Over the past several months I began to notice my engine temp (M25 Universal) was running at around 160' (note: I'm not sure if the temp gauge is accurate?) when with the engine at around 2000 rpm... When I pushed the engine a little harder the temp gauge jumped up to around 180'. When I ran the engine at this rpm, with the noted increase in temp on the temp gauge, I could smell the engine getting hot. Now I know "If it aint broken don't fix it" but what fun would that be?
A good project is always worth the gamble. So, off I went on my Heat Exchanger project. I was planning on removing the HE, cleaning the unit with a mild solution of muriatic acid, and then replacing the unit... Prior to beginning I spent a few hours on the computer doing some DIY research.
I drained the engine block radiator fluid, removed the hoses and then removed the Heat Exchanger. It's simple to remove. It's only held onto the engine bracket with two SS clamps. This is when the fun began. Upon removing the HE and making my first inspection I found the Previous Owner had welded the port side of the HE shut, the side where the pencil zinc is located. One can only guess why the PO did this??? I removed the round starboard cap which is held on with one bolt and inspected the cooling tubes. I was surprised that all but two tubes where clean bright copper. The problem was who knew what the other end looked like?
My research from a few days prior found that Universal had sent a notice out sometime after my boat was built and recommended the 2” HE be replaced with a 3" model for better cooling.
A mechanic I use for more difficult engine problems once told me prior to me spending a few extra dollars on a repair that I did not want to tackle, “Imagine being out on the SF Bay motoring. The tide is strong and there is no wind. You are approaching the Bay Bridge and suddenly your engine stops and one of the bridge piers is coming into view. You are being carried by a really strong tide heading towards the pier. At that point how are you going to explain why you didn’t fix the engine??? “Happy wife…happy life!”
I purchased a new 3" HE from a local shop and returned to my boat with the HE, a set of new hoses and SS clamps in hand.
Replacing the unit was simple enough. I resecured the HE onto the original HE engine bracket with larger and brand new SS clamps. Now the fun began. The PO???? What was he thinking? I discovered the 1/2" hose the PO had used to connect the HE to the water pump should have been a 5/8” hose. The PO had forced the smaller ½” hose onto a larger fitting??? The PO also used a 1" hose to connect the engine coolant reservoir to the HE. The only problem the fitting the HE is 7/8". The PO simply put the 1" hose over the 5/8" fitting and clamped away. And did I mention none of the hoses had wire in them to prevent potential collapse???
My solution to the reduction was now going to be another project. The one thing I found that helped was the reduction used from the 1” coolant pump fitting to the 7/8” hose that connected to the HE. The PO had used a simple copper ¾” 90’ elbow. I believe the correct term is a street elbow, where one end is used to fit a ¾” copper pipe and the other end is designed to fit into a ¾” coupling. Anyway one end is a perfect fit for a the 1” pump hose and the other end fits the 7/8” hose. Connecting the coolant reservoir to the HE was another problem. I found that a ¾” brass nipple fits the 1” hose and the other end of a ¾” MIP X S copper fitting fits the 7/8” hose. A little Teflon tape on the nipple threads, screw it into the copper fitting and there you go, a simple reducer.
With the HE clamped to the engine and all of the hoses connected I filled the reservoir with new coolant, warmed up the engine, burped the air bubbles and ran the engine with the prop in gear. With the engine at 2000 rpm the gauge now reads around 155’. Bumping the engine up to almost full throttle the gauge didn’t budge from the 155’ mark. I ran the engine at this higher rpm for about ten minutes without a temp spike or the hot engine smell. Project completed!
I believe my temp gauge is not on the mark. I will be testing it out soon for another project. The engine thermostat is recently new and is the correct one for the M25 Universal.
Now all I have to do is go for the sea trial which will be in a few days…
Chris Stewart
S/V "24~7"
1984 Catalina 36 Tall
Hull #251 M25
(SF Bay) Alameda, CA
Thanks for sharing that. If you took photos of the process, it would be a great JibSheet article.
Did you?
