Join the C34 Association Today!
[C34 Home] [C34Tech Notes] [C34 Tech Wiki] [Join!]
Please login or register.
Advanced search  

News:

Pages: [1]   Go Down

Author Topic: exhaust flange leak?  (Read 214 times)

0 Members and 1 Guest are viewing this topic.

waughoo

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 4
  • Posts: 333
    • View Profile
exhaust flange leak?
« on: April 28, 2021, 12:11:59 PM »

I have just completed a full hose replacement (fresh and raw) on my 91 Mk1.5 with the M35.  I still seem to be loosing coolant somewhere, but can find no leaks at any of my hose connections.  I've ordered a new pressure cap and recovery bottle (bought the expensive one from Westerbeke because... why not.  It's FANCY!) and will install that due to it not being present (recovery bottle).  One of the times the temp started to climb and I stopped the engine to check and fill the coolant, as I was adding water, a small amount of steam appeared from the aft end of the exhaust manifold near the flange.  I've read that the gasket back there also seals the coolant passages in the manifold.  Has anyone done this job recently and can share with me how much of a son of a brisket it is and perhaps any useful tips?  I've considered buying an induction bolt heater to allow the removal of the nuts on the flange.  Getting a torch on those will be hard let alone somewhat dangerous.  I'd LOVE to avoid removing the manifold, but I need to solve this leak as it seems to run for about 3 hours before I need to add some more coolant.  Thanks in advance.
Logged
Alex - Seattle, WA
91 mk1.5 #1120
Std rig w/wing keel
Belafonte

Stu Jackson

  • C34IA - Secretary
  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 71
  • Posts: 7926
    • View Profile
Re: exhaust flange leak?
« Reply #1 on: April 28, 2021, 12:26:18 PM »

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

Alex, there are Tips & Tricks in my tech note, regarding both the nuts on the studs and the gasket.
Logged
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Ron Hill

  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 58
  • Posts: 7427
    • View Profile
Re: exhaust flange leak?
« Reply #2 on: April 28, 2021, 02:47:47 PM »

Alex : Look closely at the M35 engine parts as all of the engine flange articles that I've seen (and written) are on the M25 & M25XP engines. 

I just want you to be sure there isn't anything different on your 4 cylinder !?!

A thought

Logged
Ron, Apache #788

KWKloeber

  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 34
  • Posts: 3913
  • "Positive Impact" 1984 C-30 mk-I #3573 trbsfk M-25
    • View Profile
Re: exhaust flange leak?
« Reply #3 on: April 28, 2021, 05:32:21 PM »

Alex

See below for how the exh flange gasket covers the cooling passages behind it in the exh manifold.  Possibly you have a loose flange?
Do you have a sweet odor of coolant in the exhaust?

You might need to install 3 new studs, depending....
IIWMB if they come out easily, I would replace them along with the nuts if there’s any sign of corrosion.
The flange, etc is the same setup as on the 25s.

Before you get into that project, have you pressure tested the Hx? If it’s OEM at that age it’s possible there’s a pinhole leak between the two sides.  When pressure builds in the { edit colored damn you Seri} CLOSED system, coolant gets pushed over to the seawater side and eventually out the exhaust.  Been there, own the Tee shirt.

One way to extend the time is to motor with the pressure cap loose so coolant doesn’t get pushed to the seawater side.

« Last Edit: April 28, 2021, 05:34:58 PM by KWKloeber »
Logged
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Noah

  • Administrator
  • Forum - Master Chief Petty Officer
  • *******
  • Karma: 19
  • Posts: 1956
    • View Profile
Re: exhaust flange leak?
« Reply #4 on: April 28, 2021, 05:43:49 PM »

Ken— Quote: “Do you have a sweet odor of coolant in the exhaust?“ Is that similar to “the smell of napalm in the morning?”  :abd:
Logged
1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig

waughoo

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 4
  • Posts: 333
    • View Profile
Re: exhaust flange leak?
« Reply #5 on: April 28, 2021, 07:26:08 PM »

Before you get into that project, have you pressure tested the Hx? If it’s OEM at that age it’s possible there’s a pinhole leak between the two sides.

The heat exchanger appears to be quite new (looks like the aftermarket 3" sold by catalina direct).  The exhaust manifold on the other hand looks quite rough on the inside.  I havent checked the bolts on the flange yet, but your suggestion to pressure test is a GREAT idea that had escaped my troubleshooting list.  I will add that to my list to check.  Thanks for the reminder.
Logged
Alex - Seattle, WA
91 mk1.5 #1120
Std rig w/wing keel
Belafonte

waughoo

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 4
  • Posts: 333
    • View Profile
Re: exhaust flange leak?
« Reply #6 on: April 28, 2021, 09:02:22 PM »

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

Alex, there are Tips & Tricks in my tech note, regarding both the nuts on the studs and the gasket.

