Gracefully draining a Cummins 450C raw water system?

For those unfamiliar with these engines, there are three zinc anodes: upper and lower aftercooler, port side, and under the heat exchanger, starboard side. The raw water system also includes oil cooler and gear oil cooler, and in our case, small lines to the dripless shaft seals.

It's sort of easy enough to drain raw water from our starboard engine from the lower aftercooler zinc into a trash bag. Remove the top aftercooler zinc, then remove the lower zinc and tend the bag. Seems like about 5-6 gallons of sea water...

Our port engine is more difficult, given the two aftercooler zincs are on the outboard side. There's not a lot of space between the zinc port and the engine bed rail on that side (which is actually notched to get a tool on the zinc)... and it's awkward to get down close to the action anyway.

So I thought I'd try draining that side with a transfer pump, out through the top aftercooler zinc port. Got a fitting to screw into the aftercooler and convert to garden hose threads on the other end. Remove top aftercooler zinc, short hose to transfer pump, long hose from pump to overboard, what could be simpler?

Except it didn't work. Not even a little.

Hmph!

Back to the bag, but of course that process isn't all that elegant on that side, lots of raw water escaped into our bilge... and I hate that!

Anybody know why my Rube Goldberg approach didn't empty our system?

-Chris

Not much you can do if no good access to area underneath AC for a bucket. Maybe a couple of beach towels.

I have the same engine, but a single, so everything is right out in the open. When I take out the lower AC zinc plug, I'd guess I get about a gallon, maybe 1.5gal. Think a couple of beach towels could hold that.

Or a big wet dry shop vac. Hold hose near zinc as you unscrew it, let vac suck the water as it comes out.

The shop vac is the bomb for messy liquid removal jobs!
You can make a custom collector funnel out of an old plastic bottle, cut it to fit nicely and duct tape it in position with the vac hose over the neck.
Find a lower drain point, if there is one, it might require a tee fitting on an existing fitting, and fit a small valve with a barb to the port. It will simplify the process next time.

I got way more than 1½ gallons when I did the starboard engine (zincs on the inboard side). Maybe only caught a couple gallons in the bag out of the port cooler, but I think a boatload wandered down into the bilge and I haven't found it all yet... as usual.

I'd just barely have room to use my small 2-gallon wet/dry vac on that side, but the quantity seems to be more than that...

No obvious lower drain points, without inserting a new water fitting into the system somewhere; not enthused about that...

I guess I'll have to go back to the funnel, hose (stuffed into the aftercooler after the zinc comes out... with some Keystone Komedie involved), bag, etc. approach. Beach towels sound like a good idea, thanks for that. Some of this would be easier if I could actually see what I'm doing at the same time.

-Chris

Or... I wonder if maybe it was just a priming issue. Maybe I should have back-filled through the hose to the top of the aftercooler with freshwater first, then tried the transfer pump...

??

-Chris

I change my AC zinc after engine has been shutdown for like a day at least. That might allow water to slowly drain down through the sea water pump. Maybe that is why mine only drains a gallon or so.

I also just put a plug in the upper AC zinc hole (no zinc) as it is just in the air soon after shutdown. If zinc is not submerged, it does no good.

I have a smaller engine, Cummins 5.9L QSB. I get less than a gallon of water out of the aftercooler when changing anodes in the after cooler and less than a pint out of the Hx. I have a pretty easy time collecting the water with a small bucket under the aftercooler and a water bottle with the top cut off under the Hx.



This may be a dumb question but... what would be the problem with allowing the water to drain into the bilge and letting the bilge pump empty it? A quick rinse with fresh water would take care of any salt or bilge smell.

My motors drain down through the shaft seal lines after shutdown except for about a quart in the bottom of the aftercoolers. Lines come off the gear cooler which is about half way up the system. Makes it easy on mine.
Also, the first post notes the oil cooler being cooled by sea water, just to avoid any confusion, the 450c’s oil is cooled by coolant.

Did your transfer pump setup provide for air to get into the cooler? If no air in no water will come out.