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/
Chris, it is ironic that you would post this today. I am planning on removing my heat exchanger this weekend, cleaning it out and then reinstalling it. I found a web site where a gentleman who owns a 36 gave a very thorogh expaination of how he completed the project. I will check on my other laptop and post the URL. It is great because he has about a dozen pictures. I will look for it tonight.
Glenn Druhot
Carpe Diem
New Bern, NC
35* 6' 10" N / 77* 2' 30" W
2001 C36, Hull #1965
Std Rig; Wing Keel; M35B
This is the URL that I was alluding to that describes how to disassemble, clean and reinstall the heat exchanger. It is excellent and the photography illustrates all of the pieces of the HX.
[B][I][COLOR="Navy"]http://www.pbase.com/mainecrusing/boat_projects[/COLOR][/I][/B]
Glenn Druhot
Carpe Diem
New Bern, NC
35* 6' 10" N / 77* 2' 30" W
2001 C36, Hull #1965
Std Rig; Wing Keel; M35B
Chris, good work and good description. I would add to your work:
1. Install a method of vibration isolation between the bracket and the HX. I took a piece of bicycle inner tube: [url]http://c34.org/bbs/index.php/topic,5736.0.html[/url] I'd found the HX shell rubbing too much against the bracket.
2. Check the black hose from the fresh water circulating pump carefully. The part of that 90 black rubber hose can rub against the front of the engine (gear cover housing) and the hole will be, guess where: you can't see it. My old back hose had almost rubbed all the way through.
Don't sweat the temperature. You're probably running a 160 thermostat. I bought new thermostats from the Livermore Kubota dealer: [url]http://c34.org/bbs/index.php/topic,3212.0.html[/url] Read the link in Reply #1 in that topic.
I used the correct sized hoses, and that copper elbow that turns under the alternator is, as you say, different sizes at each end. It almost would have been easier for you to use the right sized new hoses, but glad you worked it out. Next time, or when you feel you have to replace the hoses, just do it right: 5/8 and 7/8, the black hose is one inch to the copper elbow 1 inch to 7/8.
IIRC, the old 2 inch HX had one end welded shut from the factory, it wasn't your PO who did that, so don't blame him.
OH? Have you done the alternator bracket upgrade????? [url]http://c34.org/bbs/index.php/topic,5078.0.html[/url]
By the time you're done you'll (almost) have an M25XP just like mine!
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
Stu,
Thanks for the reply. I retract my ????? about the PO regarding welded end of the Heat Exchanger. I could swear I saw his prints on the welded end of the HE? BUT... the 1/2" hoses forced onto the 5/8" fittings and the 1" hose to the 7/8" fitting? Plus the wireless reinforced heater hoses? I get at least a couple of friendly jabs at the PO...
I checked the rub factor on the fresh water hoses. I'm OK there...
I'm just glad I had the chance to correct a possible problem with the upgrade. No more hot engine smell and a better running engine.
Chris
Chris Stewart
S/V "24~7"
1984 Catalina 36 Tall
Hull #251 M25
(SF Bay) Alameda, CA
[QUOTE=chs1517;6703]Stu,
I checked the rub factor on the fresh water hoses. I'm OK there...
I'm just glad I had the chance to correct a possible problem with the upgrade. No more hot engine smell and a better running engine.
[/QUOTE]
Chris, it's not only the black hose, it's the HX against the bracket with the bicycle hose in between.
Isn't it a sweet feeling?:)
We have 2400 hours on our '86 M25. I did the upgrade a few years ago, the bicycle tube just last year.
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
[QUOTE=ProfDruhot;6696]This is the URL that I was alluding to that describes how to disassemble, clean and reinstall the heat exchanger. It is excellent and the photography illustrates all of the pieces of the HX.
[B][I][COLOR="Navy"]http://www.pbase.com/mainecrusing/boat_projects[/COLOR][/I][/B][/QUOTE]
Here's the direct link. While this is a 3" Westerbeke HX they are virtually all the same with only slight differences in length and inlet/outlet positions.
