My 1999 4.6 only drains about 8 qts of water. Books says the system capacity is 23 qts.

How can the system be effectively flushed with this little being drained at a time? Last time I went to a lot of trouble and most of a Saturday, by flushing multiple times with city water followed by 5 flushes with distilled water and still did not run clear. Seems like I got 2 gallons and a little more of AF back into it.

This time I was just going to drain and refill with 50/50 thinking the old had the same concentration. however it read around 0F using a floating ball hydrometer. So I refilled with about 7 qts of 100%AF and the next day the hydrometer only read -10F

How can you get a good flush and the right amt of AF in the system. Or am I going overboard in trying to get the system flushed and cleaned.
Thanks, Mike

 

Make sure the petcock is opening up properly then go buy some descent radiator flush and follow instructions

 

It is open and loose in the connection.

Am I to understand that more than 8 qts should be drained out?

I even blew air from the back side of the shop vac to see if that would push more out..only a pint or so.

 

That is about what the radiator holds, rest is in the block, heater core and hoses. Short of taking the block plugs out you can take the T stat out and run your garden hoses in the opening to flush the block somewhat, can also drive with the above mention radiator cleaner for a day or two with water only.

 

I always buy the flush kit (usually around $5.00 I think) and install it. It consists of a plastic "T" which you install into your heater hose. don't recall now which one, but the instructions tell you.

You hook up your garden hose to the tee and it backflushes the system getting the majority of the old coolant out. Works very well, and been using them for over 30 years now.

Video: Installing a Coolant Flush Kit | eHow.com