Coolant flush / shavings ????

[BR3W CITY]

solidaxl What do you mean? To flush everything out? (for changing out for water, I just meant a quick hose-flushing).

FWIW I've had situations where I've had a sitting vehicle develop gelled coolant, or have so much corrosion in the passages that I felt it needed to be flushed out with some force.

a. How much force you need to use will alter the method. Radiators and heater cores will stand up fine to the ol' garden hose, so long as there isn't a total blockage causing pressure to backup (risks thin coil areas on radiators/heat exchangers).

b. If you have a blocked radiator or heat exchanger, pressure beyond the hose isn't a good idea, so you'll have to try a chemical cleaner. These can be hard to get into the small internal passages. Sometimes you have to evaluate the situation, and consider when to replace.

c. If you rad's are fine, but the block/engine water jacket is crummy, then its just a little more work. You can pop the radiator hoses off, taking the radiator and heater out of the loop. Then pop out the thermostat or whole water pump; if your stuff is that badly gelled, the t-stat is probably gunk'd up and worth replacing. Having the pump off lets you check its condition, makes getting at the t-stat easier, and takes a potential blockage out of the flush. You can put the pump back on temporarily with the stat out, or leave it off and just start your flush one side at a time. Then back to the hose! You should be able to force out gunk and buildup pretty easily.

d. If you get blockages cleaned out but still want to clean the water jacket more or still have partial buildup, you can feed chemicals through it beer-bong low pressure style, and flush back out when ready.

Thats like the 50-year old coolant flush on, and you shouldn't "need" to go that far unless its reallly nasty. Don't do more than you have to, and be careful on the radiators if they are old, as the chance for leaks is pretty high if they are damaged at all.