I have looked around for drain plugs on the 5.4L V8 engine and I can only seem to find one. The plug I found is on the drivers side and appears to be hex keyed. I have a couple of questions.

Is this a engine block coolant drain plug?

Is there only one engine block coolant drain plug on the 5.4L V8 engine?

 

Yeah, thats the coolant drain plug. Don't know if there are more, but you pull that one and the coolant comes out in a hurry. That's where I stuck my water temp probe for my meter.

 

Thanks Rocketir! I read a thread in here about someone adding a temp gauge and how a 3/8 inch tread was and exact fit for it. Maybe that was you!

I also attached a picture above for the benefit of others in the future. Im going out this afternoon to start draining the coolant.

 

There is one more on the other side too. You just can't access it.

I've never touched the drain plugs myself. I just drain the rad and drain the resovoir then start a process that will flush out all the old stuff. IMO, if you drain the block and then screw in the plug and then fill the rad, you have the posibility of creating an air pocket in the block. And, you still have old stuff in the pass side of the block, so you need to flush it all out anyway......

rocketir,

I'm curious as to what water temps you are reading with your sensor in that location? My guess is it's probably pretty low..... I mean, the coolant has not had any chance of running past all 8 cylinders or either head for that matter..... That's where all the heat is generated. I think you are only reading the 'coldest' temp the coolant gets.

I've got mine in the heater hose that is leaving the head on the pass side and enters the heater core. This coolant has gone through the entire engine and is just about ready to go into the core and then to the T'stat and finally to the rad. So, it'll read the 'hottest' the coolant is. My temps are a steady 190* with it going to 195* on occasion when it's hot and I'm working the engine (towing a #4500 travel trailer).

My process takes a couple hours and lots of water, but it gets the job done and I like doing it. I do it every 18 months. That reminds me, it's only six months to go till the next flush!!

 

Never mind the access it, I can't even find one on the passenger side. The Haynes manual says the 5.4L V8 engine is supposed to have 20.8 quarts of coolant, but I was only able to drain out 12 quarts from the radiator and the engine block. I have cleaner in the engine now will drive it around for a few hours tommorrow. Then its back to draining again and then adding distilled water and antifreeze.

I had to use a 5/16 inch allen wrench to get the engine block drain plug out. It did not take much force to get the plug out but I sprayed liquid wrench on it about 30 minutes before I removed it.

 

That probably includes all the hoses and the heater core as well. Probably also depends on what "size" rad your truck came with too. I know there was a heavy duty one and a standard one early on.

IMO, you can never get "all" the coolant out by just draining, even if you could get to the pass side drain.

When I do mine, I drain the rad, fill it up with water and leave the rad drain valve open. Run engine and watch the water level. When the t'stat opens and warm water begins to come out the drain, shut engine off and let drain. I'll do this a couple times until it can run for about 15 minutes and only clean (hot) water comes out.

Drain rad, close drain and put in favorite flush product. I like the kind that says to only run at full operating temp for 10 minutes or so. I do this by driving around the neighborhood some and letting it run in the driveway. I then shut engine off and let it cool down for at least an hour.

Then I do the above process all over again to get that crap out of the system. It's amazing how dirty the water is after this flush.

I finally just add 2 gallons of AF to the rad and then top off the resovoir with 50-50 mix and run it again for awhile. Keep an eye on the level and the temps for the next couple days and it's good for another 18 months!

 

Temp1,
What you do is drive your truck up on one ramp under the passenger side tire to tilt you truck to the drivers side. The block cooling system is one big cavity in the block, so anything on the passenger side will flow to the drivers side drain. If I had to guess I would say the fully loaded the block would hold about 2-3 gallons of coolant.

 

Yeah it is lower than 190. Usually its around 180-185 and it doesn't flucuate that much. Sometimes during the summer it gets around 190-195. 200 is the max I have seen. I stuck it there cause it was easy to do. I was supposed to go back and tap the heater hose, but I haven't done that yet.
Jes

 

Thanks for the info. I would have thought it would have been a bit cooler then that, but there you go.

 

Wow thanks everyone. I was under my truck for 30 mins looking for drain plug. Every description I could find said nothing about allen wrench. But with picture I know what I am looking for. Thank you again. So you say don't bother with engine drain plug ?

 

Someone is digging up bones again ........ (Nov 03 ??)

 

No complaints here. Search feature FTW!!!

 

I agree

Also, sometimes the only way you can get that Allen bolt out without stripping it , is with an impact.

 

​​​​​​I'm glad people add solution and comments! I'm relying on everyone's input! Thanks.