Heat Exchanger Maintenance YGM20

[Canonshooternb]

I am looking for some advice on required maintenance for a heat exchanger in a YGM20. The boat has been sailed in salt water in the Northumberland Straight (Eastern Canada) . I recently purchased the boat and do not know the last time the exchanger has been flushed.
What are the steps to clean the exchanger and what solution works best ? The boat is on the hard right now so not sure whether to do it now or wait until the engine can be run up to normal operating temperatures.

 

[Johnb]

I took mine off and to a good radiator shop. They did a great job including cleaning, machining all the sealing surfaces, and painting the outside for $170. The sooner you do it the sooner you will uncover all the problems there may be, including getting new O-rings, gaskets, replacing corroded studs etc. Might plan to replace any hoses and hose clamps removed as part of the job.

 

[kloudie1]

I am assuming 2 GM 20 ?? Coolant side: drain all old coolant and refill with plain water.. run engine until hot then let cool and drain the tap water. do that again, then refill with correct antifreeze mix for your winters. Alternately, this flush can be done by removing the thermostat and backflushing with tap water one time then draining that and refilling with coolant.
Salt water side: get the necessary gaskets and O-rings in hand before opening anything. You will need 2 of 24311-000700 O-rings and 2 of 128695-44070, cover gasket. Drain coolant or do this when you have the coolant drained from previous work. Open the forward end cap carefully; you may have to pry a little but careful not to scratch any sealing surfaces. With the end cap off, look at the inside of the tubes. If they look clean and not like John B's, leave everything alone and put the front cap back on. refill with coolant.. If they are messy looking, pull the back cap off and push out the tube bundle. You can clean it yourself with a pistol cleaning brush, or as John did, take it to a radiator shop .. re-install with the new O-rings and gaskets; refill with coolant..

 

[Ron20324]

I've never had to do the cleaning, but I wonder if vinegar will clean out some of whatever the deposits are?

 

[jssailem]

I am guessing vinegar will just tease debris loose to float around in your system and clog something. The radiator shop uses an acid that will clean your hide - off. The unit needs to be rinsed well when you get it back, before being reassembled.

 

[Ken Cross]

Don't mess with chemicals, just scrub it out. I disassembled ours and used a 22 caliber gun cleaning rod with a brass brush to clean each tube inside. It was pretty easy and in my case I only needed to remove the end caps so the service was done without removing it from the engine. It only took minutes to scrub it out once the two caps were removed. Several of my tubes were plugged, but a piece of heavy wire then the brush did the trick. This is a pretty easy DIY job. Cost for ours cleaning $0.00 plus 2 new "O" rings from Yanmar.

Ken

 

[Canonshooternb]

Don't mess with chemicals, just scrub it out. I disassembled ours and used a 22 caliber gun cleaning rod with a brass brush to clean each tube inside. It was pretty easy and in my case I only needed to remove the end caps so the service was done without removing it from the engine. It only took minutes to scrub it out once the two caps were removed. Several of my tubes were plugged, but a piece of heavy wire then the brush did the trick. This is a pretty easy DIY job. Cost for ours cleaning $0.00 plus 2 new "O" rings from Yanmar.

Ken

The only way to do this is to also disconnect the fuel lines and bleed the entire system after re assemby correct ? No shortcut on that is there

 

[Biobob Catalina 27]

OK, unless that was satire, I am confused, what does the fuel line have to do with the heat exchanger?

 

[Ken Cross]

OK, unless that was satire, I am confused, what does the fuel line have to do with the heat exchanger?

Wrong thread?

 

[MitchM]

note on the heat exchanger job:
1) be sure to order the weird little end gaskets from yan mar . you cannot re use the old ones, they are flimsy and tear when you take the old ones off. have some Form A Gasket ready to help the thin little new ones actually stick in proper place while you are sealing the end caps.

2) when you tighten the end caps do the bolts in alternating fashion 12 o clock, 6 o'clock, 3 o clock 9 o clock etc. a big problem will happen if you tighten all right - side then all left side, resulting in possible leakage..

3) plan to flush your whole cooling system at this time. you'll lose most all coolant when you take off the hoses into the het exchanger even if just to check the end caps.

4) if you are suddenly running too hot, and your coolant level is good, check your raw water pump impeller. if it lost a piece from old age, that piece travels to the heat exchanger where it gets stuck in the end cap and blocks one or more cooling channels. see that there are not little pieces of the raw water pump impeller stuck in the end caps. it sounds hard to believe, but the smallest impeller piece blocking one channel cooling flow was enough to make my yan 2GM20F run hot.

5) you can soak the heat exchanger in vinegar overnight then run pipe cleaners then small diameter copper tubing into the channels to clean them.

6) while you have all the hoses off you might as well replace the thermostat .

 

[Ken13559]

How would I know it's time to clean the HX?

 

[seadaddler]

Very easy to check by taking front and end capes off and you can see real fast
what the inside looks like.
But you will need order new O rings and I had to remove my alternator to get at removing front end cape and I found broken pieces of impeller vanes and some sea water growth but
very miner on my 2007 3YM30.
I will check again and maybe try running some salt away first and than check again or even better check it and than see if salt away really does any good.
Nick