Excellent write up.  Thanks for all the archiving work you do Stu.
Logged
Alex - Seattle, WA
91 mk1.5 #1120
Std rig w/wing keel
Belafonte

waughoo

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 4
  • Posts: 333
    • View Profile
Re: exhaust flange leak?
« Reply #7 on: May 03, 2021, 11:57:56 AM »

So... I ran the boat for 10 hours on Sunday to bring it from Anacortes to her permanent slip in Seattle.  After a shaky start with an air bubble causing hot temps, we managed to run solidly all day at 165 degrees.  I had started to try and clear an air bubbles in the H2O tank lines thinking that's where they were (which there could have been), however, it kept running constantly at 180.  I finally decided after a lack of success with the tank lines, to try the large 7/8" line on the port side of the engine under the exhaust manifold: THAT did it!  There must have been about 2 or three significant bubbles in that line since once cleared there, the engine ran all day with the needle glued to 165.  I was pretty happy after that.  For yesterday's run, I left the cap off the "pressure" setting so it would run at just atmosphere.  We lost no noticible coolant in those 10 hours of running.  Now I need to put the system under pressure and see if it will hold.  I'm going to cross my fingers that it will as I'd LOVE to avoid dealing with that exhaust flange RIGHT at the beginning of the season.  I'll report back.
Logged
Alex - Seattle, WA
91 mk1.5 #1120
Std rig w/wing keel
Belafonte

KWKloeber

  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 34
  • Posts: 3913
  • "Positive Impact" 1984 C-30 mk-I #3573 trbsfk M-25
    • View Profile
Re: exhaust flange leak?
« Reply #8 on: May 03, 2021, 12:30:28 PM »

And the problem with that 7/8” hose is that it’s the return from the Hx to the coolant pump so if you’re burping at the dock and the TStat doesn’t get to open, there’s no flow in it (well, just a trickle thru a 1/8” bypass hole in the flange of the TStat.)


I finally decided after a lack of success with the tank lines, to try the large 7/8" line on the port side of the engine under the exhaust manifold: THAT did it!  There must have been about 2 or three significant bubbles in that line since once cleared there, the engine ran all day with the needle glued to 165.

Logged
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Ron Hill

  • Forum - Master Chief Petty Officer of the Navy
  • ********
  • Karma: 58
  • Posts: 7427
    • View Profile
Re: exhaust flange leak?
« Reply #9 on: May 03, 2021, 02:55:41 PM »

Alex : I just observe that flange ?leak? until you finally figure out if it or the riser is leaking. 

You might squirt some Liquid Wrench/Blaster on the three nuts and start to help let it soak in with the heat of running the engine - just in case you do have to remove that flange!!

I'm not too sure if there is room to get an impact wrench in there (with extensions) if you do have to remove those nuts??

A few thoughts
« Last Edit: May 03, 2021, 02:56:44 PM by Ron Hill »
Logged
Ron, Apache #788

waughoo

  • Forum - Petty Officer 1st Class
  • *****
  • Karma: 4
  • Posts: 333
    • View Profile
Re: exhaust flange leak?
« Reply #10 on: May 03, 2021, 08:43:13 PM »

KW: that explains why it would run at about 1500 at 178ish but any further push would start to make it rise.  There must have been just enough heat soak in the bypass circuit to the tank and a small amount of water flowing through the small air bubble hole to get it to keep itself cool at that load.  I had filled and burped it twice, but that lower hose never presented a problem till that trip.

Ron:  it is possible that there is no leak at the flange.  The pressure test should tell me if I'm okay.  I found a place to rent a pressure tester today (local auto store that basically sells it to you for full price and then lets you return it for a full refund when you're done using it - no loss on their part if you don't return it!) and plan to do that sometime in the coming week.  If it holds 11 to 15lbs for a handful of hours, I will chock this all up to being just a collection of air bubbles that never made it out.  If it won't hold pressure, I suspect the flange gasket is the issue.  To your point of regarding the riser, the previous owner appears to have replaced that in the not too distant past.  Thus, I might have to commit to a sooner than failure exhaust elbow flange gasket replacement.

Thanks all for the thoughts and ideas.
Logged
Alex - Seattle, WA
91 mk1.5 #1120
Std rig w/wing keel
Belafonte
Pages: [1]   Go Up