NC hybrid setup/coolant blows heater core/how to avoid?

[Ross Corrigan]

Howard, I don't know any data specific terms to the heater core failures my
southern friends experienced (I'm in BC and they're all in the US) but it
always went during a WOT dust off of some other hipo car.  They replaced
initially w/ junkyard units, they failed, then with several Nissan units to
find they failed under same circumstances.  My inexperienced slant at it is
they had  a far higher volume/flow than that heater core would normally
experience d/2 their rate of acceleration/ hybrid chevy systems/ and most
likely the Nissan pumps weren't designed for this flow.  If not designed
for that flow and given much higher flow than OEM it could create higher
pressure than they were designed for given their has to be restrictions in
the heater core system leading to this pressure increase (if flow isn't
accomodated pressure goes up).  I agree w/ you that static pressure as you
described shouldn't be a problem as the systems are very similar in design
pressures and all related components were in as new condition.

These were all low 4 second 0-60 cars setup as sweet daily drivers on NA
chevy's.

Not fun having a heater core blow during a WOT high speed run that fogs
your windshield.  Just dont' want that to be me.

thanks again for all this feedback, I"m going to gather them up as a FAQ to
post on my page eventually for us ZV8's.

FWIW, their Datsun heater cores were 20+ yrs old and functioning fine when
they first went, no quality problems their.


At 08:22 AM 5/4/99 -0700, you wrote:
>It would seem to me that no matter what you do as far as restriction,
>as soon as the key is shut off, the increase in cooling system
>pressure will be equal throughout the system.  I find it hard to
>imagine that the heater core would be subjected to enough increased
>pressure from the water pump to be an issue.  The water pump mainly
>creates a pressure differential throughout the system so that coolant
>can circulate..... I suspect that there is very little if any increase
>relative to atmospheric pressure over what the static system pressure
>is.  A good heater core should be capable of withstanding any internal
>cooling system pressure likely to be seen in an automobile with a
>properly functioning pressure cap.         H.W.
>
>
>


Ross Corrigan  /  Vancouver, Canada 

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