Possible 1.8 cooling problem solution

[Kearton]

Speaking to a friend who has had several kit cars, including a GTM Libra with a 2.5 V6. When he heard about the head gasket problems he asked about it in the owners' club. The solution recommended was to drill a small hole in the thermostat.

Apparently the thinking is that thermal shock is the cause of gasket failure:- the engine heats up, the thermostat opens then the cold mass causes it to shut again. Since the engine is already up to temperature it then gets hotter causing the problem. Drilling the hole allows some hot water out before it opens, reducing the pressure in the engine and raising the temperature slightly in the external coolant so reducing the thermal shock effect.

Whether or not that explanation is correct, the modification seemed to work as no problems occurred afterwards, even with hard use.

I can ask him for more details (e.g. hole size & position) if people are interested.

Regards,
Kearton

[Poppy]

Originally Posted by Kearton

Speaking to a friend who has had several kit cars, including a GTM Libra with a 2.5 V6. When he heard about the head gasket problems he asked about it in the owners' club. The solution recommended was to drill a small hole in the thermostat.

Apparently the thinking is that thermal shock is the cause of gasket failure:- the engine heats up, the thermostat opens then the cold mass causes it to shut again. Since the engine is already up to temperature it then gets hotter causing the problem. Drilling the hole allows some hot water out before it opens, reducing the pressure in the engine and raising the temperature slightly in the external coolant so reducing the thermal shock effect.

Whether or not that explanation is correct, the modification seemed to work as no problems occurred afterwards, even with hard use.

I can ask him for more details (e.g. hole size & position) if people are interested.

Regards,
Kearton

Hi. I believe that the main cause of h/ g failure is because of loss of coolant.....How else would an engine over heat.? There is a solution to that problem in the way of a coolant sensor....... If you look up what every k series needs, you will find it. Poppy

[craig8661]

i had a rover 1.4 and could not kill it i belive too water loss is what causes the head gasket to go to over heateing.

i have a 75 at the min was boiled dry at least 5 times as im scrapping the engine found it was a dodgy hose and it still is running now it is showing sighns of head gasket falior now but it still keeps running

[James.uk]

It's worth bearing in mind that when a head gasket starts to leak you lose water anyway.. It can be a "chicken or the egg" situation innit...

Head gaskets can start to leak because of a faulty gasket, faulty head bolt, wrongly tightened bolts, dodgy casting etc etc...
...

[dissy1810]

The prt thermostat was fitted to later model cars as a solution to thermal shock

[chrissyboy]

Originally Posted by Kearton

Speaking to a friend who has had several kit cars, including a GTM Libra with a 2.5 V6. When he heard about the head gasket problems he asked about it in the owners' club. The solution recommended was to drill a small hole in the thermostat.

Apparently the thinking is that thermal shock is the cause of gasket failure:- the engine heats up, the thermostat opens then the cold mass causes it to shut again. Since the engine is already up to temperature it then gets hotter causing the problem. Drilling the hole allows some hot water out before it opens, reducing the pressure in the engine and raising the temperature slightly in the external coolant so reducing the thermal shock effect.

Whether or not that explanation is correct, the modification seemed to work as no problems occurred afterwards, even with hard use.

I can ask him for more details (e.g. hole size & position) if people are interested.

Regards,
Kearton

nothing to do with it .. drilling a hole in the stat its only purpose it to allow any air bubble that gets trap under the stat to pass through ... hgf is causd by coolant lose ,which leads to the water pump playing up thus losing the circulation of coolant to cool the engine ,pressure build up temp getting higher which in turns creates hot spot to the head and the gasket lifting ... your mates car just had air in the system ,with a hole in the stat the air escapes and the coolant can circulate ...some stats are made with holes in as certain cars are prone to air pockets when filling the system ,