When doing a coolant flush, the Haynes manual says that there are two drains for the coolant on both sides of the block, located an inch or two above the oilpan. I only found one, so I drained it (in addition to the rad..etc.) I tested the mixture of water to coolant with a hydrometer after the fluch, and it seems fine. Has anyone done a flush on a 4.6 and found both drain plugs (alan-key hole type)?

Can I assume that if the hydrometer is reading it as a good mix that it is, or is it possible that since it is so hot lately, and with the duals on my truck (keeping the temp. down) that the thermostat hasn't opened up and sucked in all of the coolant from the resevoir yet?

sorry for the long post.

 

Defacto:
I'm about to do the same thing to my 4.6l.
Thanks for starting the post.

Were you able to actully flush the system or just
drain everything and fill it back up. I know it's
hard since there is no Rad. Cap.
Not like the old systems, where you drain from
one end and flush with a hose on the other end.
Thanks for the feed back!!
Good Luck!!!


1998 Silver F150 4X4 ORP Scab 4.6l TRITON

 

you really don't have to drain the block.

what i did was:

turn engine on

let get hot and check for warm rad hose

unscrew rad reservoir cap

begin draining radiator (it will be hot. watch out)

hang a hose into the reservoir

obtain equal in/out-flow of water/rad fluid flow

make sure you have somewhere to contain/dispose rad fluid

watch out-flow until it's pretty much all water (this will take a while). during this time, be checking temps and stuff from dash.

turn off engine and water hose.

let all hot water drain from rad

close rad drain plug

refill rad w/rad fluid (appr a gallon or so. only need appr. 1 part rad fluid 3 part water even though manual says more)

turn engine back on. let get hot. fill rad res to normall operating level with water

put rad res cap back on.

This procedure pulls all the fluid out of the block and radiator without having to unbolt the block drain plugs. When you do the step of turning engine and hose off, you are leaving about 10 or 11 quarts of hot water in the block. The rad holds the rest of the coolant system fluid. About 6 to 7 quarts (haven't done it in a while. Plus, I have the 5.4L, so amounts are different). Either way, the ratio of fluid in the block to the fluid in the rad is about the right ratio you want of water to rad fluid.

general proc, but overall right idea. think about it. mechanic at ford helped me on this one. pretty knowledgable guy. down here in home town. surprising.

-Joel

 

I do pretty much the same as red bull. Except my first step is to drain the rad first, when it's still cold. Fill it backup with water, then run engine (leaving the rad pet**** open). When top rad hose starts to get hot, I wait 30 seconds and then shut off engine. Let rad drain. You should see that old antifreeze is draining again. Fill rad with water again, run engine (still letting rad drain at same time). Repeat until only clear water drains from rad. Fill rad with pure antifreeze, mine took 2.5 gals. (block still has pure water). Run engine until mixed and water level is at the mark.

 

I ended up doing it twice, because the first time I didn't drain the block and the hydrometer read that the mixture was WAY off. The second time I did it, I drained the one plug that I could find on the block, and the mix was much better, however, it still reads that there is a bit too much water. Here in Toronoto, the summer gets really hot, and the winter goes down do -35 degrees Celsius which is -31 Fahrenheit so the suggested mixture is between 50/50 to 70/30. I've always used something like 60 to split the difference. So with only one side of the block drained the mix is close enough to reach -35 as is (which is kinda close for comfort). What I'm curious to know is if the plug that I drained from drains both sides, 'cause I can't for the life of me find one on the passenger side.

 

On my 4.2L I could only find the block drain on the drivers side. From my experience with this I would suggest that the block is drained and not just the radiator.

What I did was drain the radiator and flush it with a garden hose. Then I filled it with distilled water and Prestone radiator flush. After filling the radiator I drove about 10 miles to get the Prestone flush through the entire system and let it sit overnight because I had trouble getting the Block Drain bolt loose. In the morning I did get the drain bolt off and all sorts of grimy flakes came out. It looked to me as though this build up was stored at the bottom of the engine block because I had always had the dealer change my coolant and they don't remove the drain bolt in the process so it had collected down there for 65,000 miles. After everything drained out I then ran the garden hose through it for about 5 minutes until the water was clear. It took about 2 gallons in the radiator on refill and about 2.5 gallons more in the engine block (this is 4.2L). This was 3 months ago and my overflow tank still has perfectly clean coolant and reads a steady 50/50 mixture.

 

AjRagno:

You mentioned the coolant levels; did you find that the manual and what you actually put in were not the same? This is one of the reasons I wonder about finding another bolt.

I too had a hell of a time trying to get that bolt out. I put anti sezie on the lower end of the threads so that 2 years from now I won't have to go through that again.

 

You can remove those drain plugs in the block and replace them with the appropriate sized pet****s like the brass ones that come on radiators if you have room. Next time you won't need a wrench.

Also, another benefit of draining the the block is that you get out the all the slag and crud that settles at the bottom of the water jackets . This stuff usually wo'nt circulate to the radiator.

If you have the time and patience you can remove the thermostat completely for the duration of the flush and really watch that stuff circulate and carry away more gunk quicker. The liquid really moves through the cooling system without the stat restricting it and engine temp is no longer an issue for good circulation.

 

Regarding the level of coolant that I put in;

It was confusing but I ended up adding a total of about 4.5 Gallons overall. My confusion came from the process I was forced to use when I couldn't get the block drain bolt off. I had drained the radiator then went after the engine block and when I couldn't get the bolt loose I refilled the radiator with about 2 gallons of coolant. What I later realized is that when I drained the engine block, the coolant in the radiator did not come out so I only needed to add another 2.5 gallons to bring everything up to level. I was quite concerned that I could only add a couple of gallons until I realized why. When I was flushing the system with a garden hose I think that the water was just going right to the engine block,bypassing the radiator. I don't know why it worked out this was but my cooling system is working well.


Another thing that I found was this engine block drain bolt is a complete pain in the A@&. I tried everything I could to get it loose until I realized that this square drain bolt is 1/2 inch and that a socket has a 1/2 head for the wrech. What I did was put a 3/8 allen socket on an extention of my socket wrench and then put a 3/8 driver into the allen socket and put that on the drain bolt backwards because the opening for the socket wrenk is exactly 1/2 inch!!!!! Confused????? Worked great. Plenty of leverage and it fit perfectly:o)

I don't look forward to doing this again but I sure the next time witll go smoothly.