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Showing results for tags 'radiator coolant pressure'.
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Hi all I’m having problems with my 1999 Td5 Disco’s cooling system which I can’t seem to fix, (or diagnose correctly for that matter) The symptoms include a build up of excess pressure that causes the top hose to swell and become very hard and not easy to squeeze at all. Even after being left overnight to fully cool, most of the pressure is still there. Not only that, but the pressure causes the coolant in the expansion tank to disappear until the cap is released, at which point the coolant appears to rise from the depths to nearly where it should be. While under the highest pressure a little coolant is forced from the radiator lower hose junction despite being tightly done up with a jubilee clip. (there’s a LOT of Pressure built up to be sure) The top hose gets nice and hot as it should do, but the radiator itself stays cold all over, so it seems obvious that the coolant isn’t circulating as it should. The lower hose and thermostat don’t get hot either. Heater works fine, the temp gauge sits bang in the middle where it should be once it’s warmed up, though I think it does seem to be taking a little longer than usual to get warm, but that could just be the colder weather that we’ve been having over the last week or so. I’ve replaced the coolant pump, the thermostat and the expansion tank cap already. There’s no oil in the coolant and there’s no creamy gunk in the rocker cover either. Looking in the expansion tank with the engine running there’s no coolant being forced up from below as far as I can tell, the only bubbles in there seem to be a result of the coolant being pumped back into the tank via the small tube that comes from the top of the radiator The only other thing of note is that on removing the radiator to flush it through I saw a wet rusty/muddy patch just on the weld where the two metal pipes, (the coolant rail?) are joined side by side just below the radiator, I gave it a light scrape to clean and coolant started to run in a thin stream from a small hole. Not sure if it was leaking a little bit from there already but it could have been but at a much slower rate than before I’m at a complete loss as to what’s going on here, worried that it’s a cracked head or head gasket but no oil in water, no water in oil, runs fine, no smoke black or white from exhaust. Anybody had this same combination of symptoms? Excess pressure, coolant forced from expansion tank, only to quickly return when cap removed and cold radiator when temp gauge shows normal and top hose hot ‘n’ swollen? Any help or ideas please