cleaning heat exchanger problem

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cleaning heat exchanger problem

Postby Oliver » Mon Oct 07, 2019 7:10 pm

I had an overheating problem above 1,600 rpm. on the Stbd Ford Lehman.Flow of exhaust water is noticeably less that port engine. Worked through cooling system to heat exchanger. End cap only comes off on the end opposite the zinc. How can I inspect and clean it out without being able to have both ends open?

2. I can't get the cap on the the tank to seal. Water blows out instead of going to the overflow bottle. I tried bending the prongs. Got tighter fitting but no fix.
Oliver
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Re: cleaning heat exchanger problem

Postby Richard Werner » Mon Oct 07, 2019 10:28 pm

Make sure that you have bled the cooling system.
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Re: cleaning heat exchanger problem

Postby Oliver » Tue Oct 08, 2019 9:17 am

Of course. I have owned the boat for 14 years.
Oliver

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Re: update cleaning heat exchanger problem

Postby Oliver » Tue Oct 08, 2019 3:25 pm

When I went to drain the heat exchanger the square headed plug disintegrated! Does anybody have any tips for removing the two bolts? I don't think I can get a socket on the outboard bolt. When I get it off I am going to carefully cut off the other end. If all goes well I will silver solder it back on if the exchanger is worth saving. At $700 or so I can't afford to replace it right now.
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Re: cleaning heat exchanger problem

Postby Tom Overs » Thu Oct 24, 2019 4:24 am

Oliver.....
Problem one, if you remove the heat exchanger, you can clean it out with kettle descaler, you will also be able to check the condition of the tubes.

Problem two, check the thermostat isn't stuck.
The two systems are separate and from what you have said I think you may have a head gasket problem. Easy check is to remove the pressure cap and fill the header tank, start the engine and if you have air bubbles coming up its more than likely it's head gasket.
God luck with this.
Tom.
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Re: cleaning heat exchanger problem

Postby StevenD » Sat Oct 26, 2019 8:59 am

I know this sounds stupid, but have you checked the hose and thru-hull leading to the strainer for growth or weeds sucked in? Is there a strainer over the thru-hull? Decreased flow starts there. I've done a lot of unnecessary work to find stupid things.
Steve
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Re: cleaning heat exchanger problem maybe solved

Postby Oliver » Mon Oct 28, 2019 12:15 pm

Here's an update. Sent heat exchanger out to be pressure tested. Turns out there was a hairline crack in the inlet. I suspect when everything warmed up and higher rpm and with greater water flow it started loosing coolant which explained the coolant in the engine pan. I had assumed that came from the leaking cap. Once again a good reminder of assumptions.

2. Removed raw water pump and had it rebuilt. Tech found pieces of impeller in the outlet which had been overlooked. In the 14 years I have owned the boat I never had an impeller failure so this was from long ago with the PO.
3. Have removes thermostat-tests good, Removed oil coolers and hoses. All good. Good flow from through hull through Groco strainer.

Putting it all back together. Fingers crossed.
Oliver

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Re: cleaning heat exchanger problem

Postby Cruising » Mon Oct 28, 2019 3:36 pm

When it comes to heat exchangers my mantra is replace rather than fix.
I feel this is a throw away item.
Lenco on Long Island will fabricate a form/fit/functionality identical heat exchanger for very little. I have found them to be an excellent resource.
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Re: cleaning heat exchanger problem

Postby FrugalWife » Fri Nov 01, 2019 9:07 am

I would agree also - replace. One of the last things you need (or want) to go wrong is an overheating situation. Likely it will happen when least wanted. Although I consider a heat exchanger to be expensive it is still worth spending to replace. IMHO.
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Re: cleaning heat exchanger problem

Postby Charlie0 » Fri Nov 01, 2019 9:59 am

Just replaced mine. (3) They were known to be 10 years old. Not sure on the hours. Might have been a little premature but I know where I stand. Kept the engine exchanger as a spare as it is the most expensive.
Charlie O
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