Acid flush raw water side of cooling system

[Jeremy Bendler]

I’d like to flush my QSM11 raw water cooling system with RydLyme once I put the boat back in the water. Is the procedure as simple as:

Remove zincs.
Reinstall zinc holder bolts without zinc.
Close raw water intake seacock.
Detach point where cooling raw water would be discharged through exhaust.
Use bilge pump or livewell pump to push RydLyme through cooling system in opposite direction of normal flow. Exhaust outflow toward the raw water pump.
Collect RydLyme in bucket at the hose that had connected to raw water pump outflow side.
Continuously Re-circulate RydLyme for 4 hours.
Flush system with Fresh water.
Install new zincs.
Reconnect hose to raw water pump, reconnect hose to discharge into exhaust.
Open raw water seacock.
Run the boat.

I have read that I need to plug the outlet going to the prop shaft seal.

Thanks for any tips.

Topic

[firehoser75]

Kopptain,
One more thought. Do you have a cooling line running from one of your coolers (gear oil cooler for example) to a dripless shaft seal? If so, that is where your water is going. That line should be taken off and plugged to avoid this (if that is the case).

[bluebyu]

You may have a coolant line going to your shaft seal.

[firehoser75]

If I am understanding you correctly, then the only thing that comes to mind is a leak somewhere. EG. if nothing is visible, then maybe some water (BB) is leaking into the air side of the aftercooler, or the coolant side of the HX, Oil side of the gear cooler, or the fuel side of the fuel cooler, etc.?????
If that is the case, this is exactly why pressure testing is so important and to do that requires a “full” service, not a BB flush.

[The Kopptain]

New flush questions

Hi all, I have Cummins 480CE engines which is similar to the 6CTA. Based on ideas from this thread and others, I built a recirculation system to flush my raw water system with barnacle buster. I placed my connection just after the raw water pump and just prior to exhaust right after the heat exchanger. Prior to adding the barnacle buster, I used a 5 gallon bucket of water and place both the pickup and returns into the same bucket. The issue I am having is the system continues to take on water meaning that the water seem to be going somewhere. I am not entirely sure as I am disconnected from the exhaust and do not see any leaks. Even know the return was going back into the same bucket, I needed to continue to add water to the bucket. Any ideas where this water could be going?

[firehoser75]

Jeremy,
Unfortunately like most things in life, there are a lot of variables in this.
For example, do you operate and/or moor the boat in only salt water? Do you freshwater flush on a regular basis?
As a general rule of thumb for “top maintenance” (and you do not freshwater flush) you should bench service the aftercooler(s) following Tony’s protocols every 2-3 years, and the other components might be able to go a bit longer (3-4 years) I guess depending on local conditions like salinity, etc. However, why not either implement freshwater flushing (your engine will love you for it) or service all components at the same time at 2-3 year intervals? The time interval on the “other components” may be extended a bit by flushing with Ridlyme, however, they still require a complete servicing which includes a pressure test on a regular basis. The risk of severe damage due to an undetected leak (of any of these components) is not worth it, in my opinion. Photo of freshwater flush setup included (hope it doesn’t show up upside down?)
Hope that helps,

[Jeremy Bendler]

Thanks. Do you all do a full bench service on the aftercooler and raw water cooling system components every year?

[KevinS]

You prety much have the procedure except if you’r eintroducing the flush before the raw water pump then the impeller will need to be removed. A Rydlyme flush is a temporary mid season measure until a full bench service can be done in the near distant future.

[Stephen Oliver]

Pretty much what I do – but I dont reverse flow.. dont see the point – but I start at the aftercooler raw water input through all and out from the HX (on a 6bta) where it connects to the exhaust and back to the bucket.

I dont have a shaft seal feed but yes you will lose your rydlyme if you dont close it.

NOTE – this is not a aftercooler maintenance – if the QSM aftercooler is removeable and strippable then service ON THE BENCH as per Tonys protocol.. I use the Rydlyme as a pre aftercooler strip down process.

Dont forget to dilute Rydlyme 50%…

Steve

[Author]

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