[B][URL="http://www.pbase.com/mainecruising/heat_exchanger"]
Westerbeke / Universal Heat Exchanger (LINK)[/URL][/B]
[IMG]http://www.pbase.com/mainecruising/image/108177589.jpg[/IMG]
[IMG]http://www.pbase.com/mainecruising/image/107682465.jpg[/IMG]
-Maine Sail
https://www.marinehowto.com/
Chris, can you explain more specifically how you purped the bubbles out of the system? I think I get the idea, but just want to make sure I understand. Thanks in advance.
Glenn Druhot
Carpe Diem
New Bern, NC
35* 6' 10" N / 77* 2' 30" W
2001 C36, Hull #1965
Std Rig; Wing Keel; M35B
Glen,
Burping your engine, as far as I am concerned, is hit or miss. Sometimes I am successful on the first try and sometime not so much. Some suggest filling the reservoir with radiator fluid, starting your engine and after getting it warm reving the engine to 3,000 rpm for 30 seconds. Others recommend cracking the hoses at different locations and waiting for the air to escape followed by radiator fluid. Please do a search on the web and you will get all sorts of suggestions. Believe me, I am no expert!
What has worked for me is to make sure my reservoir is full. I then remove the lower 5/8” hose off the lower portion of the thermostat housing (the one that goes to your water heater) and using a small funnel add fluid until it comes out of the hose then quickly replace the hose. I then start the engine, get the engine warm, and continue to monitor the reservoir adding fluid as needed. Now this is the part some will disagree but has worked for me mostly out of chance. The engine temperature will spike at a given point so I carefully monitor the temp. gauge making sure not to overheat the engine. When it spikes I turn off the engine and wait a few minute for the engine to cool. I note if the the reservoir needs more fluid. If it begins to lower a bit you are burping your engine. You should see some bubbles coming up out of your reservoir. Sometimes I remove the heater hose again to make sure there is fluid. I start the engine again and monitor the temperature and reservoir fluid level. I turn off the engine and wait for it to cool. I then secure the radiator cap and make sure the vent on top of the thermostat housing is open. When the fluid starts coming out of the valve close it and look at the temperature gauge.
My last try at burping my engine was frustrating, as it did not go as I had planned. I ran out of time and left the engine to cool overnight. When I returned the next day I topped off the reservoir, as it had lowered while I was gone, put the radiator cap back on, opened the bleeder valve. When the fluid came out I closed it… all was well in the world. Looking back leaving the engine to really cool maybe did the trick?
I ran my engine with the prop in gear to test the system for about ten minutes at different loads. The temp gauge held steady.
I am sure there will be those of you out there that will correct me on my methods. I really welcome your comments as burping the engine is not that much fun. It seems to be the nature of the beast "Universal
M25." This is my fourth time doing it since I bought my boat. If someone has an easier "Sure Fire" (like it works every time and you never get frustrated) method please...share it!
Chris
Chris Stewart
S/V "24~7"
1984 Catalina 36 Tall
Hull #251 M25
(SF Bay) Alameda, CA
Glenn, I've posted this many times here, and will be glad to repeat it: [url]http://c34.org/bbs/index.php/topic,4518.0.html[/url]
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
[QUOTE=ProfDruhot;6708]Chris, can you explain more specifically how you purped the bubbles out of the system? I think I get the idea, but just want to make sure I understand. Thanks in advance.[/QUOTE]
This is the easiest way:
[IMG]http://www.pbase.com/mainecruising/image/112297123.jpg[/IMG]
I designed this a number of years ago and have installed one on every engine since.
Fill the engine as much as you can with antifreeze via the manifold.
Do yourself a favor and lose the crappy, burn your fingers, twist and open "pet cock" and replace it with a real ball valve. This one is male X female to reduce the number of fittings. Then connect a hose barb and a three to four foot piece of clear PVC hose. This hose now becomes your engines new "high spot" for both venting and purging air AND filling with antifreeze.. Open the pet cock and fire up the engine with the hose held high above it and let her run.
