jim21070 2 Posted October 3, 2006 On Sunday my heater matrix sprang a leak and soaked the drivers footwell. It was less than two years and 10,000 miles old. It replaced a blocked matrix. I received my new one from GSF and fitted it today. The new Valeo matrix came with a service bulletin explaining that premature failure was possible if the cooling system contained any corrosive deposits. It went on to say that unless the cooling system was fully flushed and treated to a "conditioner" failure within 9 months was a distinct possibility. The most likely point of failure would be on the "U" bends at the end. My cooling system is spotlessly clean and indeed has had a recent change of coolant when I did the water pump and cambelt. On that occasion the old coolant ran out a nice clear blue colour and today it is the same. Intrigued, I investigated where the old matrix failed and lo and behold, it had a pinhole right on the tightest point of one of the "U" bends. I attacked it with a junior hacksaw and it appeared that the point of failure was on a very thin portion of the tube where it looked to have been kinked slightly during the bending process during manufacture. The tubes were clean and there was no sign of any corrosion. I did notice however that the inside of the matrix tubes and the two aluminium water pipes was coted with a very thin layer of a hard, dark brown substance that looked like limescale (rock). We are in a very hard water area here. The old matrix was not a Valeo but some aftermarket one I'd never heard of. Had it not been for the bulletin, I would have put the failure down to a manufacturing defect and left it at that. Now I'm pondering the following: What has caused the limescale build-up (albeit very thin) given that the cooling system never needed topping up between yearly changes and a 50% antifreeze mix is always present? Has anyone else experienced this? A search reveals nothing. Should any sort of "conditioner" be added and if so, any suggestions? Any other suggestions to make sure my new matrix does not go the same way Would distilled water be a good idea in the cooling system? Does anyone else do this? Any thoughts on the failure in general? Share this post Link to post Share on other sites
welshpug 1,657 Posted October 3, 2006 very odd for it to fail that quickly, but it may be your water as yopu mentioned, especially if its very "hard" try running an antifreeze mix i.e readymixed, to eliminate the need to add water. or just fill up with 100% coolant Share this post Link to post Share on other sites
Mongo 0 Posted October 3, 2006 very odd for it to fail that quickly, but it may be your water as yopu mentioned, especially if its very "hard" try running an antifreeze mix i.e readymixed, to eliminate the need to add water. or just fill up with 100% coolant 100% coolant is not recommended,so i wouldn't do that. If you think theres a problem with your water, boil it in a kettle first and then put it in a container to cool. Or buy de-ionized water and mix it with the anti freeze 50/50 which is the recommended mix. Share this post Link to post Share on other sites
Beastie 1 Posted October 3, 2006 This happened to me once when I was stupid enough to buy a non genuine coolant bottle cap from a motor factor. One hot summer the relief valve in the cap stuck solid and the system over pressured. The heater matrix seemed to be the weakest link. Share this post Link to post Share on other sites
Guest BrainFluid Posted October 4, 2006 (edited) Distilled water is a very good idea. Its pure water afterall! I was reading somewhere, sorry I cant remember where, about an old man who for years did it the old fasioned way and only ever used distilled water with a eggcup full of some kind of oil added for his coolant. Apparantly he never had a problem, lol, much to his motor factors dismay EDIT: Obviously I'm not saying that you should 'just' use distilled water, mix it with some antifreeze of course. Edited October 4, 2006 by BrainFluid Share this post Link to post Share on other sites
Beastie 1 Posted October 4, 2006 Boiling water only gets rid of "temporary hardness" caused by Calcium and Magnesium Bicarbonates. Permanent hardness is caused by Chlorides, Nitrates and Sulphides of Calcium and Magnesium. Boiling has no effect on permanent hardness of water. If the water in your area is drawn from boreholes down to the chalk substrata below the water table then you are going to get seriously hard water (average in UK is 13.2 degrees Clarke) Distilled water contains no minerals - and it's desperate to get hold of some. The aluminium in your engine will do very nicely so the distilled water will eat it away very happily. De Ionised water or rain water collected in a plastic container (providing you don't live near a fossil fuel power station) is a good solution. Cheap antifreeze contains glycerin and is a poor solution. A premix such as Forlife is an excellent solution if your budget runs to it! Share this post Link to post Share on other sites
Guest BrainFluid Posted October 4, 2006 Distilled water contains no minerals - and it's desperate to get hold of some. The aluminium in your engine will do very nicely so the distilled water will eat it away very happily. De Ionised water or rain water is a good solution. I stand corrected Why does De ionised water not do that? Share this post Link to post Share on other sites
