Thread: disco overheated but temp guage stayed at half????

Has it got any leaks? The temp sender will only work if it covered in liquid. If the coolant level drops below the temp sender the guage will not work.

I had the same problem years ago, and it cost me an engine. If it reaches halfway one can assume it is overheating. Mine overheated for another five years even with a low mileage used engine. I fitted a VDO temp gauge and several different radiators to no avail. I even put another radiator cap on the blind side of the radiator, so I could clean it out better. Nothing made any difference until I was sitting under a tree at Burra one day waiting for it to cool down, and decided to get out and pull the insulation off the inside of the engine bonnet and place it in a bin nearby. The effect was that now the engine refuses to get over ninety degrees, even on a hot day with the aircon going. Problem solvered. I think that if you turn the aircon up to flatout cold, then the compressor will run constantly, whereas if you turn it back a little bit, it will cycle, allowing everything to cool down a bit. I also fitted an intercooler with larger core, and after a while on the dyno the horsepower was almost doubled. It runs a bit rich and blows smoke when started, but the difference is incredible. The intercooler cost six hundred bucks, and the dyno two hundred for two hours, including remove and replace front tailshaft. Fuel consumption is down two or three miles per gallon, but the difference is incredible. If you want, I can send you a scanned copy of the dyno graph. The tuning work was done at Blackwood Dyno in Adelaide. The chap that runs it is Ricky Monsarrat and he runs a six second funny car at the drags. He does a lot of Pommy cars, and has achieved a 90Kw increase on one of those big Ford F250 utes.
Cheers and hope this helps u... Dennis in Broken Hill

check the cap again, mine did this and a new cap fixed the problem. If the radiator has recently been done their might be an air lock in the system. Have you gotten it up to running temp and run the heater to make sure the water is circulating throughout the whole system?