As the engine warms and the t-stat opens fluid may rise in the hose. As it drops, when the stat opens, use a transmission fluid funnel connected to the hose to fill it with antifreeze. Eventually the fluid will never dip back into the t-stat cap as the t-stat opens and closes. At that point the system is full and all the air has been purged.
Close the valve.
To drain any remaining antifreeze in the hose simply dip the hose end into an empty soda bottle to capture what is stuck in the hose after you closed the valve and you're good to go. Air and antifreeze DON'T mix well, especially if you are using Death Cool (AKA DexCool)...;)
-Maine Sail
https://www.marinehowto.com/
MaineSail,
Excellent Idea!!! I also noticed spot #8 for your laser thermometer. Out of curiosity, what are the other 7?
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
Maine Sail,
Thanks for the great idea…another project. I have a couple of questions. How did you remove the hand burning pet cock? Can you do this project without removing the thermostat housing? Do you have to drill and re-tap the thermostat housing to fit the new valve? After installing the valve does it all still fit under the engine housing box? Have you had any problems dealing with air in the water heater hose? Does this method take care of that problem also?
Again, thanks for the reply.
Chris
Chris Stewart
S/V "24~7"
1984 Catalina 36 Tall
Hull #251 M25
(SF Bay) Alameda, CA
Here is the Universal Service Bulletin for the 2" vs. 3" HX:
[url]http://www.realitycheck.me/docs/Universal_service_bulletin_195_heat_exch...
Chris
Chris Stewart
S/V "24~7"
1984 Catalina 36 Tall
Hull #251 M25
(SF Bay) Alameda, CA
[QUOTE=TomSoko;6719]MaineSail,
Excellent Idea!!! I also noticed spot #8 for your laser thermometer. Out of curiosity, what are the other 7?[/QUOTE]
Water inlet temp at seacock
Return for engine coolant to the HX
Supply for the engine coolant for the HX
Outlet to transmission cooler from HX
Inlet to transmission cooler from HX
Exhaust Elbow up stream
Exhaust elbow down stream
Exhaust manifold for cyl 1,2,3 & 4
Top of t-stat housing
Bottom of t-stat housing
I have all these number recorded at both cruise RPM under load and after five minutes of idle following an extended run at cruise RPM. If I get an overheat problem I can quickly decipher and isolate, based on notes and new temp readings, where the issue is. Makes future trouble shooting FAR easier...
-Maine Sail
https://www.marinehowto.com/
[QUOTE=chs1517;6721]Maine Sail,
How did you remove the hand burning pet cock? [/quote]
With a wrench, righty tighty lefty loosey.
[QUOTE=chs1517;6721]Can you do this project without removing the thermostat housing?[/quote]
Sure..
[QUOTE=chs1517;6721]
Do you have to drill and re-tap the thermostat housing to fit the new valve?[/quote]
Not if it already had the crappy hand burning pet cock you don't. It is a standard NPT tapping and a new ball valve of the same thread will just thread right in with some teflon tape and good pipe dope.. Some t-stat caps are 1/8" NPT some are 1/4" NPT. If I recall mine was a 1/8" NPT male by female ball valve.
[QUOTE=chs1517;6721]After installing the valve does it all still fit under the engine housing box?[/quote]
That all depends on your boat. On my CS 36 it clears it well. The valve and elbow are about 2 1/4" taller than the t-stat housing but there are longer and shorter 1/8" male/female BV's available depending upon the manufacturer. These are normally used as valves for vents hydronic heating systems.
[QUOTE=chs1517;6721]Have you had any problems dealing with air in the water heater hose? Does this method take care of that problem also?[/quote]
That is the whole point of this installation. The new hose becomes the systems high point and all air eventually is bled out, something which is nearly impossible the way the engines comes from the factory, with no way to fill it from the high point.
-Maine Sail
https://www.marinehowto.com/
Maine Sail,
Thanks for the reply. I will be saving this file and modify my system sometime this winter.
