Not entirely accurate and the kind of information that mis-informed press sprout tbh.
The K series when it first appeared was a brilliant power unit. It made more power and torque for its weight and fuel economy than any other engine on the market. In the original 1.4L capacity it was completely bomb proof. It would do 200K miles with a HG problem.
It was only after the capacity increase in 1994 that HG problems starting. There are a number of reasons for this happening. First off the thermostat is in the return from the radiator. This gives a delayed opening, not a problem for the cooler running 1.4 in a light vehicle, but it's bad news for the 1.6 and worse so on the 1.8, especially in the heavy Freelander. The PRT thermostat introduced in 2002/3 effectively controlled engine temperature, especially on the initial opening cycle. The cooling system isn't small, in fact the reverse is true. The radiator is to large, over cooling the coolant, closing the thermostat early.
Next the HG design was less than ideal. Rover or (PTP) used the elasopolyler gasket to ensure good sealing on the production line and through subsequent warranty period. The gasket was made badly, including the fire rings being upside down. De-lamination of the elasto took place at around 5 years or about 60K miles. Additionally the head used to be located with plastic dowels. This allows head shimmy on the block, resulting in the gasket's upside down fire rings eroding the head material and loosing clamping load.
So to cure the problem, the latest Payen blue elasopolyler with the steel dowels needs fitting along with the PRT thermostat. This will fix the K HG issues for the remainder of the useful life of the engine.
Rover weren't the only manufacturer to have engine problems. Peugeot 16 valve engines pop HGs before 100K and had large numbers of rod failures on there deisels. Vauxhall's Astra B&C 16 valve unit used to do HGs and timing belt tensioners regularly. Renault 1.9L diesel engines suffer piston failure at around 90K miles. The D3 TDV6 suffers random mileage crank failure rendering the engine as scrap and giving the owner a bill of £5K plus for a replacement engine. The same engine between 2006 and 2008 also had faulty oil pumps, scrapping the engine shortly after the belts were changed.
The list of engine failures is long and many of them cost much more to fix than the humble K series.
For the record, the only K series power vehicle I now own is my MGF, which I did the HG on.
I have had many K powered vehicles, including 5 Freelanders. Only 2 K powered vehicles I've owned have had HGF. One was my wife's 98 VVC coupe and the other was my VVC MGF.
I have spent many years repairing all manner of cars, both in the workshop and at the side of the road. Trust me, the K isn't the worst out there.
It still is a great engine that was badly publisized in the media.
It can be fixed and for pocket money compared to other vehicles out there.