Rust in block

Bob Kerns · May 3, 2013

I just had my old 9n engine rebuilt a couple of months ago. I had to pull it down this week to replace the oil pickup tube, the machinist assembled the bottom end and I had carefully checked the tube beforehand, now it has been "sealed" with RTV and it broke loose during the break-in period and the new rear seal leaked. "If you want something done right,do it YOURSELF".
Anywhoo, when I dumped the coolant it did not appear to have mixed despite several hours of continuous mowing and other use which should have heated it up. The block was full of what appeared to be plain water with a LOT of rust in it.I had put in water and then antifreeze in roughly a 50/50 mix when it came back. Supposedly the engine was hot tanked and I installed a new radiator and thermostat.
Any ideas on why just plain water in the block?

souNdguy · May 3, 2013

non op water pump? bad thermostat stuck closed? lots of luck it did not overheat...

Den N Ms · May 4, 2013

Bob,you say I had carefully checked the tube beforehand, now it has been "sealed" with RTV and it broke loose during the break-in period.Well if you put it together you will be doing it again,RTV won't work! The pickup tube and cup needs to be brazed or silver soldered for it to last.Remove the hose from the head,and water pump ush till water runs clear,then back flush with hose connected to block drainalso remove block drain and flush block with water hose jammed in the head hose connection.flush till water is clear.Then back flush with water hose connected to block drain.Remove thermostat from hose and test in a pan of water on the stove and see if it will open.

Bob Kerns · May 4, 2013

Den N Ms - I didn't try to seal the tube with RTV, it came back from the machinist like that. I'm almost positive it wasn't that way when it went to him. I had him assemble the whole bottom end because my shop is multipurpose and is always full of too many different projects with sawdust and worse swirling in the air and all over the floor. I thought his shop was "cleaner". My guess is that he managed to knock the tube loose (easy to do, given its length and location)and "sealed" it back up with RTV.I didn't want to say in the original post "he did it" because I'm not 100% sure, only 99%.
BTW my new oil pickup tube from YT (it's brazed) just arrived along with the oil pan gaskets and rear main rope seal so now I can begin to reassemble the engine! I'll check the thermostat and the output of the water pump and this time I'll premix the water and antifreeze before it goes in the engine!
Thanks for the replies.

Rust in block

Bob Kerns

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souNdguy

Well-known Member

Den N Ms

Well-known Member

Bob Kerns

Member

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