Help needed, I have an ongoing problem with coolant loss. Every time I tow my caravan and make the engine work fairly hard I get the ''coolant low'' light come on. I top up (about 1/2 litre) and motor on. If I drive carefully and keep the speed down it does't happen.
I drive to work (50 mls round trip) every day, motorway the whole way and get no coolant problems - it only happens when towing. Checked for external leaks, found nothing. Is it likely to be the gasket just starting to go? Performance seems slightly down but difficult to gauge. (2.2 GTX Hdi).
I'm not sure of any inherant problem, as you're towing when it happens then I'd think the extra strain is making your engine hotter and maybe it's blowing past the spring in the cap.
You could have both system and cap pressure tested, maybe it's worth getting a new cap anyway as I don't think it'll be too expensive (famous last words...).
Or, as my dad would say, ignore the problem until it manifests itself in a more apparent manner...
Keep your eye on the level, watch the temperature gauge.
I have had a pressure test carried out by the local stealers (for free). they said that there was a pressure drop, from 1.4 Bar down to 1.1 Bar and therefore suspected an internal leak. However they wanted money before they would investigate further. I am therefore left with second guessing the problem. It is possible that the heater matrix is leaking, however there is no apparent sign or smell. All I am left with (apart from trying a new filler cap), is to presume the gasket is starting to go.
Looking at past posts on head gasket failure, it looks like a doomsday scenario involving a replacement engine at worse. Hence my worry that it may be best to get the head looked at before doomsday!
Help needed, I have an ongoing problem with coolant loss. Every time I tow my caravan and make the engine work fairly hard I get the ''coolant low'' light come on. I top up (about 1/2 litre) and motor on. If I drive carefully and keep the speed down it does't happen.
I have had a pressure test carried out by the local stealers (for free). they said that there was a pressure drop, from 1.4 Bar down to 1.1 Bar and therefore suspected an internal leak. However they wanted money before they would investigate further. I am therefore left with second guessing the problem. It is possible that the heater matrix is leaking, however there is no apparent sign or smell. All I am left with (apart from trying a new filler cap), is to presume the gasket is starting to go. 
Thanks for that James, I'll give it a try. 