Jeep XJ 2.5td freeze plugs.

[sabSK]

Hi. I did a quick search on the forum but couldn't find any info on the VM freeze plugs. Has anyone changed them at all? If so, is it easy or recommended as a preventive maintenance?
My concern is with my newly bought wj 3.1td but I am posting here since the 3.1diesel isn't popular on this forum (didnt know that) and it shares similarities with the 2.5td xj. The PO has the cooling system filled with water and I don't know how long it has been like that for. I am planning for a flush with vinegar but I am worried I might disturbed said plugs or perhaps to replace them for a peace of mind. Difference between the xj(8plugs) and wj(20 plugs) is that the wj has quite a few more(12) and I have no idea how to take them out or even where they're located. But at this point is more of a research topic for me so I will try to source a repair manual for the specifics.
I am familiar with the diesel xj too because my brother has one (the inspiration truck for my wj) and I love the little tough guy when I drive it. I hope I will like the wj just as much. Is there any other name these plugs go by, maybe thats why i can't find info.
Thanks in advance!

[layback40]

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.

[LuluBelle]

Flush it with Liquid Intelligence 239 This stuff really works you should of seen the gunk that came out both my xj's (petrol)

[sabSK]

Originally Posted by layback40

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)

[sabSK]

Originally Posted by LuluBelle

Flush it with Liquid Intelligence 239 This stuff really works you should of seen the gunk that came out both my xj's (petrol)

That seems to have good reviews but a bit on the expensive side for me. I live in Europe so will check what is available here. One thing is for sure, i definitely need to perform a good flush (or two )
Cheers