LT1 coolant temp

The previous owner of our '94 Roadmaster claims that he had a lower temp thermostat put in the engine when the water pump was replaced a few years ago.

The dash gauge never reads in the middle, it always seems to settle right around 3/8 (I don't remember exactly which mark, but less than 1/2) which would support his claim.

But when I check the temp through the climate control module it says 180 when warmed up.

That sounds like it has the correct 180 degree thermostat in it. Right?

If it's a 160 I'd like to replace it, but if it's the correct 180 I will leave it alone.

Can anybody else confirm this is where their LT1 with a 180 thermostat runs?

The position of the needle is almost irrelevant. You can check the actual temperature of the coolant by accessing the diagnostics in the HVAC controls.

Right, that's what I did. I am just used to oem gauges thatbsit right in the middle tt normal operating temp. Hence my confusion.

All of mine have read about the same as yours, left of middle.

Cool, good to know! I can check that off. But I should still probably replace the coolant hoses at some point.

Mine's a 93 but her gauge never went above the 1/4 mark. Except for today when the water pump decided to take a crap at highway speeds and the gauge shot up to the half way mark before I could get Ms. Roadie over to the side of the road without power steering, cause the belt jumped off.

Yikes! Hope you get it sorted quickly and it's just a belt. Any signs of bent pulleys?

I have noticed that the temp gauge on the dash actually reads a bit higher in cold weather for some reason. I'm guessing that the thermostat doesn't have to open fully, leading to a slight increase in temperature in the area of the dash temp gauge sender.

yeah the bearing in the water pump took a dirt nap. Got a new pump installed and she's back up and running again.

buickwagon wrote:

I have noticed that the temp gauge on the dash actually reads a bit higher in cold weather for some reason. I'm guessing that the thermostat doesn't have to open fully, leading to a slight increase in temperature in the area of the dash temp gauge sender.

A reason for that can be no AC use. Putting the AC on runs the fans, bringing temps down.

Think a variable resistor could be put inline like the fuel gauge? You could read the temp on the computer and make an adjustment until the gauge reads correct

I have yet been able to dial in the fuel gauge using the variable resistor.  The little blue one from radio shack is too flimsy  ( breaks easily) and too sensitive to minute change. might work better with a potentiometer closer to the actual value needed. You'd get less sensitivity to the angular change of the knob. The it's too easy to sweep right past the setting you need. they make a 1k and 10k version. I'm not sure I've tried in the past. The 1k would seem the better bet

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Get a "10-turn" potentiometer. Great for fine adjustments because they are literally 10 turns from 0 to the uppermost limit.

Got an example (pic) to show what we might be looking for, or a link?


Many thanks for the info.

Here's the first two that popped up when I googled "10 turn potentiometer":

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Thanks , those look considerably more rugged than the ones from Radiosmack

Dave.