (about 1/3-1/2 way up it) and always has done, is this not normal?

[russo]

Correct diagnosis is the key here. It really is worth spending the money and getting correctly diagnosed as it may be something simple. Ive seen it so many times where people replace the engine when it could have been solved cheaply with correct diagnosis.

[Retroman]

The gauge going 1/2 way may be normal, but not for when its hot, if the fan is kicking in its hot and the gauge should reflect that.

 

Rosso is really right in what he is saying...I once took a Honda engine out of a Rover 216 GSI, it was seized solid could not turn it with a big bar...all geared up for a rebuild, several hours to unhook all the wiring/ pipes/ driveshafts etc and lift the lump out. The car was low mileage and had been on its roof, engine seized solid, presumably ran dry of oil whilst upside down. 

   Turned out to be the alternator !!

Assume nothing, diagnosis is key, best of luck

[M0U5EY]

Ok, managed to get some more info as follows;

• Drove it for about 20 mins and was holding its fluid
• All 3 hoses around thermostat are hot, hinting to the thermostat working fine
• The radiator is hot all over indicating no radiator issues
• The main hose in front of the rocker cover is getting slightly pressurized after a drive
• Fluid is boiling in the expansion tank
• The fan is coming on fine around the black line on the gauge 

My next action is to take the thermostat out and try and run it without that to see if that stops it pressurizing etc and to put a hose pipe into the top pipe and hopefully watch it flow through the system indicating no blockage, how does that sound?

[Merryck]

How old is the radiator? Is it definitely good?

 

Are you getting hot air through with the heater?

 

I'm not leading anywhere with this, I just know these things are connected and trying to reveal the whole situation to give others a better chance of helping!

[M0U5EY]

Radiator most likely came with the car, haven't seen anything indicating otherwise... As for the heating, it is indeed working and was one of the tests the RAC guy did when it first happened, it also causes the expansion tank to bubble up indicating its flowing fine.

[Bat]

Hi,

First, common fault on MPIs is the cap on the expansion tank. Replace this with a new genuine/good quality one.

Second while you're there what colour is the coolant?

Any sign of it being brown means it needs a really good flush. This also seems common on MPIs.

Cheers 

[M0U5EY]

Hiya, thanks for that, thats probably a good think to do in the near future but looks ok now.... Fluid is merky brown but have just run a hose pipe round it and is now flowing clear although still a little brown in the expansion tank (stained inside of tank maybe). Quick question, when up to temperature, if I turn off the car and take the cap off the tank should it make a fuss and squirt water or should it just come off? Thanks!

[M0U5EY]

Ok sitrep, system flushed and re-filled, thermostat removed. Idled for about 5-10 mins by which time the fluid was boiling very well in the expansion tank, guage read at the black line and fan just came on, any ideas?

[M0U5EY]

Another update, water pump appears to be working fine (took hose off and ran engine for 5 seconds and was flowing fine)

[DeadSquare]

Ok sitrep, system flushed and re-filled, thermostat removed. Idled for about 5-10 mins by which time the fluid was boiling very well in the expansion tank, guage read at the black line and fan just came on, any ideas?

 

1)   If there is a "hole" through which enough water water is escaping for the engine to boil, you must surely be able see what has come out and also notice the level falling in the radiator.

 

2)   If there is a "hole" between the combustion chambers and the cooling system, you should be able to see bubbles in the radiator.

 

3)   Is the fan rotating the the correct direction to expel air into the nearside wing ?