If your engine setup is similar to the 6BTA5.9 aftercoolers the water level drops in the aftercooler after shut down and the top anode is above the water level. This might be why you can't suck the water out of the top fitting.
Our port engine was similarly hard to get to the bottom anode and drain it. Like you I hate any water in the bilge so just drain it into a 2 liter ice cream container 1.5 liters at a time until its empty.
If you could place a container under the outlet that would catch the water you may be able to suck it out with some sort of oil drain vacuum pump in the container.

I would say the pump failed to work as it was drawing air through the other end of the heat exchanger. (Which is connected to the exhaust hose, open to atmosphere)

Try pumping from the last hose in the circuit. (The exhaust hose)

It may work, however, as it starts to create a vacuum you may have to crack your seawater strainer to let a small amount of air in.

Hope this helps/works

Ski in NC said:

I change my AC zinc after engine has been shutdown for like a day at least. That might allow water to slowly drain down through the sea water pump. Maybe that is why mine only drains a gallon or so.

I also just put a plug in the upper AC zinc hole (no zinc) as it is just in the air soon after shutdown. If zinc is not submerged, it does no good.

Click to expand...

Hmmm.... I did each engine on different days, can't remember how long between our last run and replacing the starboard engine zincs. That could very well be applicable here, though, now you mention it. I really did fill a 5-gallon bucket from the starboard aftercooler.. but then it didn't actually seem like I had that much from the port side... more like maybe a gallon or gallon and a half... and it's been several days since we've been out running the boat. I'll check my log.

Thanks for the tip about just using a blank plug on the upper fitting. I've wondered about that, but I've been hesitant to replace with just a plug.

dhays said:

This may be a dumb question but... what would be the problem with allowing the water to drain into the bilge and letting the bilge pump empty it? A quick rinse with fresh water would take care of any salt or bilge smell.

Click to expand...

Our bilge is compartmentalized, so water takes days to make it's way to where the bilge pump lives... and I just don't like salt water wandering around down there, all by itself, looking for mischief to cause.

drillguy said:

My motors drain down through the shaft seal lines after shutdown except for about a quart in the bottom of the aftercoolers. Lines come off the gear cooler which is about half way up the system. Makes it easy on mine.

Also, the first post notes the oil cooler being cooled by sea water, just to avoid any confusion, the 450c’s oil is cooled by coolant.

Click to expand...

Similar to what Ski said; maybe I just need to pay attention to "drain down" time.

Ref cooler: noted, thanks for correction, I meant fuel cooler.

hmason said:

Did your transfer pump setup provide for air to get into the cooler? If no air in no water will come out.

Click to expand...

Yes, but... maybe too much air to allow priming.

Jetstream said:

If your engine setup is similar to the 6BTA5.9 aftercoolers the water level drops in the aftercooler after shut down and the top anode is above the water level. This might be why you can't suck the water out of the top fitting.
Our port engine was similarly hard to get to the bottom anode and drain it. Like you I hate any water in the bilge so just drain it into a 2 liter ice cream container 1.5 liters at a time until its empty.
If you could place a container under the outlet that would catch the water you may be able to suck it out with some sort of oil drain vacuum pump in the container.

Click to expand...

How do you control flow so you can get only 1½L at a time? Once our bottom plug is out, it's pretty much fire hose; haven't been able to start the plug back into the threads to shot off flow for a minute...

Not enough room to do much on our port engine. The only container I've been able to use is a trash bag... which would work pretty well if I could hold it with two hands so flow actually goes into the bag all the time. As it is, I'm sorta spread out, reaching down and holding the bag open with only one hand...

bluebyu said:

I would say the pump failed to work as it was drawing air through the other end of the heat exchanger. (Which is connected to the exhaust hose, open to atmosphere)

Try pumping from the last hose in the circuit. (The exhaust hose)

It may work, however, as it starts to create a vacuum you may have to crack your seawater strainer to let a small amount of air in.

Click to expand...

Yeah, I think maybe I had too much air. Tried opening the heat exchanger, no workee, tried closing it, no workee, tried slightly opening the bottom aftercooler zinc, no workee, etc... no other easier places to attach the transfer pump.

