Coolant flush question...

When I started working on vehicles (American made early 70's) a coolant flush was to install a tee in one of the heater hoses with a garden hose adapter, installing a radiator cap extension adapter and running the engine to operating temperature while the garden hose put water in and the adapter spewed water out.

Just curious, what exactly does flushing the coolant system mean to you?

(Today I carefully drain and capture the coolant and recycle in the monthly county recycling programs. I don't consider it flushing though just drain and fill.)

 

well, I think most folks remove the thermostat and run distilled water through the system until it comes out clear and then they put the thermostat back in and add the appropriate amount of coolant. If it is 50/50 mix already you'd probably wanna go ahead and drain and fill a few times.

I personally just open the petcock valve and let it drain and refill it back to spec. I do this every few years. I'm lazy.

 

I put a flush/fill kit on my 2008. It means hooking up the waterhose to the tee, cramming the split hose into the radiator cap (since the L shape thing is too big around to fit) so the water can come out on ground, turn water on, start truck, put on heater setting & let it run until all colored antifreeze is gone. Then turn truck off, water off, remove both hoses, put cap on tee, loosen drain on radiator and let water drain, close radiator drain, fill radiator with new coolant, start truck back up still on heater setting, keep pouring in coolant until radiator fills and won't take any more, put cap back on radiator. Top off overflow jug after running it and getting to operating temp and letting it cool back down. I use the 100% coolant because system incl motor holds over 2 gallons so I get the whole gallon of antifreeze in and top off with water.

 

I consider a cooling system flush to be when you add water after draining the system, and keep running water through the system until it drains clear. Flush fittings/adapters (tees) are helpful but not required for a flush. Some people use flushing chemicals as normal procedure in a system flush. I don't consider it necessary to use flushing chemicals, but I would use them on a neglected system to help remove sediment, rust and scale. But I don't use the flushing chemicals because I keep up on my vehicle maintenance... which is the reason I only do drain and fills (as you do). Haven't had an overheating problem in 28 years.

 

no chemicals either and i just prefer this to messing with drain on radiator much, it's a plastic resistant bitch. once and done is all i want with how it is. not crossthreaded or stripped either, just tight. thanks for heads up on the lisle kit. i just used one of the tee that was left from a kit for my car. adlibbed the hose just so it wasn't going inside eng bay.