is there a drain petcock which wich will drain ALL the water from the water jacket?
I ask because as I am digging through the rusted cooling passages, I still can not see where there could be another spot to drain the block.
If you are to strictly drain via the water plug in the radiator pipe, there is still a 1/2 inch of water in the block due to the design of the water pump.
Anybody have input or better yet a picture showing cooling passage outline?
Thanks!

Look on the left side of the block back toward the bell housing and see if there is a drain cock or a hex plug going in the lower part of the block about where the bottom of the liners would be and above the side covers. That,s where it shows on an R2 and the block is quite similar as I don,t have a D2 book.The D4 7J is on the left side too so I,m sure that,s where it is on the left side.I have drained lots of the D2s, D4s & D6s and that,s where they all are.

"SJ" wrote:

Look on the left side of the block back toward the bell housing and see if there is a drain cock or a hex plug going in the lower part of the block about where the bottom of the liners would be and above the side covers. That,s where it shows on an R2 and the block is quite similar as I don,t have a D2 book.The D4 7J is on the left side too so I,m sure that,s where it is on the left side.I have drained lots of the D2s, D4s & D6s and that,s where they all are.

try this ....
www.acmoc.org/ACMOC_BB/showthread.php?t=...Cooling+System+Drain

Kelly your picture shows the drain on the right side so now he is sure where it,s located. I went by an R2 book I had and it shows it on he left but back in the same area so it looks like the diesel engine was switched sides. It,s been so many years since I worked on one and simple things like that slip your mind. Thanks again Kelly.

I was tired when I typed the letter. Hit send and walk away, thinking about it and realized I should have done a search first!
I printed it out and will look tomorrow.
Thanks Again!

Drain cock on the D25J is on the right side at back of the diesel, sort of underneath the pony motor crankcase drain pipe. It drains the back of the diesel engine at the water connection going up into the pony water jacket.

is "meticulous" the politically correct word? Anyways I had the heads on the pony, put the air hose in the top of the pony water manifold. Shot it with air and it sarted to pressure up! It should be venting out the bottom into cylinder 4! I took the heads off and cleaned and flush lots of mud out of the pony. I ran out of water before I could verify good flow back into cylinder 4! Remember Liner #3 is out.
Here is the meticulous part!
I am actually comptemplating to remove the pony to derust the connection between it and the main block.
How many bolts hold this together approximately?

Now if it don't leak water, I'll be happy. I found the mystery drain plug and got it out. The engine block drains out of it after I coat hangered it. If you air pressure the pony water jacket. It pressures up and doesn't blow out of the drain.
Any ideas?

pull the pony motor off and clean it out right. The most it will cost you is a base gasket.

Other than that, you might be able to coat hanger it if you took the top cover off the pony motor, anyone know for sure it that would help access the lower coolant connection. It should be pretty close to the right side head if you can get the right crook on your wire.

It might be tough to get a wire down to the base of the pony through the top cover water passages since there are only two, kind of between the intake and exhaust ports on each cylinder. I agree with ccjersey, I would pull the pony off and really clean things. I've taken some off and found a mound of rusty sediment where the lower water passage is. Once down that far it should be easier to get the passage clean to the diesel drain valve.