M-25XP Cooling Hoses Question

Ward H

.
Nov 7, 2011
3,649
Catalina 30 Mk II Barnegat, NJ
Now on to my next project, the M-25XP on my C30.

I pulled the HX, pulled the end caps off and it looks really clean inside but still going to radiator shop for cleaning.
Pulled the Sherwood RW off as it showed signs of oil leaking. New Oberdopher pump being delivered by end of week.
The exhaust riser manifold flange nuts came off OK but the flange is stuck on the manifold. I've been giving it some doses of PB Blaster and will try some gentle heat this weekend. 8" Hump Hose is ordered.

All the associated cooling hoses need to be replaced. The RW and hot water hoses appear to be 5/8" and the only markings I can find on some of them is "Heater Hose".
The fresh water side hoses appear to be 7/8" and all markings are painted over or otherwise gone. There is a slight bit of blue stripe showing if that is a clue.
There are no fancy bends in these larger hoses but there are a couple of short 90 degree bends.
There are two smaller ID hoses coming off the thermostat housing which have adapters to what appears to be 5/8" hose. One looks braided.

I know hose can be wire reinforced or not but I am not sure what would require wire reinforcement, is it just a cost thing or is there a use where wire reinforced should not be used.

Can anyone point me in the right direction or give me a brief tutorial on what type of hose to put where and what I need to buy pre bent or can bend myself?

Photo of the top of the M-25XP showing smaller thermostat hoses and one of larger bent hose. The second photo shows the short 90 deg bent hose I'm more concerned about bending my self. It comes off the bottom of the fresh water pump of the diesel.
IMG_1601.jpg IMG_1663.jpg

Thanks
 
Oct 9, 2008
1,739
Bristol 29.9 Dana Point
I replaced all hoses with Trident Flex.
Not wire reinforced, but way above heater hose.
More $ but not really that much for all hoses. Easy task.
No prebent required.
Mine's an M18.
image.jpeg
 
Last edited:
Feb 26, 2004
22,770
Catalina 34 224 Maple Bay, BC, Canada
Ward,

Nice work.

The trickiest hose is the one underneath the coolant pump: http://c34.org/bbs/index.php/topic,7084.msg47677.html#msg47677

Others I used Trident, wire reinforced. All over. The 90 deg you show is easy to make do with regular hose.

Surprised that the flange didn't come off, 'cuz there's supposed to be a green gasket between the flange and the manifold.

pm me and I'll send you a tech note I wrote for Mainsheet about putting it all back together.
 
Oct 26, 2008
6,076
Catalina 320 Barnegat, NJ
On the suction side, I started with unreinforced hose from an auto parts store from the strainer to the water pump. It was fine until the 1st time the strainer got clogged. After it collapsed once, it stayed collapsed all the time even as it was drawing just clear water. The reinforcing will prevent collapse and give you smoother bends, without kinks.
 

Ward H

.
Nov 7, 2011
3,649
Catalina 30 Mk II Barnegat, NJ
@Stu Jackson
Stu's link took me to a thread on the C34 site with both a Gates part number and a Dayco part number. Both are listed on line at various auto stores so next time I'm out I'll pick one up.
I'll be back down to the boat on Saturday to measure the lengths I need and will probably go with the Trident Flex hose.
Thanks
 

Bob S

.
Sep 27, 2007
1,771
Beneteau 393 New Bedford, MA
There are a pair of hoses running from the hot water tank to the engine that you don’t see unless you remove the draw unit under the frig. There is a bend in it that was not looking so good when I was behind there. Out of site but if it fails you’ll leak coolant. Worth investigating
 

Ward H

.
Nov 7, 2011
3,649
Catalina 30 Mk II Barnegat, NJ
Bob, thanks for that tip. I will look in that area.
Ward
 

Ward H

.
Nov 7, 2011
3,649
Catalina 30 Mk II Barnegat, NJ
I've done just about everything wrong at least once!:doh:
Hey Scott, that's what friends are for! I need to send you my list of projects so you can send me a Don't do this list.
:biggrin::biggrin:

Picked up a Dayco A 70637 for $3.95 at AutoZone. Looks like it will do the trick for the bottom water pump hose.