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350 chevy running to cold?

11K views 12 replies 7 participants last post by  curtis73  
#1 ·
hi there im new to this forum, looks like a decent forum for v8's, im tiaan 22 from south africa, i have a ford sierra with a 350 chev installed.
Whats the minimum operating temp for this chevys? I got a 74 celsius (think its 165 fahrenheit) thermostat and the fan switch is about 76 celsius,but kicks it at about 80, when im driving in town the temp is about 88 to 100, but when i drive on the open road it goes down to bout 70,is that to low?
 
#7 ·
your numbers are about right.. they suggest that you need a bigger/better electric fan. if it climbs up as you idle.

71°C to 90°C is totally acceptable operating range.
even 100°C is ok.. but I wouldn't want to get any higher then that, just leave some room for error.
if you start getting up to 105°C it's time to worry.

110°C (230F) is where damage CAN start to occur... namely your head gaskets.. and once the coolant starts to boil, it's ability to cool is dramaticly reduced, and the engine overheats even faster creating a cascade effect.

I personally have had a chevy 350 up to 300°F (148°C) and it survived... (long story)
 
#8 ·
Some new cars have 90 (195) degree stats and the fans don't even kick on until 110 (230). I disagree with kc8oye. 230 is the point where many coolants start to boil, but that's not the point where damage starts to occur, and certainly not at the head gasket.


mrt86, it sounds like you have a 160 thermostat, which translates to about 71 degrees, or its possible you have a different thermostat that is stuck open and not allowing it to get up to temperature. Many hotrodders put a 160 stat in their engine because it can sometimes boost power a bit, but 180-195 (82-90) stat is healthier for the engine. The main issue is that the oil gets all kinds of contaminants from the engine, some of which are water and acids. If the temperature of the oil never gets hot enough, those impurities don't evaporate off and your oil life can be shortened.

Your thermostat probably has the temperature right on it as part of the part number or just sometimes its stamped right on the body of the stat. Some common temperature ratings are 160, 165, 180, 195. (which translates to 71.1, 73.9, 82.2, and 90.6)

As long as you're not boiling coolant, hotter is healthier. If the OIL temperature gets above about 230 (110) then the oil starts cooking and getting damaged.
 
#9 ·
operating temps

165 farenheit is not too low to run the engine at. In marine applications sometimes folks run the engines with a 160 thermostat to keep the salt water from ruining the water jacket, on raw water systems, but in a car the temps should be greater than 185 to maybe 215 farenheit. I think that anormal operating temp of 195 is ideal. The temps must be within these numbers to get proper combustion, if you run the car at lower temps the gas mileage will be terrible and the power will suffer. Better heat her up dude!
 
#11 ·
water boils at 212F or 100 C. Physics says that for every psi water has forced on it it raises the boiling point 1 degree F. For every lbs of vacuum it is reduced 1. This is what causes "the bends" in scuba diving the rapid loss of pressure causes Nitrogen in the blood to evaporte and form bubbles. So if you have 1 bar (14 lbs) radiator cap you raise your boiling point to 226 with straight water I don't know how antifreeze affects this. Some of the import cars come with 17lbs or higher. this is why they can sustain such high temps. The new cars run higher pressure that is why manufactures removed the numbers from the temp gauges. People would bring cars in because they thought their motor was over heating when it ran down the highway at over 212.
 
#13 ·
kc8oye said:
and since most of us are not striving for maximum emissions reductions.. cooler is better.. up to a point...
At the risk of reducing reliability, yes. Its all a trade off. According to long term studies by manufacturers, for every 5 degree reduction in temperature, you reduce oil life by 12%, which (by the SAE testing standard) means that if you change your oil at 5000 mile intervals, engine life is reduced by 30% on the average. If you change oil at 3000, its reduced by about 20% on the average.

Since reducing temps by 5 degrees is only good for about 1-2 hp (which can't be felt or measured) I think I'll stick with hotter temps. If it were a race-only car that you change oil every race, maybe, but I get so frustrated with people setting aside major reliability issues just for 3 hp on the street. To each his own, but not for me.