Radiator Cap--flow rate through radiator

[Terryk]

Or my 1970 Firebird that would overheat without a thermostat. The coolant
went through the radiator too fast to have much heat removed from it.

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> From: John Hess <JohnH at ixc-comm.net>
> To: 'diy_efi at coulomb.eng.ohio-state.edu'
> Subject: RE: Re[2]: Radiator Cap--flow rate through radiator
> Date: Wednesday, October 15, 1997 8:40 AM
> 
> Don't forget that the amount of heat transfer (both in and out) are
> somewhat dependant on differential temperature.  The greater the
> temperature differential between radiator temperature and ambient, the
> larger the temperature drop within the radiator.  Water moving too fast
> will not sink up as much heat in the heat developing portions of the
> engine AND will not cause as high a temperature differential in the
> radiator (between radiator and ambient), resulting in higher engine
> temperatures, even when the coolant temperature reading is lower.
> 
> I once had an MG that ran at it's coolest (per the temperature gauge)
> when there was no water in the radiator.  Don't get caught up in coolant
> temperature readings as the sole source of information.
> 
> 
> > ----------
> > From: 	michaels at telerobot.com[SMTP:michaels at telerobot.com]
> > Sent: 	Tuesday, October 14, 1997 10:47 AM
> > To: 	diy_efi at coulomb.eng.ohio-state.edu
> > Subject: 	Re[2]: Radiator Cap--flow rate through radiator
> > 
> > <<File: RFC822 message headers.txt>>
> >      
> > 
> > 
> > ______________________________ Reply Separator
> > _________________________________
> > Subject: Re: Radiator Cap
> > Author:  diy_efi at coulomb.eng.ohio-state.edu at Internet
> > Date:    10/13/97 8:24 PM
> > 
> > 
> > There's a problem with the argument below.  If the water is in contact
> > with the 
> > block long enough to pick up some thermal energy (and no matter how
> > small the 
> > time of contact is, there _will_ be a thermal transfer if there is a
> > difference 
> > in temperature), then it will be in contact with the radiator fins
> > long enough 
> > to get rid of the same amount of thermal energy, provided the radiator
> > is 
> > properly designed.  Obviously if the radiator is too small, or
> > clogged, or 
> > bypassed, or what-have-you, then the temperature of the water will
> > continue to 
> > rise as time goes by.  
> > 
> > 
> > 
> > 
> > 
> > Not only does it not absorb enough heat from the engine, it goes
> > through 
> > the rad so fast it doesn't release the heat either. Getting the
> > coolant 
> > up to a high enough temp  gets the temp difference at the rad higher, 
> > allowing the rad to shed more calories or BTUs. This effectively
> > removes 
> > more heat, even if the operating temp is a bit higher. I know it does 
> > not make a lot of sense, but without a restrictor in an engine running
> > 
> > without a stat, overheating of the valve area, for instance, with 
> > resulting head cracks and/or detonation can be a real problem.
> > -- 
> >                              _/\_
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> >      
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> > It's hard to soar like an eagle when your stuck with a bunch of 
> > turkeys-- or stuffed with too much Turkey!! Happy Thanksgiving 
> > to all our Canadian Friends!!!!
> >