Coolant change on NHC250

[rbrown225]

Thanks in advance. This is my first time posting.

I recently got a M929 A0 and I am working on doing all the maintence checks.
I am stumped on the cooling system. Per the -23 section 0287 it has 47Qt / 11 3/4 Gal. system
The surge tank was full and I only drained about 7 gals. out of her. I refilled and flushed with water and only used about the same amount. Can not find another drain point. also is there a purge vent on the engine. I would like to get the old coolant out prior to refilling with fresh and SCA additive. Any help would be appreciated.

 

[simp5782]

typical. you can open the coolant access panels on the engine. But you won't get it all out. You may want to pull the covers off the radiator tanks and clean those probably if you had alot of gunk in it.

 

[WillWagner]

There should be a vent line from the stat housing to the surge tank. It will purge itself through the vent line. It is a good idea to remove it and blow through it to make sure it isn't plugged...the vent line.

 

[M35A2-AZ]

There is a drain plug on the block on the passenger side at the back, up behind the exhaust pipe. I think it takes a 7/16" You may get more coolant out from it.

 

[TechnoWeenie]

There is a drain plug on the block on the passenger side at the back, up behind the exhaust pipe. I think it takes a 7/16" You may get more coolant out from it.

Below the port where a block heater goes?

The first flush I did netted muddy brown water. I pulled all the hoses and flushed water through the radiator.... Took about 10min until it came clear.... Then I backflushed through the heater core with just the lower radiator hose disconnected... about 5 mins to come clear..... A large amount of what appeared the be sediment ( fine particles, like mud)came ut....
-
I took some advice and mixed some warm water with Cascade (dish detergent), and filled a 3 gallon bucket with a mix of about 1lb of cascade (not as much as it sounds) and mixed it until diluted....then added it to the water before doing 2nd flush...

2nd flush was significantly less dirty with no large particulates... and smelled like fresh clean dishes...hahaha

now on 3rd flush it has a slight brownish hue, but perfectly see through, and almost no cascade smell....

I'm filling, running engine to temp, shutting down, waiting a lil bit then pulling the lower radiator hose...

I drained it, then pulled the small plug mentioned, but nothing came out.... Is it possible it's higher than the lowest point already drained?

I wanna get as much out before I refill with distilled water and Fleetcharge coolant.. and of course will continue to flush until I don't smell any cascade, which I currently only have a faint whiff of, and the water is not oily or anything (thankfully).

I was told that if the block is rusted I may never get it 'perfect' unless I use a harsh chemical, something I don't wanna mess with, TBH.

This thread was most recent and on topic, so I didn't wanna start another thread for similar answers.

FYI, I've spent a good dozen hours+ perusing the TMs.. I love it... but some information can only be had via 1st person experience. Thanks!