Can't seem to dial up what must be a dozen old threads, sorry.
First coolant change coming up on Ford 3.7L. I could have sworn that Ford didn't like flush--only drain. Can't find it in the manual though.
What say you? Drain or flush and drain?
Drain the radiator, and use the Lisle funnel when refilling
There is no need to flush it unless you went like 300k without ever changing it and it's sludged, or if you used the wrong coolant, or deathcool. But in 99% of cases there is no need to flush.
Since a fair amount of coolant hides in the heater core and in other coolant lines I always find a flush is better value. It ensures that 100% of the old coolant is gone, and that there is 0% chance of any weird coolant chemistry happening.
Chrissfix did a good video on youtube. my technique is slightly different.
After draining the coolant, I then run the garden hose into the bottom radiator hose and have the car run with the heater on until the discharge coming out the bottom of the radiator is clear. If your coolant system is dirty, disconnect the top radiator hose and have it discharge directly from here. Take the rad out and clean it.
Once you're confident it's all clean, you can then choose to do a 'chemical flush.' If you do repeat the previous step to ensure all the flushing agent is removed, after following the directions of the chemical flush.
Afterwards, fill with distiled water and run for a short while.
Refill with a coolant of your choice that meets the manufacturer specifications. (I personally like Nulon coolants here in Australia.)
guaranteed 100% clean. No old coolant. But does make a mess from running a total loss coolant system during the cleaning phase
Trade it in on a Dodge. Coolant is 10 year/150K mile OAT.
Dodge coolant changes are free with all major engine work
Let see, in the last 50+ years I have owned 87 cars and trucks almost all GM, Ford, or Chrysler products. Never had any major engine issues except with Fords (specifically Ford trucks). Had a lot of transmission issues with GM trucks. Have had no major engine or transmission issues with Dodge or Ram products and I don't have to worry much about coolant changes! One man's experience.
Most important part of coolant flush or even drain and fill is to use distilled water. The premix should come already mixed with distilled. The concentrate still comes out to be significantly cheaper when mixed with an 88 cent gallon of great value distilled water.
Flush the coolant with the engine running ?
Guys here tell me it's safe because the water pump has a sealed bearing, but in the old days if you tried to run the water pump with straight water, it would burn the pump up. The coolant, being as slippery as it is, was the oil for water pumps back in the day before sealed bearings came about. I'm still too scared to do it; I just drain and fill.