

| Subject: | Re: How hot is HOT? |
| From: | Dennis Haynes |
| Date: | Tue, 4 Aug 1998 14:25:42 -0400 |
The fan was probably cycling in high speed to cool the AC,(pressure switch). This is normal. Dennis -----Original Message----- From: Ari Ollikainen <Ari@OLTECO.COM> To: Vanagon@VANAGON.COM <Vanagon@VANAGON.COM> Date: Monday, August 03, 1998 9:59 PM Subject: How hot is HOT? > It hit 100+ in my neighborhood today AND my HIGH-speed radiator fan > cycled on while running the AC and idling my 90/91 camper, waiting in > line to pick up my daughter from summer day camp. The temp gauge > needle NEVER got more than a needle width toward HOT beyond the LED. > This prompted me to think about what constitutes OVERheating versus > just normal operation in HOT ambient conditions. I found some > interesting numbers in Bentley: > > Thermostat begins opening at 85C/185F; fully open at ~ 105C/221F > > Thermoswitch for radiator fan Stage I Stage II Stage III > > Cut-in temp 89C-94C 95C-100C ?? > 192F-201F 203F-212F > > Cut-out temp 81C 87C ?? > 178F 189F > > So...as long as the waterpump circulates coolant AND the faster > radiator fan cycles on and off, the cooling system is health and > doing its job? > > If the cut-out temp for the thermoswitch for stage I is below > thermostat opening temp, this means that the thermostat closes > to keep the engine within normal OPERATING temperature? (DOH!) > Similarly, for stage II, the RRRRRRRR speed has to cool the > circulating coolant down to 189F before cutting off the fan, which > means, again that the thermostat would now be partially closed to > keep the engine within the normal temperature range...which would > tend to explain why there are no wild fluctuations of the needle > in my temp gauge when this is happening since the tempgauge sender > is on the engine side of the thermostat and thus in the "internal" > coolant circulation loop...Typically the needle reaches a needle width > beyond the LED when the either fan speed cuts in. It's still > thereabouts when either fan speed cuts out. Is this normal? > > > > > > > > OLTECO Ari Ollikainen > P.O. BOX 3688 Networking Technology and Architecture > Stanford, CA Ari@OLTECO.com > 94309-3688 415.517.3519
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