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remove thermostat when flushing w123 diesel cooling system

I don't know if I am reading the MB manuals correctly, but it seems to me that in the topic (20-015) on cleaning the cooling system (deoiling and decalcification/derusting) they say to remove the thermostat when performing this. Is that correct? What is the reason? I can't imagine the t-stat being damaged by a bit of cleaner. If it is neccessary to remove the thermostat then what do you do--reassemble its housing without it before doing the flushing? I am assuming you have to leave the seal in?

Oh, and what kind of place sells citric acid? (for the decalcification)

This is all for a 1980 300 non-turbo diesel (W123 with a 617.912 engine).

George

Reply to
george
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Calcification is pretty rare if the coolant is MB coolant and regularly changed... Pep Boys and alike should have citric acid cooling system flush.

Thermostat removal is a must or whatever you pour into the cooling system will not circulate to the radiator... only the engine if it ever gets there... so by removing the thermostat, you allow the whole system to circulate regarless of engine temperature.

Reply to
Tiger

Ditto (for the t-stat removal).

Whether the seal is put on during flushing does not make much difference. The seal isn't very tight without t-stat anyway. Also, flushing is only a short period. There will be some dripping.

If I remember correctly, the MB manual menti> Calcification is pretty rare if the coolant is MB coolant and regularly

Reply to
Wan-ning Tan

the problem is i don't know exactly what's inside--this is a used car and on top of that i just installed a second-hand radiator. i thought it can't hurt. i don't really see any signs of calcification but i do see some rust and the citric acid flush is for derusting, not just decalcification.

got it. thanks!

"neutral or mildly alkaline cleaner" for deoiling. "citric, tartaric or oxalic acid" for decalcification and derusting.

Reply to
george

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