Heat Exchanger Maintenance Question.

[er9]

If all i want to do is pull the end plates to check for blockage and replace the zinc, all i have to do is pull the raw water inflow hose to the exchanger and drain it before pulling the end plates correct? Iv'e never done this before and so long as i'm not removing it from the engine im assuming i dont have to touch the fresh water system as its sealed off inside the heat exchanger.

[Orion Jim]

You have it right. If this engine is new to you it would be worth removing and descaling the unit.

[Tillsbury]

Might pay to check your manual though. Removing the heat exchanger for cleaning/maintenance it clearly tells me to drain both the seawater and coolant circuits on my Volvo. Maybe it’s telling me porkies though. Surely this is part of both systems? On ones I’ve done this to the seawater is running down the internal pipes and the entire thing is full of coolant that runs over the outside of the pipes.

[Dooglas]

A quick look on-line showed 3 1980 Mariner 36 sailboats for sale. One had a Volvo D1-30 engine, one a Universal M32 engine, and one a Yanmar 3GM. Seems like information about the engine in question would be needed for anyone to tell you much about opening and descaling the heat exchanger.

[er9]

Originally Posted by Dooglas

A quick look on-line showed 3 1980 Mariner 36 sailboats for sale. One had a Volvo D1-30 engine, one a Universal M32 engine, and one a Yanmar 3GM. Seems like information about the engine in question would be needed for anyone to tell you much about opening and descaling the heat exchanger.

thanks. its a universal 5432 and has a westerbeke 3" heat exchanger. I found a little more info and decided to give it a go. disconnected hose from water pump">raw water pump and dipped it below the heat exchanger to drain. only sea water came out, pulled the one end cap i could access and it didn't look pretty.

i think i'm going to pull it next weekend. i found another problem with the fresh water system when i was poking around. i had noticed last time we took the boat out (6 months ago) the antifreeze overflow jug kept slowly getting lower. today i noticed it was empty and antifreeze had leaked out of what appears to be the two upper bolts of the fresh water pump.

after the heat exchanger is taken care of i'm going to need to take a closer look at the water pump and thhe fresh water side of the cooling system. i am thinking i should flush the cooling system and check thermostat etc...possibly replace the pump but will wait till i get to that point.

[Mikado]

Originally Posted by er9

If all i want to do is pull the end plates to check for blockage and replace the zinc, all i have to do is pull the raw water inflow hose to the exchanger and drain it before pulling the end plates correct? Iv'e never done this before and so long as i'm not removing it from the engine im assuming i dont have to touch the fresh water system as its sealed off inside the heat exchanger.

Last month I removed my Westerbeke diesel generator heat exchanger, removed both end plates and took it to the local radiator shop and had it hot tanked and rodded out. Came back looking and working like new. $100 well spent.

[er9]

Originally Posted by Mikado

Last month I removed my Westerbeke diesel generator heat exchanger, removed both end plates and took it to the local radiator shop and had it hot tanked and rodded out. Came back looking and working like new. $100 well spent.

Thanks good to know. that sounds much better than $350 for a new one.

[jmschmidt]

I don't know how yours is set up by you need to drain the coolant as well since it is in there somewhere. We don't have a lot of real crud living in the ocean in Hawaii so I've always been able rod the bronze core out with a small hardwood dowel.

[Diesel Bill]

The way I clean the tubes is remove end cap and use 1/8" brass brazing rod to punch through each tube. Some times the end plate is coated with whitish mineral (calcified) and needs to be removed first. The antifreeze and fresh coolant can stay on the outside of the tubes, and is non the less not affected. If it's really fouled I circulate hot water and acid. (pool acid) for a little while. 10 -30 minutes usually is enough. Flush with raw water after reassembly. Really brings the engine temp back to specs if every thing else is working correctly.

[Panacea2183]

Originally Posted by er9

If all i want to do is pull the end plates to check for blockage and replace the zinc, all i have to do is pull the raw water inflow hose to the exchanger and drain it before pulling the end plates correct? Iv'e never done this before and so long as i'm not removing it from the engine im assuming i dont have to touch the fresh water system as its sealed off inside the heat exchanger.

Correct!
If they need to be cleaned (most likely, I flush mine every 2 years)
Do yourself a favor and DO NOT remove them.
I’ve used Barnacle Buster for years on engine heat exchangers and A/C units.
Easy peasy and SOO much less labor, plus it gets every thing in whole loop clean.
It will dissolve all the Zincs in the loop so plan on replacing them after the flush.

I read so many suggestions on removing the exchanger and taking to a radiator shop. Waste of time and money!
Look it up and watch the videos, this stuff works.
I have no relationship to this company, just a happy customer. (12+ years)
PS: when you remove your end caps, plan on replacing the gaskets (Barnacle Buster will not harm them) but they very rarely can be used over with satisfactory results.

[Quadrille in JB]

+1for Barnacle Bustier
I use it on both my enigine and AC heat exchanger

[er9]

Originally Posted by Panacea2183

Correct!
If they need to be cleaned (most likely, I flush mine every 2 years)
Do yourself a favor and DO NOT remove them.
I’ve used Barnacle Buster for years on engine heat exchangers and A/C units.
Easy peasy and SOO much less labor, plus it gets every thing in whole loop clean.
It will dissolve all the Zincs in the loop so plan on replacing them after the flush.

I read so many suggestions on removing the exchanger and taking to a radiator shop. Waste of time and money!
Look it up and watch the videos, this stuff works.
I have no relationship to this company, just a happy customer. (12+ years)
PS: when you remove your end caps, plan on replacing the gaskets (Barnacle Buster will not harm them) but they very rarely can be used over with satisfactory results.

interesting I will take a look at that. it would be nice if i could leave it in as it's hard to reach the bolts without inventing some new yoga move.

owning a boat has been great for my flexibility health.

[Tillsbury]

Only downside is that chemicals won't remove the bits of shredded impeller left there by the previous owners, so removal is not a bad idea every now and then...

[Pete7]

On a previous boat I chucked it in the dishwasher along with the turbo intercooler when the wife was out as a starting point before cleaning the rest by hand. Got away with it as well, for a couple of years

[Bean Counter]

Used Barnacle buster on our Onan generator, closed the through hull, filled the strainer with it, primed for a couple of seconds so the solution entered the heat exchanger, let it sit. Open through hull ,started and let it run for 5 minutes, heat exchanger was clean, changed the zinc. I think I will try this on the Yanmars when the time comes.