Thread Tools Search this Thread Display Modes
Old 06-26-2011, 02:19 PM   #1
Senior Member
RED's Avatar
Join Date: Jun 2008
Posts: 182
Heat exchanger question

I just replaced raw water impellers, and one of the impellers was badly damaged.* So I pulled the raw water bonnet off the heat exchanger to pick out the parts of the impeller.* I put everything back together and ran the engine (after replacing belts, filters and impeller) to bring it up to temp and an all around check.* I noticed a slight weep at the base of the heat exchanger bonnet, and assumed I needed to replace the gasket, since I had opened it up.* When I took the bonnet off, I had engine coolant coming out into the raw water side.

I pulled the heat exchanger and took it to a condenser shop.* They disassembled the tube bundle from the exchanger and pressure tested the tube bundle, which passed the test.* The technician noted that the O rings for the tube bundles look flat, so the plan now is to reassemble and pressure test the entire unit.

While the heat exchanger is in the shop, I did a "leak down" test on the other engine - filled the expanson tank to brim full, ran the engine up to about 2/3 throttle fro about half an hour to get up to temp, and then shut down.* At the end, lots of pressure in the expansion tank, no loss of fluid.* So, based on this rudimentary test, it looks like the second system is good.

One added note; this has been a fresh water boat for its service life; I purchased it on Lake Michigan, and have been cruising the Columbia River myself.

So the question is what to do.* Am I approaching end of life (its a 1994 boat), or just seeing bad seals, perhaps from the 6 month winter dry layups.

A replacement unit is $2 boat units, and significantly about a week away, which is getting close to my planned departure for the offshore run to Canada.

Any thoughts, advice?


RED is offline   Reply With Quote
Old 06-26-2011, 11:04 PM   #2
Edelweiss's Avatar
City: PNW
Country: USA
Vessel Model: 1976 Californian Tricabin LRC
Join Date: May 2011
Posts: 1,860
RE: Heat exchanger question

Sound like a seal problem. *It doesn't take much wear on an O ring to allow a leak under pressure which will contaminate the coolant side of the system. *But you should also mention your engine make and which cooling system. *Maybe someone who has your setup and has some knowledge of this problem. *

Mine are 6.354 Perkins and the tube bundle is inside of a bronze pipe , they use a large flat rubber washer and a plate with a bolt in the center on both ends of the pipe to seal and keep the two systems seperate and they are prone to leaking over time.*

Also you mention you are going to Canada; I buy all my heat exchangers from The Manifold Wearhouse. *They are a good source, reasonably priced and they are located in Vancouver, BC. They also have a website to order from online for quick service.*

Good luck


Edelweiss is offline   Reply With Quote
Old 06-26-2011, 11:18 PM   #3
City: Carefree, Arizona
Country: usa
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 8,877
RE: Heat exchanger question

On many engines, a bad seal on a HX will not leak coolant, only raw water. If you damaged your RW pump impeller, does this mean overheating occurred? Coolant may be coming from elsewhere if so.

For decades, my mantra has been impellers*replaced every 18 months. They look good when they come out, just as they should. Catch them early and you'll never be picking out rubber parts, or worse. After 17 years, a new tube bundle is not out of the question. If the old one tests out good, you have a spare. But first, find the source of the coolant leak.
sunchaser is offline   Reply With Quote
Old 06-27-2011, 05:31 AM   #4
TF Site Team
Larry M's Avatar
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 9,156
RE: Heat exchanger question

We have the Ford Lehman SP135.* We were told that the heat*exchanger*should be replaced every 15 to 20 years regardless of how it tests.* We installed a SeaKamp*for less than $800.00.***
Larry M is online now   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
heat exchanger KJ Power Systems 21 01-09-2012 10:24 AM
heat exchanger (good source) tomtomterrific Power Systems 7 05-02-2011 05:41 AM
Heat exchanger maintenance Per Power Systems 1 03-24-2011 03:34 PM
Heat Exchanger Wannabe Power Systems 6 02-07-2011 03:30 PM
Heat Exchanger Question Forkliftt Power Systems 18 11-10-2007 11:52 AM

All times are GMT -5. The time now is 10:32 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012