Heat Exchanger Maintenence

[Mike and Joanne Stimmler]

I am hoping to be able to work on my h/x this weekend, My question is, when I disconnect it how much antifreeze will I loose? Do I need to plug any lines. I will probably be bringing it home to a local radiator shop to get it boiled out so it will be off the boat for 2 weeks.

Thanks,
Mike

[Stu Jackson]

Mike

You'll lose about half of the anti-freeze.  If you have three hands (!), take off the lower port connection to the HX first and stick a wooden plug in it.  Then do the same for the other one.

Conversely, you could look at it as an opportunity to either change out or at least refresh your fresh water system, by letting that half drain out and replace it with a 50/50 mix of anti-freeze and distilled water.  When you take the first line off the HX drain it into a container of some sort that will fit underneath the HX when you crack the hose clamp(s).  Your choice to either reuse or refill.

You may have some difficulty in removing the hose from the barb on the HX if you haven't done so in a long time.  When you replace the hose, slather the barb and the  inside of the hose with Lanocote or wheel bearing grease, so it'll come off easily the next time, but still be held on by the hose clamps.

I suggest you leave the HX itself clamped to the engine until you get the hoses off, or else you'll have to hold onto the moving HX while you're trying to get the hoses off -- another three handed job!

While it's out for those 2 weeks, suggest you use that time to order and get new end caps and gaskets from Sendure.  I spoke with them just last week and ordered a set.  They have 2 kinds, flat bronze ends caps with gaskets and new bolts for ~$34 a pair ($25.68 + S/H for the pair) (part number SK3300C) or the Universal ones with the little ridge at the edge, for somewhat more.  They didn't have Universal ones in stock.  These flat style end caps don't require the middle fiber washer and the gasket is full, rather than the Universal one that has holes in it, looking like the metal part of the HX underneath.   This is for the 3 inch HX (3-1/8 inch end caps).

They answer the phone as "Engines 1" not Sendure.  Ask for Gary or Cal.  Phone # is below, alternate phone is 757-673-7200.

[Mike and Joanne Stimmler]

Thanks, Stu

[Ron Hill]

I'm on my 20th season and have never removed my HX!!  I use Lime-a-Way. 
Disconnect the raw water in hose and fill the HX with Lime-a-Way.  Let it set for and hour, blow that out and fill it again for another hour.  My running temp is 159 degrees.
That's a "hell of a lot easier" than removing it and letting the radiator shop use harsh chemicals on it. 
A thought!   

[Sailing Steve]

I'm not sure that Lime-A-Way can be described as not being harsh...  It is an acid and the directions state not to use on most metals, not that the rad shop would be any less harsh.

Just my $.02

[Jim Price]

I would go with Ron's 20 year record with Lime-Away as not very distructive over taking that contraption off the engine. 

Would point out that on older engines, take note of the condition of the brackets where HX is mounted.  One of my brackets broke on a low hour 1991 model and the HX casing nearly rubbed through where it was resting on the transmission.  Never new this was going on until I had engine check up and mechnic discover while checking back side of engine.  Had to replace with new HX due to the thin condition of the wear point and the cost to repair the bracket was nearly as much as new unit , plus no need to worry about 15 years build up inside.

[Stu Jackson]

The last post gave a good reason to remove the HX, if only to find out if there is any rubbing and deterioration of the shell going on at the bracket.

In the May 2007 Secretary's report in Mainsheet, I wrote:

"Boat Stuff: We keep good records on the upcoming repairs and regular maintenance items that we need to do on Aquavite.  A HX zinc replacement was scheduled for late last fall which I ignored at my own peril.  Not doing that simple five minute job cost me two days of removing and reinstalling the HX because the old zinc was stuck in the hole after it disconnected from the bronze head cap.  Lesson learned: Do it NOW, when it's easy and doesn't require additional or unnecessary work.  I did, however, get to know my newer three inch HX very well, cleaned it inside and out, and assured that the all of the hose clamps are in good shape."

There appear to be some good reasons to remove the HX as a preventative maintenance measure.

Added 5/08:  I also noticed a wear spot.  I placed a folded piece of rubber inner tube from a bicycle tire between the HX and the bracket.  Checked it a year or so later, workin' just fine.

Added 3/25/09:  The inlet from the rw pump to the HX is where the salt deposits can drop out where the cold saltwater meets the hot wet exhaust inside the HX, leading to clogging of the inlet tube on the HX.  Removing and checking it would also help you observe this condition.

[Ron Hill]

Steve : Do what you want, but Lime-a-Way is a household cleaner. 
You don't need heavy rubber gloves like the stuff they use in the radiator shops. 

[RaymondP]

Newbie to diesel engines, but thinking about flushing the heat exchanger/freshwater cooling side of my Universal 25, Catalina 34, 1986 vintage.  Boat is on the hard for the winter.  Has only sailed in fresh water (Great Lakes).

