mlenoch

Didn't see the venting but:

'51 normally vented on TO if run started with too high a coolant
temperature (taxied out with doors closed). Rule was that if you
popped off, you returned and landed (even if venting stopped) as there
was no way to tell how much you vented and with low coolant, engine
could overheat.

If bird continued to vent around the pattern then the coolant was low
and running hot and at a high enough pressure to keep the 'pop off'
valve open or valve not closing after opening (spring loaded valve).
Pressure to unseat valve and open was greater than pressure to keep
open.

Or. If bird 'popped off', then the valve could stick open since there
was not anyway we could check it on a routine basis. Never heard of a
pop off with engine coolant temperature in the operating range. Valve
had a fixed pressure setting that could not be adjusted by crew chief.

It was a low maintenance item on bird.

I saw a few 'pop offs' in my three year in the Sq but never saw or
heard of one that stuck open.

With the age of the birds today however and an original 'pop off'
valve, it well could stick open after popping off. Like a PRV on a
water heater in your house. Don't leak unless it opens to relieve
pressure and then does not fully close due to build up on seat.

Bottom line is glad he made it around and back on ground OK. It is
enough of a potential emergency to warrant landing priority.

Big John
650 hrs in '51


On 05 Aug 2003 04:08:05 GMT, (MLenoch) wrote:

BTW: Whatever happened to the Mustang that was "venting coolant" on Friday?
(Or was it Saturday?)

Saturday. He was indeed venting. His pressure relief valve let go too soon
(at too low a pressure). A simple fix to get a new valve, gasket or do a
repair. He may be home by now.
VL