Seems like I'm just going to have to get more graceful about channeling water into the bag, holding the bag, not dropping the bag and so forth...

-Chris

ranger42c said:

How do you control flow so you can get only 1½L at a time? Once our bottom plug is out, it's pretty much fire hose; haven't been able to start the plug back into the threads to shot off flow for a minute...

Not enough room to do much on our port engine. The only container I've been able to use is a trash bag... which would work pretty well if I could hold it with two hands so flow actually goes into the bag all the time. As it is, I'm sorta spread out, reaching down and holding the bag open with only one hand...

Click to expand...

I undo the anode plug so it's just out of the threaded section and hold it there. That way I can control the flow into the container. I have to squeeze between the cabin floor and engine and lean over the top of the engine down into a very tight space to reach it so it sounds similar to yours. I haven't had any trouble just screwing the plug back in a couple of turns between containers. Also I chock the container in place while filling it as the plug can only be reached with one hand.


What I was thinking was if you could drain the water into a container that has the suction hose of that fluid vacuum pump hose in it you might be able to suck the water out of the container fast enough that it wouldn't overflow. they hold about 6 liters so around 1.5 US gallons.

Jetstream said:

I undo the anode plug so it's just out of the threaded section and hold it there. That way I can control the flow into the container. I have to squeeze between the cabin floor and engine and lean over the top of the engine down into a very tight space to reach it so it sounds similar to yours. I haven't had any trouble just screwing the plug back in a couple of turns between containers. Also I chock the container in place while filling it as the plug can only be reached with one hand.

What I was thinking was if you could drain the water into a container that has the suction hose of that fluid vacuum pump hose in it you might be able to suck the water out of the container fast enough that it wouldn't overflow. they hold about 6 liters so around 1.5 US gallons.

Click to expand...

Ah. Thanks. I haven't had much success routing water as it drains out if the plug is still partially inserted. Seems to go every direction but the one I can (sorta) capture. Maybe I need more experimenting with that.

If I could get a hose on it fast enough, the transfer pump would surely suck the water our easily enough. A local recommendation was to use raw hose -- i.e., no fitting, just stuff it in there as quickly as possible after the zinc exits -- as either a simple drain route or to connect to a pump or whatever. If I could get a hose in there and secure quickly enough, just routing the drainage to an easier catch pan would be a step forward.

I'll probably try all these ideas, next time...

-Chris

I have Yanmar engines, so a little different than Cummins. I have a complete anode and plug ready to install. I remove the old plug, stick my finger over the hole, set the old plug down, grab the new plug, and quickly put it in the hole. Less than a cup of water spilled. This even works when laying over the top of the engine. If you can touch the plug with two hands it's easy to do.

dhays said:

This may be a dumb question but... what would be the problem with allowing the water to drain into the bilge and letting the bilge pump empty it? A quick rinse with fresh water would take care of any salt or bilge smell.

Click to expand...

There's more to my first comment, too, Dave. Not only is the place compartmentalized, but the last three compartments en route bilge pump are under raised flooring... and any water in the bilge is often trapped in those three compartments, don't actually make it all the way forward to the pump.

Which means I have to find someplace to be when I lift each segment and vacuum under it, etc. It's not quite as bad as standing on flooring segment and trying lifting the same one but it's close.

porman said:

I have Yanmar engines, so a little different than Cummins. I have a complete anode and plug ready to install. I remove the old plug, stick my finger over the hole, set the old plug down, grab the new plug, and quickly put it in the hole. Less than a cup of water spilled. This even works when laying over the top of the engine. If you can touch the plug with two hands it's easy to do.

Click to expand...

Hmmm... Sounds more elegant than I've been able to do so far. I don't think I can get two hands close at the same time, but I'll probably give that a shot, too, next time I wrestle with it... probably coupled with that beach towel idea... Thanks.

-Chris

I like chasing the hole threads with a tap to clean it up, and to look in the hole for impeller bits (thanks Sherwood). So I don't bother with trying to do it quick. I seem to get about six months out of a zinc, so don't do it that often.