1930 U Plymouth bisiness coupe

[Guest acebopper]

I am about to drain the engine of coolant as I want to renew the antifreeze for this winter. there are, I think three 1/4in tapped bungs on the genarator side of the engine. which one is used for draining the block completly.

[ply33]

I am not that familiar with the 30U through PB blocks, but I'd be looking on the driver side above where the shape of the cylinders shows and suspect you'll only find one there. Lower on the block, well below the water jacket, I'd expect to find a row of plugged whole used for access by the factory for drilling the oil passages. If the three 1/4" holes you are referring to are low and in a line, I'd expect those to be plugging the oil gallery.

[Guest acebopper]

I see. there is an ovel shaped cover at the bottom of the water jacket in the middle, it has one of the 1/4in plugs in the plate, is this the drain plug.

[Guest martylum]

I have a 30 Desoto with the same block design. Far as i know there are no block drains but the lower rad hose is well below the bottom of the cooling passages which aren't very low in the block. If you drain the rad at the draincock you will have drained the block. Be sure to circulate the new coolant if you are draining only water with no antifreeze . Those little plugs lower on the block should be oil galleries. You can tap in there if you want to add an external oil filter.

Martin Lum

1030 Desoto

[Guest acebopper]

Thanks for the advise, all drained now and refilled with recomended amount of blue antifreeze as stated in the hand book.