I recently bought a used engine from a Japanese half-cut. It's in great condition, except that it seems to have been left long-term with just a trace of coolant/water in, and the inside of the coolant passages is rusty. I have flushed out a lot of rust sludge with a hose, but I am still concened that the degree of rust will compromise heat transfer from the engine to the coolant. Plus I just don't like it being there. The block has what I would consider a resonable degree of rust (dry, yellow-brown iron oxide) and does not concern me too much, but the head seems to be rustier, with a dark, hydrated iron oxide look.
The engine is partially stripped, all the oil-filled components are still on (so no problem to get wet externally, things like fuel injection pump, vacuum pump (it's a diesel), are properly blanked off. I plan to make blanking plates for the water pump coolant passages and pour in some sort of acid via the thermostat housing opening in the head, then later drain it out at the drain cock and flush.
Where I live, it's not easy to get hold of industrial chemicals. Ideally I would use phosphoric or oxalic acid, but no chance to get those here. I can get large quantities of vinegar though.
Apart from the awful smell, is there any reason not to use vinegar/acetic acid to clean out the rust? I would flush with an alkali (bicarbonate of soda, a weak lye solution or sodium hydroxide) afterwards to remove residual acid.
The only other thing I know I could get hold of would be cola, but I know that would be too weak. Possibly I could find citric acid, but I don't think that will do much for anything but light surface rust.
All core plugs will be replaced of course, but after treatment.
Thanks
The engine is partially stripped, all the oil-filled components are still on (so no problem to get wet externally, things like fuel injection pump, vacuum pump (it's a diesel), are properly blanked off. I plan to make blanking plates for the water pump coolant passages and pour in some sort of acid via the thermostat housing opening in the head, then later drain it out at the drain cock and flush.
Where I live, it's not easy to get hold of industrial chemicals. Ideally I would use phosphoric or oxalic acid, but no chance to get those here. I can get large quantities of vinegar though.
Apart from the awful smell, is there any reason not to use vinegar/acetic acid to clean out the rust? I would flush with an alkali (bicarbonate of soda, a weak lye solution or sodium hydroxide) afterwards to remove residual acid.
The only other thing I know I could get hold of would be cola, but I know that would be too weak. Possibly I could find citric acid, but I don't think that will do much for anything but light surface rust.
All core plugs will be replaced of course, but after treatment.
Thanks
