I like to hear about weird problems with cars, and I assume some
others do as well. On that note, I wish to report on a problem I
recently had with a coolant recovery system.
For those not familiar with coolant recovery systems, a brief
description: When the engine gets hot and the spring-loaded radiator
cap relieves some of the pressure built up, the coolant released is
piped into an overflow container. As the engine cools and vapors in
the cooling system condense, a small button in the center of the
radiator cap seat allows the system to suck the coolant back into the
radiator. This saves coolant and reduces pollution. It also keeps
the coolant system totally full and free of air, since each cycle
serves to bleed air out.
One of the problems I have encountered several times in the past is
the pickup tube within the overflow container sucking against the
bottom, and therefore not allowing coolant to be drawn back into the
system. This is a remarkably common problem, and I recommend to all
that it be addressed in advance. One easy fix is to trim the tube
within the container short enough so the end is 1/2" or so above the
bottom -- a fix that will also have the effect of leaving crud in the
bottom of the overflow container rather than allowing it to be sucked
back into the cooling system. It is also a good idea to cut a complex
shape in the end of the hose to minimize the chances of it sealing
against the inside of the container.
The problem I am currently reporting looked just like the typical
tube-sucked-against-the-bottom problem: The overflow container was
totally full (way above the MAX line on the side) and the radiator was
low. In this case, the cooling system was definitely trying to draw
the fluid back, because removing the radiator cap made a giant sucking
sound that would have made Ross Perot proud. It sounded like removing
the gas cap on some modern cars.
The only problem was, I had already worked on the end of the tube in
the overflow container on this car, and looking at it again gave the
distinct impression there was no way it was the problem. The hose
also proved to be clear.
One last check, which proved in fact to be the cause: The little
button in the center of the radiator cap seat was stuck shut! I had
to pry on it fairly forcefully with a fingernail to get it loose. It
was clearly stuck well enough to cause the problem. Once loose, an
inspection indicated there was nothing wrong with the cap. There was
no crud involved; it appeared that the metal button had just been
sitting on the rubber radiator cap seal long enough it had become
adhered to it.
I guess the moral of the story would have to be: whenever you have a
radiator cap off, fiddle with the little button in the center and make
sure it is operating freely.
--
--- Kirbert
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| Kirby Palm, P.E. |
| palmk@freenet.tlh.fl.us |
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|