playsdixie

not sure my 85 runs cooler with the a/c on, but the aux fan definately makes a difference....when the a/c is on....I have a manual switch...

leesvet

<---- big grill

luckydekko

My LT1 would hit 230 and once or twice 250. Its supercharged though and thats normally when im sitting in 30 miles of traffic. I just took the motor apart because of a blown head gasket but I think in part thats what was causing the heat to begin with. Overall my car ran fine and seemed to have plenty of power until the oil and water was shorting out my knock sensors and the starter lol

1cooldaddyo

My '85 runs somewhere between 195 and 230 depending on a lot of factors.
The previous owner has done something to the primary fan so that it runs constantly. With the A/C on and therefore the auxillary fan, it stays right around 195-200 at all times.

As to durability at high temps... I used to have an '84 Monte Carlo SS. When I bought it, the temp was showing 240+. I immediately replaced the thermostat, water pump, and temperature sender; all with no effect. So I wrote it off to a bad gauge and forgot about it.
A couple of years later I'm at Autozone and they have a special on fan clutches. $10, what the heck.
Put it on and temp went to 180 and stayed there for the rest of the time I owned the car.
During all that time, I never had any driveability issues at all.

SeanHM

This is something I know I will have to address when I get my Vette. I personally don't like to see anything over 230 and that should only be in stop and go traffic on a 100 degree day. I prefer sub 200, but it depends on where the sensor is located in the system. I know these motors will take it, but as mentioned, it's hard on the plastic and wiring under the hood.
I don't know for certain about the Nascar systems, but when I was racing Prototypes in Grand Am we ran a pressurized cooling system. This increases the boiling point of the liquid allowing you to run higher temps. We also used water- wetter . Anti- freeze is not allowed on the track because it is too slick. 230 was pretty typical, 250-60 was pushing it and had us looking for problems. I'm not sure it would have stayed together long enough to see 290, but then we were running Porsche flat sixes and they had to stay together longer than a Nascar motor. Still seems like a stretch.

gerardvg

My old 350 got cooked many times, blown or split hoses can make that temp really ramp up quickly as others have mentioned.

The old engine had plenty of clearance, that enabled it to go 250-260 without damage. The same cannot be said about the temp sensor in the head, they get screwed real quick.
I make sure i always have a spare temp sensor.

I really watch the temp gauge with my new 383 engine, I am sure it would not cope like the old 350. It is fine on the highway with a/c on 190-200f but traffic light to traffic light idling for prolonged periods will see a bit over 240F before turning the a/c off during 100F + days.

That is with the auxillary fan running as well, even when my vette was standard i would see 230-240 with heavy stop start traffic in Summer.
The early C4 cooling systems were just enough for a standard engine.

We all drive with one eye on the coolant temperature display, one eye on the road. In the 16-18 years i have had my 85, i still do not like comming across heavy stop start traffic in summer. I mean i love my a/c and hate turning it off to keep the engine cool and me overheating.