Heat Exchanger symptoms of failure

[Lance Jones]

Howdy all,
It has been ages since my last post. We have been working hard bringing our Wellington 44 to sea worthy status. However, we were relocating to a new marina the other night and at the end of the 10 mile motor/sail, I was powering down. The cabin filled with a black, sooty smoke. The interior was coated with the stuff. Engine was running normally and all of the levels were as they should be. I continued to my dock (3 minutes).

In the day light, I inspected the under sink engine access on the port side head. It was sooty. The muffler looked to be streaked with a black fluid. I read this http://c34.org/bbs/index.php/topic,8137.msg56798.html?PHPSESSID=807153e15047426572180aed75d08962#msg56798 but, it doesn't seem to match. Any suggestions before I pay for something I can do myself?

Thanks in advance!

[mark_53]

Did you run the engine while docked to see where the smoke is coming from?  I'd check your exhaust riser. 
When the heat ex gives out, you will overheat with steam coming out the exhaust.

[Lance Jones]

No I did not. That was my next step. I'll be doing that when I replace my thermostat and pump impeller. Thanks for the hint.

[Ron Hill]

Lance : Mark is correct, the HX has nothing other than using its exhaust (heated) raw water which is usually injected into the exhaust gases to cool the exhaust gasses down.

Your first indication of a HX failure will be the temp gage goes shy-hi!!

Run the engine and look at the exhaust manifold, the attached riser, raw water connection and the muffler connections.

What kind of an engine does your Wellington 44 have?

A few thoughts

[Lance Jones]

This issue is with my C-34. The Wellington has a 85hp Perkins 4-236

[KWKloeber]

Lance

My first suspicion is either that your:

1. Aqualift muffler has failed someplace (typically at the fiberglass inlet nipple or along a joint at the base) or
2. Exhaust riser to muffler hose has failed or loosened, or
3. Water injection wye on the Exhaust riser has failed, or
4. Riser has failed elsewhere.

Due to the need to build up back pressure to "pump" the exhaust/cooling water up and out, any of the above will cause exhaust gas and carbon-laden cooling water to leak.

Without more detail on the engine, riser, muffler, maintenance history, etc., I can't say which of above (or other) is the more likely culprit.

Whether you can fix it yourself depends on your wherewithal.  But there is nothing in the above that is a "mechanic must do."

Why are you replacing the thermostat?

Put your engine info in your forum profile.  Help us to help you.


ken

[Lance Jones]

Thanks for the reply.
It is an M-25XP. After 8+ years on the forum and preparing to sell her, no real push to add it.
The thermostat has been sticking a bit lately. So, with an eye on selling her, a new one is in order along with annual water impeller change.

[Stu Jackson]

Lance,

This might help:

http://c34.org/muffler-exhaust-riser-replacement-2015/

Sounds like a busted riser.  There's a mention of my earlier article on riser replacement in the link above, as well as to Ron's writeups.

They explain what's necessary for you to be able to decide if you can or want to do it.

Good luck, almost all of us have managed.

[Lance Jones]

Thanks Stu!
Great article.

[J_Sail]

Stu,
The link http://c34.org/muffler-exhaust-riser-replacement-2015/
came up as password-protected for me just now. Is that intentional?
Jeremy

P.S. I hope the NW is treating you well. I enjoyed our in-person chat on your boat long ago in Alameda.

[Stu Jackson]

The Tech Notes Online are limited to access by C34IA members.

I, too, enjoyed our conversation.  It has been just a year since we arrived here on Aquavite and a great summer of cruising and learning new places, as well as meeting friends old & new.

[Roland Gendreau]

If the riser has failed and you elect to do the replacement, there are helpful posts on the subject.  I replaced mine last year and posted the details at that time.

[KWKloeber]

Lance did you investigate further?

If you need to replace the muffler as Roland says, and/or depending on the condition of the Aqualift, there may be another option for your XP that has not (yet?) been written up.  This summer "we" replaced the exhaust on #333 (M-25XPB) with the water cooled riser and a new muffler.  I use "we" very loosely because Bill did all the physical work and measuring.  I only provided a CAD mock up to physically try in place and verified w/ CAD that it would all fit and work.

Ken

A couple pix of the 99 & 44/100% completed install:

[scgunner]

     Since this thread is titled "Heat Exchanger symptoms of failure" I'll share  my experience on the subject. I was motoring along and unbeknownst to me the tubes in the exchanger developed a leak do to corrosion, the result was the coolant was sucked out through the raw water system which pegged the temp gauge. I was able to crawl back to the slip by pouring water into the coolant fill. When I checked the zinc it was completely gone, up until then I didn't even know it had a zinc there.
     Moral of the story, check your zincs those replacement heat exchangers are expensive little suckers.

[KWKloeber]

Typically it starts out as a pinhole who's only symptom is a slow loss of engine coolant, and may not be noticed until the reservoir tank is empty.  Or the tank may not empty much if air/sea water (instead of coolant from the reservoir) is drawn back into the closed system thru the pinhole as the engine cools.  So, mates/mate-ettes if your coolant seems to be going down, don't just keep refilling the overflow -- investigate the cause.  The loss of coolant can be somewhat overcome for a short period by running with a loose pressure cap (it's the 13 psi developed in the closed system that forces coolant out thru the Hx to the muffler/exhaust.)

For those who don't know exactly what/how your pressure cap/reservoir-overflow works, a good explanation:

https://youtu.be/OPKaFcOwemI


k