Heat exchanger leaking

[Steph]

After process of elimination to find the cause of my overheating engine, my heat exchanger has an internal leak! I brought it home to rinse out with vinegar and confirmed (with food coloring) that the raw water side is leaking from the "thin tubes" with the anti-freeze side. This would explain the overheating, right? Interestingly, my antifreeze levels were never low. Can this be repaired or is it time for a new heat exchanger? Thanks!

 

[Ron20324]

It would depend if it is a "tube" leaking, or a solder job at the end of a tube.

I was at your ex-Wet Dog Cafe today. They did a nice job with the remodel.

 

[Steph]

not end

Thanks Ron, but it's not the casing. When I put water into the "raw water side", it leaks into the antifreeze or "internal" side. One or more of the fine tubes is leaking. (haven't eaten at Cafe yet). Thanks. Steph

 

[kloudie1]

Rebuilding or replacing the tube bundle is the right answer.. If you can find a place that re-tubes heat exchanger bundles commercially, they can probably do the work for fewer dollars than buying one from the engine folks.. Look under "Heat Exchangers"in yellow pages and look for a place that advertizes repair.. call 'em and tell them the length of the bundle and the diameter of the little tubes.. they probably can give you an estimate pretty quickly.. Do talk to the engine folks as well since sometimes their price for the part (surprisingly) can be lower than repair. Let us know what ya find.. Good Luck

 

[Snotter]

Help me to understand: your engine was overheating because the raw water was mixing with the freshwater? How would that cause the engine to overheat? I would think that that would cause the engine to run cooler than it should?

Was the freshwater system chronically low (caused by the HX leak)?
Was the HX tubes clogged up (possibly from bits of old rubber impellers)?

 

[Steph]

interestingly the antifreeze level stayed normal but water flow was down thru the exchanger. That 's why i checked it and found the leak(s). I would have thought that the antifreeze level would drop since it's a higher pressure than the raw water side. Everything else seems to look ok. It's not the casing that 's leaking but the little tubes within the exchanger. Steph

 

[RichH]

If you can identify the exact tube that is leaking .... the standard 'industry' temporary fix is to drive/hammer wooden tapered plugs into the 'tube sheet' (ends of the tube) thus totally blocking the errant tube.
If the tube 'ends' are loose/leaking in the 'tubesheet' - the drilled plate that holds the tubes in place - then the tube has to be replaced / re-welded / or 're-rolled' -- easily done by a 'boiler shop' or heat exchanger shop. The 'isolation' of a single tube will not adversely affect the heat transfer.

Most Heat Exchangers can easily be 'rebuilt' / repaired .... much cheaper and just as reliable as 'new'. Repair done by 'boiler shop' or 'heat exchanger' shop.

BTW - take the exhaust manifold along with you to the Hx shop .... to be pressure tested to validate the presence (or not) of internal 'pin holes' in the exhaust manifold casting. If your exhaust manifold has developed pin holes between the 'gas side' and the 'water side' of the manifold you can have the exact same 'symptoms' .... and the water will be 'sucked back' into the combustion chamber when the engine is shut down, etc.