Block drain plugs

I have the heads off the 304 and noticed water in the block was brown and cloudy as opposed to the fluid from the radiator which was clear and green. I removed the plugs on the side of the block, rear of the motor mounts. No water drained as I expected. aren't these block water jacket drains? the 75 TSM dosn't address this.

 

I'm not familiar with the 304, but, from my experiance with other motors, yes, those are the block drains. If this is an old motor, you will have alot of built up crud laying in the bottom of the water jacket. If so, you'll probably have to use a coat hanger or something similar to drill thru the crud to get the water to drain. Keep in mind that you'll never get all that crud out unless you completely dissemble the motor and have it hot tanked. Even then you'll probably have some remain inside as it's been packed in thereall these years.

 

LarryD,
I am also not that familiar with the 304, but are the drains that you remioved from the side of the block threaded intoi the block ??

 

Yes they are on the side of the block about 3 inches to the rear of the motor mounts. They are 1/4 npt, I will try the wire probe. On the F134 there was one on the side just to the rear of the distributor.I took a garden hose and flushed the water jackets until the water ran clear but I had planed a chemical flush and am concerned I would never get the chemicals out as it seems the water dosn't circulate in the block.

 

On one of my engines, I adapted from a block drain up to a garden hose fitting, allowing me to back flush with house hold water pressure... it worked very well and got a bunch of stuff out of the block..
Also, isn't it Arm and Hammer Super Washing Soda that is a good block/radiator flush with out using harsh chemicals ????

 

I probed and prodded with wire and even tried compressed air with no results. I will back flush with a garden hose with the heater hose fittings on the intake manifold until the water runs clear, it just seems strange there are 2 plugs on the side of the block with no good purpose.

 

Are you sure they aren't oil pressure passages? Just a thought.

Pete

 

I'll find out this weekend. I got the heads back from the machine shop today and hope to fire it up Sunday. I did'nt put the plugs back in so we'll see what happens. It would be great if they are oil galley plugs cause I would like to add a mechanical oil gauge.