When winterizing i ran the engine with antifreeze to displace the water. Hopefully all good for the spring.  My question is before I return the boat to the water I could apply a similar process, but run Zep/Lime Away/other liquid(??) instead of antifreeze, leave for an hour with the engine off, and then run again with fresh water to flush.   Not looking to inadvertently create problems as temp. settles nicely at 180 degrees F once warm.  Just thinking, given the age of the boat may be a good idea to clean the heat exchanger.  No idea when it was previously cleaned if at all. 

[Jim Hardesty]

My question is before I return the boat to the water I could apply a similar process, but run Zep/Lime Away/other liquid(??) instead of antifreeze, leave for an hour with the engine off, and then run again with fresh water to flush. 

Raymond,
I've also considered a check/maintenance on Shamrock's heat exchanger.  Like you there's never been a problem, so it's never made it to the top of the to-do list.  Also, it's not a common problem with boats in the Great Lakes, at least that I'm aware of.
I wouldn't do it as you suggested.  Reason, the Lime Away would be in the raw water pump.  Don't like that.  Also, there's the zinc anode (in the heat exchanger) to consider.  I admittedly don't know much about the Lime Away so I may be mistaken about that.
If I do some maintenance, think removing the end caps and taking a look would be the way I'd start.  Then go from there.  Maybe just reassemble.  Maybe more.
Just my 2 cents,
Jim

[Ron Hill]

Guys : The way that I use Lime-a-way it never gets into the raw water pump!!!!
 
What I do is disconnect the output line from the pump. Then lift it so it's higher than the HX. Take a small funnel and put it in the output line and slowly fill the funnel with Lime-a-Way.  Do the until the HX is full of Lime-a-way and let it set for about 20 minutes.  The lime-a-way should have done it's job and the you can reconnect that line to the pump and you've cleaned the sediment from the inside of the HX. 

Read the bottle and you'll find that you can use it WITHOUT rubber gloves so it's safe on metal!   

A few thoughts

[KWKloeber]

Newbie to diesel engines, but thinking about flushing the heat exchanger/freshwater cooling side of my Universal 25, Catalina 34, 1986 vintage.  Boat is on the hard for the winter.  Has only sailed in fresh water (Great Lakes).

When winterizing i ran the engine with antifreeze to displace the water. Hopefully all good for the spring.  My question is before I return the boat to the water I could apply a similar process, but run Zep/Lime Away/other liquid(??) instead of antifreeze, leave for an hour with the engine off, and then run again with fresh water to flush.   Not looking to inadvertently create problems as temp. settles nicely at 180 degrees F once warm.  Just thinking, given the age of the boat may be a good idea to clean the heat exchanger.  No idea when it was previously cleaned if at all.

Raymond

I described the annual PM for the Hx in another "recent" posting.   Do a search for it.
It was posted in a topic about winterizing and my comments about the waste of money to, and the logical reasons for not using antifreeze (pink stuff or otherwise) in the seawater cooling system —  instead doing proper annual PM on the Hx, which negates the need for any AF in the seawater system.

Any corrosive cleaner should be used sparingly ( only IF and AS LITTLE as needed to remove what has accumulated inside the Hx tubes.   Rydlime is the safest but is difficult to find except commercially.

The best method is to keep the solution moving (like a very low flow) rather than letting a part "soak" (I could explain why but won't now) and monitor the pH, which will indicate when the removal of accumulation is complete (no more is coming off the surface and now you're down to the base metal.)

I would not be overly concerned about lime a way and an anode, but there's no reason to expose it to a cleaner. 
Zinc (a corrosion preventive coating for nuts/bolts) is less reactive to dilute HCl than magnesium (Jim's) but it's not like a large anode is going to melt away — but still, it's unnecessary to expose it. 

Yes, if the closed (FRESHwater) system hasn't been flushed/renewed that's important ( FRESHwater system is closed, the SEAwater system is open (kind of a misnomer if the boat is in freshwater, but "sea water" doesn't mean SALT water.))

[Ron Hill]

Ray : That HX may NEVER have been pulled or cleaned.  I'd remove it and take it home and take the end caps off and check the insides. Get yourself a couple of new end caps & gaskets, clean out the inside and pressure check it.  Then you'll be go to go for ? number of years, because who knows how many broken Zns are on the inside!!

On removing old hoses, what I do is hit them with a heat gun and they pull off easily.  When reinstalling I use the heat gun again with some dish washing soap so they slide right on!!   

A few thoughts

[KWKloeber]

  Then you'll be go to go for ? number of years, because who knows how many broken Zns are on the inside!!

A very precise number would be zero.  Ron, how can that occur?  Looking at the flow thru the Hx on our engines,
(here:)  https://groups.io/g/Catalina30/wiki/9626#Coolant-flow-on-earlier-engines-28e-g-2C-M-252FXP2FXPA29
on the seawater side, there's no flow "backward" into the tubes.

As far as see the only place a piece of anode can end up is the "chamber" between the intermediate plate (that the tubes are brazed to) and the end cap, or it got expelled and went to the vented loop or muffler.

[Ron Hill]

Ray : Take your HX off and take it home!!  Like I mentioned take the end caps OFF and see what junk come out!!  I've seen Zns disintegrate and crumble. Maybe that's unique to the Chesapeake Bay salt water?? 

A thought