Thanks again,
Chris
Chris Stewart
S/V "24~7"
1984 Catalina 36 Tall
Hull #251 M25
(SF Bay) Alameda, CA
I took the boat out yesterday for sea trials and to play with my spinaker. I ran the engine at different rpms and then pushed to almost full rpm. The temp gauge held solid at 160'. There was abosolutely no hot engine smell!
The only thing I have to do is install a rubber gasket or material between the HX and the engine bracket.
I also took a couple of pictures of the old HX. Note the welded end. It was definitely an after market weld. One can only guess why the PO had it welded shut. I would guess the bolt threads stripped or the shop could not get a good water tight seal??? It's anyone's guess?
Thanks for all of your inputs...
Chris
Chris Stewart
S/V "24~7"
1984 Catalina 36 Tall
Hull #251 M25
(SF Bay) Alameda, CA
[QUOTE=stu jackson c34;6701]
the old 2 inch HX had one end welded shut from the factory, it wasn't your PO who did that, so don't blame him.
[/QUOTE]
I just attempted to change the zinc on my new (to me) c36 with an M25, and when I removed the bolt there was no zinc attached. Then I tried to insert the new zinc and discovered that the hole is plugged (probably the old zinc). Problem is, I have the old 2" HX, so the end cap by the zinc cannot be removed. Any thoughts as to remedies?
Or should I just replace the thing by upgrading to a new 3" HX, and if so, any suggestions for where to get one?
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
'Cause that's where I step when I am climbing down into the cabin and the engine cover and companionway steps aren't in place.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
I had the overheating problem also. I researched the universal updates and saw that they suggested that the upgrade to the 3" heat exchanger would stop the engine from overheating.
I oreded everything from Hasen Marine in Marblehead MA they have a mechnic there that I think could take apart a M25 in his sleep told me exactly what I needed.
SOLVED THE PROBLEM little pricey but better than blowing a head gasket, or engine for that matter
FAIR WINDS & FOLLOWING SEAS
Jeff Costa
S/V KAIROS Hull #0235
[QUOTE=chs1517;6690]
I purchased a new 3" HE from a local shop and returned to my boat with the HE, a set of new hoses and SS clamps in hand.
Replacing the unit was simple enough. I resecured the HE onto the original HE engine bracket with larger and brand new SS clamps. Now the fun began. The PO???? What was he thinking? I discovered the 1/2" hose the PO had used to connect the HE to the water pump should have been a 5/8” hose. The PO had forced the smaller ½” hose onto a larger fitting??? [/QUOTE]
Having just performed this upgrade a few weeks ago, I discovered that the old 2" HX in fact DID have a ½" fitting for the hose from the raw water pump, while the replacement 3" HX has a 5/8" fitting. Thus, seems like the PO had the correct hose size. The solution (for me) was to fabricate a reduced barbed coupling to go from 1/2" to 5/8".
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
[QUOTE=Chachere;8489]Having just performed this upgrade a few weeks ago, I discovered that the old 2" HX in fact DID have a ½" fitting for the hose from the raw water pump, while the replacement 3" HX has a 5/8" fitting. Thus, seems like the PO had the correct hose size. The solution (for me) was to fabricate a reduced barbed coupling to go from 1/2" to 5/8".[/QUOTE]
Here's a photo of the old and new heat exchangers. Besides the greater diameter of the newer HX, you can see that it is also shorter, and the fittings are not all the same size nor oriented exactly the same as before. I don't know if the different fitting sizes and orientations are because its an aftermarket replacement (Seakamp) as opposed to a "genuine" Universal replacement. In any event, it will fit, after some "persuasion" and adaptions.
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Thanks to this post I easily upgraded my M25 from a 2 inch to a 3 inch heat exchanger. Today I could push it hard at full throttle and the engine stayed right at 160 degrees. Before I had to watch the temp or it would go well beyond 180.
Mike and Sarah Dickinson
Mes Trois Filles
Holland, MI
C36 / 1984 / Hull 0219