Engine Temperature

[sam03v]

Hello,

I've got D-150, 1980 with an '82 slant six engine. I live in Florida. I recently swapped the 1 bbl carb and manifold for a 2 bbl setup. Been driving it for the past couple weeks. When it's about 60-70 deg. F outside and the engine is warmed up the temp gauge will read slightly below the half way point. This morning it was about 30 deg. outside and the gauge was reading dead on midway, or very slightly past midway during my 30 min. drive. I thought this was odd so was wondering if anyone could explain it.

Thanks in advance.

[Megunticook]

When it's about 60-70 deg. F outside and the engine is warmed up the temp gauge will read slightly below the half way point. This morning it was about 30 deg. outside and the gauge was reading dead on midway, or very slightly past midway during my 30 min. drive.
That doesn't sound like anything to worry about. Those factory gauges are not precise, and as long as it's in the ballpark you're fine. How old is your thermostat? Do you flush your cooling system and change the coolant every 2 years? Hold old is the radiator? I suppose one possibility is that you have some gunk floating around your cooling system that may sporadically impede the flow through the radiator.

The ambient air temperature shouldn't have any effect on the motor's running temperature--only the time it takes for the motor to reach that temperature. In other words, it takes longer for coolant that's 30 degrees to reach 190 (or whatever temperature your thermostat opens at) than it does to for coolant that's 70 degrees. That being said, it's certainly true that on a hot summer day in Florida, when you're idling in traffic, depending on what sort of cooling system setup you have and how well it's maintained, you could easily run well above the t-stat temperature...above 200 is not unheard of.

It's not hard to install a mechanical gauge that gives you an accurate reading of the coolant...just did that myself this fall.

[DiverDwnPowrRam]

That is common in florida when it freezes because some do not keep sufficient anti freeze in the radiator and then when it does freeze outside, most do not allow time for engine warm up. If this is true you are lucky you did not break a radiator.