[C320-list] Intermittent coolant leak

[Warren Updike]

For those challenged by basic engine maintenance, anyone owning a 320 can do the basic stuff to keep your kitty purring along. Here is some things I've learned along the way:

The coolant overflow connected to the top of the heat exchanger should never be empty. When cold it should be at or above the "Cold" mark, and when at "NOT" (normal operating temperature,) it should be at or near the "Hot" mark. If it is too low, just open the cap on the overflow bottle and poor in sufficient coolant to the proper mark. Because the coolant expands and contracts as the engine warms and cools, the excess coolant will move in and out of the heat exchanger. This assures your engine will always have the proper amount of coolant regardless of temperature. 

As for the coolant, it used to be that the color mattered and we were not to mix colors. I'm not real sure; but, I think most coolants today can be mixed. I buy only pre-mixed coolant at auto stores. It’s already mixed 50/50 with distilled water. I'm not sure what color it is as I'm color vision deficient. Just like with batteries, nothing but distilled water should ever be put in your engine. Yes, the pre-mixed is a tad more expensive; but, the engine only holds about 1 gallon. Go for it. Also, if in doubt, ask the store clerk about the color mixing issue. To be sure, start by flushing your cooling system.

Every year I remove about a quart or two of coolant and replace with fresh stuff. If you have never drained and flushed your heat exchanger, perhaps you should consider doing so. Instruction are on the internet. Then, you should only need to replace a part to half of the coolant each year or two.

If I've misstated any part of this, please correct me. I'm only a man.

Warren and Pattie Updike
1994 C320 "Warr de Mar" #62
Middle River, MD (Chesapeake Bay)

-----Original Message-----
From: Dave Hupe [mailto:hoopdtwo at yahoo.com] 
Sent: Monday, July 23, 2018 7:16 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Intermittent coolant leak

 Sara-
I do not have your engine (mine is Perkins M30), but I offer a few comments as "food for thought".
1.  Normally you should have some coolant in your overflow tank.....it should not be dry!  There should be a "low" mark on the overflow tank.  You should add properly mixed coolant to the overflow tank to this "low" level mark when the engine is cool. 2. What is the level of coolant (with engine cool) in your heat exchanger tank (you said you replaced the radiator cap, so I hope  you confirmed it is full enough)?  Are you overheating slightly and the engine expelling minor coolant (which should go to the overflow tank)?3.  Check the small diameter fluid tubing that runs to the overflow tank from just under the lip where the radiator cap sits.  Maybe the hose is loose (clamp loose), or the hose is cracked and fluid is seeping there rather than getting to your overflow tank. Replacing this hose would be inexpensive and easy.
Dave Hupe
1994 Cat 320 "Mayan Sun" (#32)
Holland, MI