Thermostat Replacement - Tempature Rating Significance? (78 450SL)

[jnanasakti]

I'm looking online for a replacement thermostat, and I see that there are a variety varying from 167 degrees to 195 degrees. Can anyone tell me what significance of the temperature rating is? Does it mean the thermostat can handle up to 167 degrees? Thanks

[wbain5280]

It means the thermostat opens at 167 or whatever temp it's rated for. Check with the dealer for the proper temperature.

[Arthur Dalton]

That chassis/yr takes a 75 C [167 F] thermo...

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=2AO123CS42CB0QGFCN&year=1978&make=MB&model=450-SL-002&category=G&part=Thermostat+Kit

[jnanasakti]

Thanks guys. I don't know if this is a dumb question, but why would someone want to place a thermostat that opens at a higher temperature then the standard 167 degree specification? It seems to me that you'd want to cool the engine as soon as possible?

[Skippy]

Engines tend to run more efficiently when warmer-up to a point. Too hot and bad things happen. Too cold and other bad things can happen.

[meltedpanda]

these gals are designed to run hot, but stick to the right thermostat, no reason to mess with design specs...my 2C

[cheapold280ce]

A point missed on thermostats, there are two types ones that fail open and ones that failed closed. Whichever temp you get , you want to get one that fails open so you don't overheat. I would think, that's all that mercedes uses but I am not sure just in general for every car I have I use the fail open type.