heat exchanger..

[RonE]

At what point do you replace the heat exchanger. From my prospective I have never noticed the engine performance or the temperature being a problem. But I did notice especially in the last couple of days, as I did some routine maintenance on the boat , in particular replacing the pencil zinc, is that the H Ex is very corroded and leaking. I usually have a couple of inches in the bilge and i believe now this is where it's coming from. I have the 3" unit. I see they go for 450$ on C dir,  it dosnt look to complicated to replace. ??

[Stu Jackson]

If you need to replace it, do NOT spend $450

http://c34.org/bbs/index.php/topic,6920.0.html

[Ken Juul]

unless it has a hole in it, the end plates gaskets are probably shot.  Take it out, clean it and replace the end gaskets and o rings before you purchase a new one.  Gaskets are available from Sendure or if you have some rubber sheeting are easy enough to make.  O rings are available at most hardware stores.

[KWKloeber]

Ron,

The key is to remove and determine where it's leaking -- most likely the gasket.  If you have a leak in the body it might be repaired, but the key there is the age and condition of the guts.  If the case has a leak, then the core may well be ready to leak between the sea water and closed coolant sides, and that's a throwaway item.  If you have a lak between those sides you will loose coolant as the engine heats and pressure builds in the coolant -- coolant is then forced out to the sea water side of the Hx, and out the exhaust with the cooling sea water injection to the muffler.  Think of it as having a cracked engine block on an auto - you typically will get coolant vaporizing out of the exhaust pipe.  You can test it yourself for leaks, though a radiator shop can "boil it out" and also pressure test it.  If you have to replace, check around and consider getting the better Copper-Nickle Hx over the standard - it's worth the difference especially in salt.  Email or PM me for discounts to Catalina Members, and DON'T pay Universal/Westerbeke list price, and especially on line Un/Wb dealer websites that charge list PLUS 10 to 15%.

Also you mention "corroded" -- they won't maintain themselves - an occasional wire brushing and coat of high temp engine enamel (eg, Rustoleum hi heat) works wonders at keeping them "new." Also be sure that there is rubber beteen the case and mount for protection and that clamps are tight enough to prevent movement, but not tight enough to snap.  AWBA clamps and T-bolts work well for that.

-Ken K

[Ron Hill]

Ron : Take the HX off and take it to a radiator shop.  They can clean it out, pressure test it as well as solder up any leaks.  

If it's all OK, call Glen Mar Marine [800-282-0123 ] and order a Sem-Dur end cap kit for a 3" HX.  A lot cheaper than a new one!

A thought

[RonE]

photo of heat exchanger