Heat Exchanger Replacement ?

[kb79]

I'm getting ready to go on a two year cruise, and am doing some engine work - just minor maintenance stuff.

I had the engine surveyed before I bought the boat, and after addressing all the findings, I had the mechanic back to take a look over my work.

On this second look, he recommended replacing the heat exchanger. It's working fine, but he thought it landed in the category of periodic replacement, and felt that it's something he'd replace on an older boat before heading off on a trip that ambitious.

Do you guys agree?

Is there something I can do to assess the condition of the heat exchanger before just replacing it?

The boat's 26 years old, but I can tell it's not the original heat exchanger (doesn't perfectly match the pictures in the service manual). I have no idea how old it is though. It's a Westerbeke 33 engine if that matters...

[SkiprJohn]

I'm not certain about Westerbeke but for information about Perkins which is a close match you might want to explore the "overheating" problems in some earlier threads. Just type in overheating in the search engine after my signature and I'm certain you'll have some interesting reading.
I'm of the school that says "if it isn't broke, don't fix it."
kind regards,

[foggysail]

Sure, replacement most times gives a better result. Personally, I would see if I could remove the exchanger along with the end covers (if possible) and use a rod to clean the tubes. I did that on my 20 year old power boat about 3 years ago. Things are just fine

[capt_douglas]

The heat exchanger, to me, is one of those single point failures that can prevent operation of the engine. I don't know the cost but you might consider taking the old one off and getting it cleaned and inspected/evaluated. When I cruised, and will be heading out again, I carried a spare, used but in good condition, heat exchanger. I never used it (I tend to never break things I carry as spares.) though.

As much as I too agree in the 'ain't broke, don't fix it' mantra, you might consider finding a good quality used one instead of a new one. I've always placed high value in items that could prevent the engine from running (like raw water impellers, belts, etc).

[Hannah on 'Rita T']

Put on a new one, boil out the old one and keep it as a spare.

[Minggat]

Originally Posted by HannahGardner

Put on a new one, boil out the old one and keep it as a spare.

That's sound advise. Short of that, at least remove the one you've got and take it into a radiator shop for assesment/repair (boil out the old one). Then proceed from there.

[kb79]

thanks guys

[Tempest245]

If it's any help to your decision making process. The Replacement heat exchanger to my WB 27 was $400. I'm sure it was the original..23 years old at the time..which is pretty good for periodic maintenance.

How do the fittings look, are they corroded ? Has the zinc been changed regularly? How is the water flow? Have you changed out the hoses and clamps?

[kb79]

there's pretty good corrosion on both ends of the heat exchanger, but not the fittings. water flow looks good. hoses and clamps have been changed. i can't speak for the zincs (since i've only owned the boat for a year or so), but the first thing i did when we bought it was to swap the zinc...

sounds like i'll be buying a new one. i can get an aftermarket part for about $365. i'm not wild about it, but it seems prudent. my mechanic has been pretty spot on so far.

[Doodles]

Originally Posted by Minggat

That's sound advise. Short of that, at least remove the one you've got and take it into a radiator shop for assesment/repair (boil out the old one). Then proceed from there.

That's what we had to do solve an overheating problem on our Niagara (Westerbeke). It came back looking brand new inside. Don't forget to get new gaskets for the ends.

[osirissail]

Originally Posted by HannahGardner

Put on a new one, boil out the old one and keep it as a spare.

That is the best advice if you are heading out to sea for few years. Heat exchangers wear out mainly by electrolysis since they are made mainly of copper while the rest of the engine is steel. Zinc replacement in a heat exchanger is one of those easily forgotten tasks.
- - You can remove, clean the old heat exchanger and then pressure test it yourself. Get two pieces of garden hose, 2 hose clamps and a pair of vise grips. Hook up the garden hose from your home water spigot to one of the inlets to the heat exchanger, preferably the raw water side. Then hook up a short piece of garden hose to the outlet of the same side of the heat exchanger. turn on your home water spigot and use the vise gripes to close off the outflow piece of garden hose. Most home water supply is about 35-45 psi which the heat exchanger should handle easily. If you notice water coming out of the other side of the heat exchanger then you have worn out and leaking tubes inside the heat exchanger and it is a "throw-away."
- - You can get into a world of trouble if the heat exchanger tubes fail and allow raw water to enter the coolant galleries of engine cylinder heat, coolant pump, etc. So having a new and a spare for a long cruise away from a convenient source of replacements is a very good idea.

[boatrips]

I had an overheating Perkins 4-108 last month on my boat that is in charter service. I had to make it ready for the next charterer who was to arrive in three days, and I remembered the experience of a person I knew many years ago who was a chemist and had a boat with a diesel engine that was overheating.

He told me to purchase a quart of muratic acid, and add it to about 3 or 4 gallons of fresh water in a tall waste basket. Then turn off the sea water thru hull valve, and remove the hose to the engine from that valve. This hose was extended with a coupling and placed into the bottom of the waste basket with the acid-water mixture. He said to start the engine and run it until the acid water mixture was almost gone, then reconnected the hose to the sea water valve and start the engine again.

Heating problem solved.

OK, here's his as a chemist's explaination: It seems that the muratic acid mixture will eat up all of the salt in the exchanger and return it to it's original condition, as long as you reconnect the hose immediately and run the cooling water through the engine to rinse out the heat exchanger again.
His thoughts were that if the heat exchanger was no good anyway the acid-water treatment would bring it to the front with almost no time or money spent.

My engine was showing a reading on the temp guage of over 200 degrees before and down to about 140 degrees after the procedure with no leaks anywhere in the system, and the increased water flow out the exhaust was an impressive noticable change.

My boat was ready in time for the charterer to step aboard.

I would recommend that this might be an alternative to replacement of the heat exchanger by this reconditioning procedure.

Good Luck.

Jim

[Minggat]

muratic acid, aka HCL, aka -hydrochloric acid is death to a lot of things. Salt probably is the least of the buildup in a heat exchanger. Most likely calcium buildup. Spill a little pool acid on concrete and watch it foam. Stay clear of the fumes.

[delmarrey]

It is practically impossible to give advise on something one can not see. If your Mechanic has given you good service and he says you need a new exchanger, then I would go with that and change it out.

Old boats can not be second guessed. I know I have one. Everything on this boat has been either rebuilt or replaced since 1999 except for the hull and safety lines/rails.

[osirissail]

Muriatic acid is the sailors friend, but also it can be your worst enemy. It does "eat" away calcium deposits, aka barnacles and other sea life that like to attach themselves to your vessel and its innards. However, it can do a number on metal parts so you have to be very careful about duration and concentration used. Marine air conditioning outfits use it to circulate through the closed heat exchanger tubing to clean out scale and calcium deposits.