Changing thermostat just curious as to weather to do a flush or not, thanks for any help.

 

You will want to change the thermostat before flushing so you know it is circulating. Motorcraft E5TZ-8575-C thermostat is less the $20 at the dealer is is highly recommended. The job takes a couple of hour so I would not try to save $5 by getting a thermostat at the parts store.

I double flushed (each for 2 days) and got old tea colored water with both flushes. Definitely worth the effort as the "tea" is insulating the inside of the block and radiator. I would suggest you use to leave the flush in for a week and run it every other day enough to circulate the water. I did that with my `64 F100 and the second flush was clear. That will save a lot of time and likely remove more than my double 2 day flushes. I do not think the brand matters. I think it is all that is available is some form of citric acid.

Also be aware the block holds 3.5 gallons so you need remove block plugs which will get 2 more gallons out. Take your heater hoses off and flush the heater core. After the flush period, I recommend flushing with water and draining then filling with distilled water to dilute the remaining 1.5 of flush left in the block. I left the distilled water in the block overnight to let it soak up all the flush that it could then drained the radiator and block. I added the require 4 gallons of Fleet Charge first so to insure I had the right amount of good stuff and topped off with distilled water.

This might be overkill but I live in Texas where we see road temps in the 110-115 range 4 months of the year.

With new thermo and flush she went from 230 degrees on the road to cycling between "N" and "O" in the normal range.

 

Thanks......