Hi all,

Recently I did a big flush on my XJ and used prestone coolant system cleaner. I disconnected the lower radiator hose from the engine block to drain the system and once it stopped, I reattached it and started filling it with water, but the funnel got pretty full pretty quick and I don't think that my thermostat opened after 10+ minutes of running the car, or there was still left over coolant flush in there because I only used about a gallon of distilled water before I had to stop. (I had the heater running to open the heater core as well). Can someone help me? What am I doing wrong here? Any suggestions are appreciated.

P.S. The water is still brown and i noticed a slight oily tint to the water that came out. Is this a sign of a failing headgasket?

I think your primary issue is you've not properly flushed out the engine and radiator. Remove the heater hoses where they attach to the water pump tube and thermostat housing and use a garden hose to flush the engine in both directions. Also flush the radiator using the upper rad hose. Don't forget to flush the heater core in both directions as well.

^^This! and make sure to do so on cool engine

Completely?
I don't think it is possible.
Dropping the lower hose will get about 2 gallons to come out.
If you have a '96 and down and still have the heater control valve turn on the heater.
Not necessary with '97 and up.
I use the Lisle funnel. Just makes life so much easier doing this.
There is "nut" on the block from what I understand that will let you drain out more coolant.
Don't know where and even if I did wouldn't mess with it.

Well, there is a block drain. Left side, below the freeze plugs somewhere around Cyl 4.

Depending on the grunge, rust buildup, I don't think I would temp fate. Depending on the buildup in your system and how often you serviced it, it may take several flushes
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