So I have a 312 fastech with 454s. Someone has added block drains that consit of a 3/8" hose with the blue little wing nuts on the end. The problem is these are very clogged. So far I have tried poking the out with a coat hanger and trying to shop vac them clear. Both methods are unsuccessful. Any ideas to help me clear these? I thought about disconnecting them at the block, but the motors are so tight together I can get in there to them.

Not much help but that's why I installed these,



Ever year I have to shove a screwdriver into at least one of them to get it cleared to drain. That's why they are straight with a simple cap. Makes them easy to find in the dark bilge. Don't have to try to get a drain plug back in rusted up block treads. No chance to strip the threads out in the block and even works with semi stripped out block threads cause the brass will conform (the reason I did it it in the first place many motors ago).
Cost less then 10 bucks at Home Depot. I just winterized 4 BBC's and block drains were never a second thought and they wont be when I go to plug them again.

PS, you know how many holes feel just like a drain hole in the side of a block when you are searching around with just your hand?

High pressure air. they get packed with sand & shoot.

The single point drain mercruiser uses always made me nervous, how do you know all the water is out? I always stick a screwdriver into each block drain and usually every time a bit of debree has clogged them. Not worth a frozen block, you need to check them or go closed cooled.

If you have a compressor blow air into them till water comes out. then when it stops blow more air in and see if more water comes out. You can easily tell when its unplugged and all the water is out. You will be able to hear air blow in the block. Do this on both sides.Its a good idea to blow air through all the lines, coolers etc. Otherwise you many still have water left behind. Then afterwords you can even pour anti-freeze in if that makes you more comfortable.

Didn't think about blowing air in. I'll give that a go when I get back from my work trip. I just filled it up with antifreeze for the time being.

aluminum welding wire and hope it pokes thru

Beleive it or not we actually run the motor for a few seconds with all of the plugs out. You would be surprised how much water comes out. Then we run on antifreeze.

A few gallons of anti freeze is real cheap insurance