Flush A/C's & engines

[lipets]

I want to flush 2 Yanmar 6ly's and an onan 8K


I read the Yanmars have aluminum and some of these may do so damage



Also 3 A/C units Wabasto



I assume the engines need one gallon each and can't reuse the dirty water


The A/c units should need less


Many choices what have you found works well

 

[DavidM]

I wrote an article, Acid Flushing Your Engine. It can be found in the Libraries/Misc section ofthis forum. Link is is the upper right corner of each page.

Read this first as it was based on the Yanmar 6LY and then we can answer any further questions.

David

 

[lipets]

David great write up that cuts thru the chaff of all the misinformation.


Why R U saying to take the after cooler off rather than just flush?


How much of a job it to remove the whole unit ot can I just take off the end caps


Can you please elaborate on that

 

[DavidM]

The after cooler must be serviced before acid flushing because any leak that may open up as a result of acid flushing between the r/w and the air side will force acid into your engine when you flush. Not good!! Also the air side needs to be cleaned as much as the water side and can only be done by removal and pulling the tube bundle to get to the air side. Make sure you pressure test after reassembly.

It is a bit of a job and it took me a couple of hours to remove the air cooler and another couple of hours to get the bundle out. It usually is stuck. Then an hour to clean and another hour to pressure test and a couple of hours to reassemble it.

Now lets talk about flushing the A/C r/w system. First make sure you need it. Check the flow out the thruhull, typically just above the water line on the side. Is it a strong flow? Also check the temp. Should be 5 degrees above r/w temps. Any more or low flow and you have a scale build up problem.

In this case a fill and soak technique works well. Disconnect the discharge from your r/w pump and elevate the hose. Then pour in about a gallon of 50/50 Rydlyme solution through a funnel. Then let it soak for an hour.

Reconnect the hose and start the A/C to flush the acid out. Repeat at least once.

David

 

[lipets]

Dave


As a follow up Yanmar removal, trying to avoid all that work.



Yanmar has a procedure to clean the air side of the after cooler.

• Use a spray bottle mixture of dawn soap and water.
• Run the boat at cruise rpm while spraying the soapy mixture into the air side of the turbo. (remove the air filter.)
• Once the bottle is empty, spray some clean water in it.
• This procedure will clean the compressor blades and remove the oily film clogs the after cooler insert.

What do you think?

 

[DavidM]

I did that spray technique a while before I disassembled the air cooler and cleaned both sides. There was lots of oily soot on the air side that I got off by soaking with Dawn and hitting it with a pressure washer. Don't think the spray technique did much good.

But even if it did, how are you going to pressure test the air cooler before acid flushing. Not testing is risky.

Unfortunately there isn't an easy way. That is why Yanmar and Cummins techs charge roughly $1,000 to do the job for you.

David

 

[lipets]

My plan was to remove the the cooler, connect temp bypass hose between the caps acid wash the system without the cooler.


Take the cooler an have it sonic cleaned and pressure tested.


What about that idea?