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Old 22-12-2021
sabSK  sabSK is offline
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Quote:
Originally Posted by layback40 View Post
Over 2 XJ diesels I have never replaced one. As they have alloy heads, the heads corrode away first.
The biggest issue you will have if its been run with tap water for a long time is precipitation of aluminum hydroxide in the radiator. The red color you see in the water is not conventional rust. Its Aluminum hydroxide. It is less soluble in cooler water so as the water cools in the radiator, it forms scale in the core.
Lowering the PH by adding vinegar will help dissolve it. Citric acid is often used. I have heard of flushing the radiator with steam/boiling water as well. Inhibited sulfamic is a common cooling system cleaner. Many flushing additives are based on it.
I now run my cooling system with corrosion inhibited water and without pressure. Works well. probably if I pressurized it there would be leaks in the radiator everywhere. The system I have set up looks a bit agricultural.
Probably not a good idea in cold climates though.
Thanks for the excellent explanation. If the radiator is the only concern, I can live with that because I might need to replace it anyway. I was mostly worried about the freeze plugs and cylinder liners because I saw somewhere that they can leak from the lower seal (if I remember correct) because of excessive corrosion. Your setup is opening some other options for me. Might dig into that as well. Anyway, I will give it a flush in general for the whole system and hopefully only the radiator might need changed (cracked on the top, plastic part)