Frax Posted May 1, 2013 Share Posted May 1, 2013 Hi all. I have been running my 300tdi for over a year now and the coolant level never stays anything like full. When I top up the expansion tank to about 1/2 way and go for a drive I loose coolant level, the expansion tank will almost empty with only about 1/2" left in the tank showing. I can drive like this for weeks and the level never changes - It runs at normal temp and has never overheated. Topped it up this morning and went for a drive, just to get home to find steam coming from under the bonet, had a look and the level of coolant had dropped to its usual place. I have the white expansion tank fitted so easy to see the level. Do you think the cap is faulty or are they all like this. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted May 1, 2013 Share Posted May 1, 2013 Where was the steam coming from? My parents Audi does this due to a weeping radiator. If you fill it up, it leaks down to the minimum line over a few weeks. If you leave it at the minimum line, it doesnt seem to drop any further. I recon that when its full, the system pressurises a lot more, which helps the water seep out the old radiator. When at minimum, the larger volume of air in the expansion tank means system pressure at operating temperature is lower, and thus it doesnt leak. Quote Link to comment Share on other sites More sharing options...
Frax Posted May 1, 2013 Author Share Posted May 1, 2013 May try some rad weld in it and see what happens, I will do no harm to try. Quote Link to comment Share on other sites More sharing options...
Frax Posted May 3, 2013 Author Share Posted May 3, 2013 Found where the leak is coming from, The black plastic plug on top of the radiator - for some reason the top of the plug has split and parted with the threads --------- does anyone know where I can get one of these. Are they anything special of will any plug do the job. It's OK found some, plastic and brass what should I get ? Quote Link to comment Share on other sites More sharing options...
western Posted May 3, 2013 Share Posted May 3, 2013 one from simonR X-eng nice alloy plugs,http://www.x-eng.co.uk/StoreDisplay.asp?SL=45&MID=79 use the link in his sig Quote Link to comment Share on other sites More sharing options...
Frax Posted May 3, 2013 Author Share Posted May 3, 2013 Nice - I like Si's stuff Quote Link to comment Share on other sites More sharing options...
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