FAQ: Overheating - Heat Exchanger?
Overheating with 2" heat exchanger, can I install a 3 inch instead?
I am overheating with 2" heat exchanger
How much is the 3 inch heat exchanger and how difficult is it to
change? Where can you get it?
I think I paid something like $180. Canít remember exactly. Very easy
to change. You have to fool with the mounting brackets but that is it. The
hose connections are the same.
Mike: I bought mine from Torrenson Marine. Found them on the web:
http://www.torresen.com/~torresen/universal/welcome.html. I called on the
phone, they were fast, helpful and expensive. About $400.00 for the
exchanger. It fit right on the same mounts as the old one. It has been
flawless. The engine temp has routinely been 160 instead of 185-200.
I finally broke down and bought a 3" heat exchanger. You have a
lot more margin in the system plus you can take off both ends of the heat
exchanger for cleaning out the zinc pieces.
Hi Stu, I get all my stuff from, can't remember the name but their
number is 707.426.6670. They are great. The heat exchanger is expensive
though, about $350.00 but the installation is straight forward. You will
need a piece of 3" steel pipe to reshape the bracket and that's tough
to find. I have a piece if you can arrange a pick up. I took the bracket
off the engine to reshape it. Simple job. You mares well change the hoses
while you're at it.
I fought overheating on my 1986 Catalina with 2" heat exchanger
for a long Time, like 5 years. I live in NW florida in warm water. I agree
that the 2" is marginal (so does Catalina since they switched to the
3".) However, if everything is tip top the 2" will keep up. If
you are going above thermostat temp under any conditions, full throttle
for example, you have at least a minor problem Start with the sea water
system: Check for grass/barnacles in intake and filter, new impellor in
sea water pump (old can look good but be stiff and not sealing well),
broken impeller blade from an old impeller problem somewhere down stream.
Take out heat exchanger and shake it. If it rattles you have old tips of
pencil zincs inside. (The dissolve in the middle and the tips stay in
there.) They will plug the cores and are a major cause of overheating
problems. Take exchanger to radiator shop and have it boiled out. That may
not do it. If you pound and shake long enough you can get them out of the
pencil zinc insertion hole. Check for bent or pinched hoses impeding water
flow. Check for carbon buildup where the sea water dumps back into the
exhaust pipe partially blocking the water flow. On the fresh water side,
if you have air in the system, you will get inefficient flow and pump
cavitation. Look at the check valve between the overflow tank and the
plumbing to the hot water heater. (located in cockpit lazerette) This
valve is not made for antifreeze. I recommend replumbing the rubegold burg
plumbing valve at the rear of the engine used to control amount of heating
going to the hot water heater. It is a major source of cavitation and air.
Replumb the hot water heater to the thermostat bypass fittings (short hose
between the fresh water pump and the thermostat housing) [That's the way
the new engines are plumbed] Try a new thermostat. It may be stuck closed.
(take it out and see what happens) Your problem may be one or several of
these items each contributing a minor amount of inefficiency PS. I finally
broke down and bought a 3" heat exchanger. You have a lot more margin
in the system plus you can take off both ends of the heat exchanger for
cleaning out the zinc pieces.
Subj: Re: M25XP Heat Exchanger
Donít mean to get "preachy" (My wife accuses me of that)
but just like in sailing where we use specialized terms like
"halyard" or "sheet" instead of "rope", the
proper terms lead to better communication. The "exchanger" is a
rolling pin sized copper tube mounted just above the transmission at the
stern of the engine. It wont rust. The item that the radiator cap and fill
neck are attached to is probably called something like the "exhaust
manifold water jacket". ( I haven't ever seen it individually named)
It is part of the "maximizing" that Universal/Westerbeke do to
the Kubota tractor engine. I believe that it is made out of cast iron
which will rust. Anti freeze is very corrosive and will cause rusting. I
believe that you do not have a major problem. Clean the spot up and spray
paint it would be my advice.
Important: The opinions expressed here are those of the individual contributors to this page, and not those of the Catalina 34 National Association or Catalina Yachts, Inc. Additionally, this material has not been reviewed by Catalina Yachts, Inc. for technical accuracy. This page's maintainer cannot guarantee the accuracy of this information or the desirability of suggested modifications or upgrades. Please obtain assistance from a competent marine mechanic or boatyard prior to making any significant modifications to your vessel.
Last modified by Phil Imhof, Wednesday, August 11, 2004 . Copyright © 2001 by Catalina 34 International Association. All rights reserved.