The Stovebolt Site Forums The Shop Area Engine Shop No flow from block drain - 216

I am tracking down why my 216 runs hot. OK on a cool day, but if 90+ I am headed for boilover if I don't stop. So I am going though some basics first - radiator, thermostat, all the simple stuff. If I open the drain at the back of the block though, nothing drains out. There is no blockage right at the drain itself - I took the valve out, and poked around a little with a wire there. If this is a blockage in the water passages, at least down somewhere near the drain, is that an obvious possible cause of the engine running hot? I know there are many posts on overheating here, but I'm not sure I was this topic exactly.

Thanks,

Pat

If you take out the petcock you should be able to poke a long screwdriver or wire in it & it will gush out. They do accumulate a lot of crud down there & that can cause overheating. You may have to pull a freeze plug to flush it out.

That area of the block seems to be a common area for blockage. When I rebuilt my engine I found the same problem as I prepped the block. I couldn't blow air through it. This was after scrubbing, pressure washing, and hot tanking. As George indicated above, poking at it should loosen the crud.

In my case I didn't think it would ever break loose and I wasn't going to rebuild a block like that. I tried all kinds of wire and had the best results with o/a welding rods. I even made up wire devices that I spun with a drill. I got a little hard black crud out each time and using compressed air helped. I worked at it and left it at least 20 times before it finally broke loose.

In my engine this same hard black crud had the water pump frozen up too. The truck sat for 24 years and I don't know if this was present the whole time or developed as the water evaporated/leaked out.

Hope it goes easier for you.

Chuck

i suggest removing all the frost plugs and flush everything out. i have in certain instances to clean up some water passages used liquid drano. pull all the hoses off the radiator and heater core before filling the system. plug off the lower rad hose and both heater hoses and fill the system with a solution of drano and water and let it sit for a good half hour then flush the system completely with fresh water the longer the better as you dont want any of the drano left in the system. call me crazy but iam not the only mechanic that has done this. its beginning to become a common pratice for cleaning out the newer vehicle heater cores up here in the north country. later MO

I'm having same issue. Petcock is out and bunch of black crud is out. I can get get a screwdriver to go about six inches into drain. I removed freeze plug and poked around with a wire. Plenty if rusty crud on bottom of block if i poke around the freeze plug hole. How far into the drain hole before it goes up into block? Thanks

One simple solution is to remove the thermostat, Blow low pressure air (50 psi) into the drain hole and watch it come out the thermostat housing. The solids settle to the bottom and plug the drain hole. Repeat as necessary.Follow up with flushing the system and see if it still over heats.

Thanks. Mtneermike. I should have mentioned that I'm trying to drain it as part of removing the engine for rebuild so all the components have been removed. I spent a fair amount of time with a hanger today. Im guessing i should be able to free some of it up by sticking the hanger through the freeze plug but don't know what's between the freeze plug and drain or where to aim the end of the hanger. Maybe i should just pull the engine and watch it drain out the freeze plug all over my garage while the mrs is offsite?

Compressed air sounds like the way to loosen it up, as Mike suggested......
John

if anything it might just pack it in there tighter and i consider it a waste of time but you can try it.

i havent had a truck where anything came out of the block drain yet. if your not tearing the engine down then full patience is in order. if you tear down the engine full patience is in order being in the 1000 hp boiler business its easy for me to approach it. its like a block that sits for a long time and it didnt get stuck over night and the cooling system is the same. years of bad water and no maintenance and it will take time to unclog and clean it and even then you wont get it %100 clean. when i did the 59 for my dump i used some h.d boiler cleaner(hah) and left it sit for a week before i started cleaning. with the large hole in the front for the water pump made it easier access but you dont have that luxury. i used a home snake on the end of the drill for days before i was satisfied. fill, snake, drain, flush over and over. using a little light looking down in the passages around the cylinders starting at the block drain and working forward. replace every sand hole plug on the side and rear of the block during build. now it flows out of there like it did when i was in my drinking days

if your not tearing anything apart then this is what i did on my 228 for the 40. i started with the rod that i use for changing the head on my weed wacker. i had to pound it in with a hammer and pull it back out with vise grips. its around 7" long and used every bit of it and nothing came out. got something longer and it started to weep. over time i got it to flow and had to use a welding rod and kept using something that was big enough and able to get around #6 cylinder. fill and drain over and over. i was catching what i was getting out in a bucket to monitor what was coming out and how much. to simplify the task i used a 1/8" ball valve screwed into the block and used the rod through the ball valve. your drain hole may be 1/4" which is bettter because it lets the bigger chunks you break free come out and not get stuck in the smaller opening. sometimes the chunks are so big they can't come out of the block until you bust them up. when its flowing fairly decent and you get tired which you will fill it with water and take a break and go for a ride. when youi get home start over. i did this for over a year and it wasnt until about a years point i started saving what i was getting out. im sufe everyting i got out would fill a big coffee can. when its flowing clean and good its no means clean. with the ball valve is easy to just pop it open blow out any scale that broke free and motor on. for this whole process i only used distilled water during the driving season and filled it with anti freeze for the winter lay up. im anal about looks and originality. this is one place i have it set up for ease and functionality along with the radiator. you need to drain and flush that too because what you kick up driving around will end up in there also. if you leave the ball valve in put a plug in the end snug. over time you should see a difference in operating temps

Great advice thanks. I spent 3-4 hours on this yesterday and now realize I am only starting.