Hi David, that is very strange, where is the coolant going??? i had a very simmilar problem on a company 2.3l Ford Granada many years ago, it was eventually found (after the engine blew a core plug) that the head was cracked between an exhaust valve and a waterway causing the water system to become over pressurised and blowing the coolant out of the header tank cap. perhaps a call to Russell Walsh of MG Rover solutions may throw some light on the problem, because he has seen so many head failures for whatever reason. i thing everyone will be interested in the outcome. Kind regards Bryan
Have you replaced the rad at all David? Meg's last leak after HG replacement by Russell turned out to be a very weepy rad! It was boiling off before dripping so wasn't noticeable.. but she let water out in a similar fashion to yours.
Checked under the carpets?
I installed one of the first B&G low coolant kits. I never conected the warning light as I did not want to put extra holes in the centre consol and even at racing speed with helmet the alarm can be heard. Within a week of fitting it had paid for it's self, I had been doing a lot of stop start motoring that morning, about lunch time I started the car and the beeper sounded checked the water level..empty. Filled it up then went on the 15km drive to the workshop, just as I arrived it started to beep, the temp gauge all this time showing normal. Checked the water level, none. Left it at the workshop and waited for the bad news, phone call the next morning come and pick up car. As it had only been there for a few hours before they closed knew it wasnt a HGF. Water pump less than 20000km, 12 months old had failed.
Hi David ~ Me again, one of the HGF failures sorted by the MG Owners Club was as the result of the impellor coming off the pump inside allowing the water to boil off, i beleive that Moto-Build do a better water pump with a brass impellor but they are around £60, whereas the replacement X part one is £30. Have you checked the underfloor pipes as theese are bad for rusting through and weeping out, the stainless ones at £60 are good value and seems sensible to replace them whilst the system is drained. Regards Bryan