Viscous/Clutch Fan replacement

[Chuffer]

I can live with that .

 

[Roscobbc]

My understanding is that ideal engine temperature is about 212 deg F so that water in the oil caused by combustion blow by is boiled off.

Also C3 gauges have the pointers in the vertical position generally so that you can just scan the set to see all is well.

Post '75/'76 American cars, (not just Vettes) were designed with low compression ratios and ultra lean a/f ratios and ridiculously retarted idle timing. These lean burn engines were the only way that specific types of emissions (oxides of nitrogen?) could be reduced. 'In the day' the lean mixtures caused all sorts of issues with makers devising bizarre means of combatting them. Running at elevated temperatures was fairly typical, and yes later C3's did (still do/can?) run at 212 degrees. Vetman's comments are valid although perhaps nowadays perhaps running with a 180 or 190 degree themostat and frequent oil changes irrespecive of mileage keep condensate in the engine to a minimun.

 

[Chuffer]

My 1980 C3 runs with a 1985 Camaro IROC - Z28 5 Litre with a 9.5 : 1 compression ratio which is up on a base spec 1980 5.7 Litre so I guess I am gonna be all the place with what to expect is the norm .

 

[Vetman]

Anyway, my 75 has a 180 deg F thermostat fitted and runs at 200 deg F (needle vertical) and got up to about 205 in traffic on the way home from the Nationals. I was relieved that temperature stayed below the red zone. Without AC I was boiling instead.

 

[Forrest Gump]

............Running at elevated temperatures was fairly typical, and yes later C3's did (still do/can?) run at 212 degrees.

Of course C4's which have basically the same sbc engine as the C3, are designed to run that much hotter - Their fan doesn't kick in until 228 degF

I've had an electric fan on my C3 for the last ten years which has always done the job well. The thermocouple controller is set to switch on fan at 200F except the thermocouple packed up a couple of years ago and I haven't got around to fixing it yet. In the mean time I'm using the manual over-ride switch on the dash to switch it on if I see the temp going much over 200F. I really should fix the controller of course, but it's surprising how little I actually need to switch on the fan - I will often do a trip and not use it at all.
On the hot afternoon return from the Nationals, the controller failure went one stage further - The switch relay jammed and I couldn't get the fan to switch on at all....but I still managed the whole 85mile journey without overheating which I thought was good going. I saw 225 a couple of times after I was booting it, but generally kept around 200F on it's own.