renewed on my diesel car last year and found the reservoir empty when I got home - the techy just hadn't run the engine enough for the thermostat to open fully. IIRC, the OP did not tell us the reasons for the water pump replacement, referring only to a coolant leak, but the reservoir blowing was said to follow-on from it, So I've recently had a coolant leak repaired on my 2008 model Ford fiesta where the mechanic noted that the water pump and thermostat needed replacing. Having had those replaced and my car returned to me, the leak has stopped however the coolant has begun to boil/bubble after driving the ~30 minute journey to/from work (~20 miles each way). Make sure your engine is off and cool, the vehicle is in Park or Neutral, and the parking brake is set. Coolant also helps keep your engine working as efficiently as possible, helps keep its emissions low, and even helps provide that toasty heater air on cold days.

I did, however, realise that there are sometimes no bleed points, because I think that's all I've ever had on any of my cars. Can't remember it being a problem before. Your car’s heating and cooling systems are important factors in having a comfortable ride all year round, but especially in extremely hot or cold conditions. Car Cooling System I have a couple of fridge compressors that I could try, but I'm getting used to the boiling method so I probably won't bother.. The puzzling aspect is the leak stopper suggestion. AFAIK there's no leak stopper to seal from within the combustion chamber (There are goos that are supposed to restore some compression but I THINK they are supposed to seal the rings). I try and be as cynical about garages as the next man, (though/so/because I have hardly ever used them apart from MOT's) BUT I think the innocent-until-serious-grounds-for-suspicion principle ought to be applied.The leak has definitely been repaired and despite the coolant bubbling after every trip to/from work, it doesn't look to have decreased in volume in the reservoir. The running temp (on the dashboard at least) seems to be normal, the only thing that's changed is that the fan boots in a lot sooner than it ever had done beforehand (I don't really expect it to have to come on for a 25 minute drive on residential roads). One thing I have noticed is that the fan doesn't seem to come on if I run the heater inside the car. Not entirely sure why this is, but in all honesty I know next to nothing about the internal workings of cars, hence why I went to a mechanic in the first place!

Perfect. Thanks for the advise. Have just been outside and managed to pull the little git straight out with a pair of long nose pliers as you say 👍. Can't believe how tight it was but so happy to of got it sorted. Thanks again 👍Clarkson cut holes in his classic Range Rover bonnet on the Bolivia Special to ameliorate an overheating problem, but that would affect resale. Less permanently you could remove the whole bonnet, but I donno how legal that would be in the famously anal UK. Well, you can buy stuff for head gasket failures. Some of them have copper (powder?) in them, which I'd guess is an inert-ish particulate filler. Active ingredient seems claimed as sodium silicate here.

In the winter, engines need to be stopped from freezing up and causing irreparable damage. You may need a replacement car cooling fan, car radiator, expansion tank, or intercooler, and at Halfords we’ve got it all. Car Air Conditioning unclip the two upper hoses by hand, unclip tank from the holding plates, drain in jar through the openings where you unclipped the houses, use the pliers to unclamp the main hose, pull the tank away from the hose. Install the new tank. If it were mine I would keep a close eye on the coolant. Your engine will only overheat if you loose a significant amount

If there was no overheating, the water pump replacement is a bit suspect, but is unlikely to have caused a head gasket failure, which seems to be suspected by the OP. The most obvious valid reason for replacing a water pump would be an overheating incident due to actual or suspected water pump failure . I suppose I could mist water into the air intake to slightly reduce the risk but there's a bit too much happening as it is. The mechanic I used took another look at it today and has returned it to me stating that it is in fact a problem with the head, stating he ran some tests and found gas to be escaping and entering the coolant system. He has now offered a short term solution by saying he can apply some sort of leak repair stuff which requires the coolant system to be flushed then the additive put in with new coolant. Does anybody have any experience with this and if so, how long is it likely to withhold? My car is due to have it's MOT in February, how likely is it to pass this?