[Healeys] Thermostats

[Robert Duquette]

I beg to differ.  ;)  We have 2 seasons in Ottawa (ON Canada).  Winter and 'road construction'.

( Others agree that we have 2 seasons, but name them differently. "Too Hot" and "Too Cold". )



This summer was particularly hot, with high humidity.

Month starting on    Maximum    
Sep 2018                  32.0 °C     
Aug 2018                  32.8 °C     
Jul 2018                    36.0 °C       
Jun 2018                   33.6 °C       
May 2018                  29.8 °C


This seems to think that we have 4 seasons???

https://en.wikipedia.org/wiki/Ottawa#Climate


Robert
55 BN1




On Sep 16, 2018, at 02:44 PM, Harold Manifold <manifold at telus.net> wrote:


I tried to help myself but I have once again been drawn into a discussion about engine thermostats. As I read the posts the underlying questions are what is the best thermostat and do I have the right one? I will correct one Poster who suggested the role of the thermostat was to control pressure in the cooling system. While thermostats may have an effect on pressure in the cooling system that is the job of the radiator cap.
 
I suggest the best thermostat has these features: fails in the open position i.e. coolant circulates through the radiator. You can get home with a cool engine but not a hot one. Blocks circulation of coolant between the engine and radiator until the engine has reached its predetermined temperature. i.e. The thermostat fits the housing and seals when closed. The thermostat fully opens about 15-20 degrees above its rated temperature. The thermostat should have a “jiggle pin” or “check valve” that allows trapped air in the cooling system to pass through the thermostat and be released from the system.
 
Do I have the right one? Based on old manuals I have seen there were two temperature ratings for 3000 Healeys, Summer 70 Deg C/160 Deg F and Winter 86 Deg C/185 Deg F. I believe the thinking behind the two thermostat approach was to reduce boiling the radiator in summer and to make the heater work better in the winter. Depending on where you live and and the driving conditions may influence which end of the range you want to be at. If you live in Florida and/or drive in slow moving traffic I would suggest the 160 degree. Your cooling system will have more reserve when traffic slows. If you live in Ottawa 185 is likely better as it is winter all the time. However, the most important factor is not opening temperature but does the thermostat properly control the coolant temperature. If you have a 160 degree thermostat and the coolant temperature fluctuates between 160-180 then it is the right one. Likewise the 185 should stay between 185-205. It is most important for the cooling system to stay between the lower and upper temperatures. If the temperature is not between these two points then the cooling system is "not in control".
 
Bottom line is if the cooling system is "in control" and you are happy with the way the car warms up you have the right thermostat.
 
Harold
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/healeys/attachments/20180919/8f8ae9c0/attachment.html>