86 temperature question

[Harmon]

86 350 c10 thermostat replaced with 195

Truck began running hot, so I replaced fan clutch.

Truck now runs at 210 in Texas on hot days with AC blowing.  Should I be concerned as it will go a little over 210 at times too.

[VileZambonie]

How's the radiator?

[Harmon]

I’ve had truck for 7-9 years and never had it replaced or worked on.  No idea about the radiator history.  I just got water temp sensor working and now very aware of its temp while running but not sure what’s “normal”

[hatzie]

I wouldn't worry overmuch about 210°F operating temp in the Texas summer sun.
A coolant mixture of 50% distilled water and 50% ethylene glycol has a boiling point of 223°F.
A system with 15 psi radiator cap will add @ 45°F for a final boiling point of 268°F.  IIRC from High School Physics this is a real world application of Boyles Gas Laws.
The 80's F-Bodies ran around 220°F in the summer and as long as the cooling system was kept up they didn't overheat.  You have a much larger margin even if the pressure cap is not holding the full 15 or 16 psi.

[Harmon]

Good information, I’ll just keep my eye on it and maybe one day get a new radiator if needed. 

[JohnnyPopper]

It's cheaper to get a new cap and remove all doubt.

I ditched my fan and clutch, picked up a lot of extra horsepower.

Installed an electric fan, all good, but noticed fluctuation in temp under loads/hills.

Replaced my cap, runs cooler and has steady temp all day long.....

[Rich84]

On both my Squarebodys when the needle on the Temp gauge is near 210 it is actually at 195. This is based on a scanner reading of Ls coolant temp. sender.

[JohnnyPopper]

That's interesting Rich, a real accurate reading vs an analog hopeful...

I use a laser temp gauge to check for slop on analog sensors.

When they get this old, there's bound to be some slop. 

[FlatBlack77]

My truck has the temperature probe in the driver side head. Its aways right around 10 degrees hotter than the actual coolant coming out. That's comparing the temp gauge reading to the laser thermometer reading of the upper radiator hose and thermostat housing.

Alot of people like to run the probe in the thermostat housing which is fine. Both my trucks had the probe in the head for the dummy light so that's where I put the probe for a gauge

I agree on a new radiator cap. The 79 k10 I had was losing coolant for some reason and I couldnt pinpoint it till I looked at the overflow and noticed it was full. The cap had failed and would let coolant out pretty quickly into the overflow. New cap and never had another problem with it