Just getting a feel for what I want to look at, and what is "normal" for my "new" Fiero.
I just put two separate 195 degree thermostats on my car, the last being a Stant Superstat that I'm confident is working correctly. The car only has 10k miles on it, and the coolant is in great shape.
With both, during back street driving and some 50 MPH cruising, the temperature consistently reads just a hair above the 1/4 mark. When I accelerate hard, I can see it want to climb just slightly, and then it cools right back down -- I can almost see the thermostat open and close via the gauge. The heater is blowing hot. The ambient temperature has been between 30 and 50 degrees, so no hot days outside for me yet.
At idle, the gauge will get a notch or two past the middle (220) mark before the fan kicks on and cools things down. I'm confident that is working as designed.
Anyone else have a gauge that rests at the 1/4 mark (except at idle), particularly when cool outside? Theoretically, if the gauge "notches" are linear between the bottom 100 mark and the middle 220 mark, then mine is staying at 165ish -- I don't think that's the case given the 195 thermostat. And, of course, the same distance on the back half of the gauge only covers 40 degrees (220 to 260).
In the end, I'm less concerned with the accuracy of the gauge, but want to make sure the car is getting to proper operating temperature.
[This message has been edited by USMUCL (edited 02-07-2017).]
My 86 and 87 GT's both always read at the quarter mark unless I frequent high RPM's, at which point it nears the middle mark. I do tend to beat on my cars, rather than baby them. So these readings are normal for me all year round.
I think that is consistent with mine -- right at or just a hair past the 1/4 mark until I accelerate hard, then I can see it creep up a notch or two. But then it immediately comes back down to 1/4ish when I get to cruise speed and I'm done accelerating. Again, temperature has been cool outside but not frigid.
Same. Quarter mark when cruising seems fine. When cruising a little faster, say 75-80 it creeps up between the quarter and the middle. When stopping in traffic it likes to hit the middle sometimes but goes back down pretty quick.
Temp gauge is reading numbers are worthless and comparing to another car won't help you. (Is why most cars don't have this. gauge labeled cold/hot or no label and just use red for overheat area.) Too many things will cause temp, oil pressure and fuel gauges to be way off. Any iffy grounds, power, and/or wire from sender can have problems.
Scan ECM is much more accurate and if dash gauge is close ECM data them you not going to get better.
If ECM read high/low too then check for coolant problems. See my Cave, Coolant Fill and rest of section.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
I agree there are many things that affect temp readings, including inaccurate gauges. But, if 1/4ish read on the temp gauge during regular operation is "normal," it is not where I am going to spend my energy.
And, as for "normal," I am probably referring more to "common." Slight but distinct difference . . .
I believe what you are seeing is what you would expect when the car was new, that the behaviour you see is common as well as normal My 7800 mile car behaves exactly the same way.
Mine is a lot like the others here. At 1/4 or maybe a little more.
Someone years ago installed a low-temp fan switch, so the fan comes on at some crazy temp like 160 degrees. So even in a four-mile drive to work, the fan comes on at the halfway point. Next time I drive it, I'll use the scan tool to confirm exactly what the temperature is.
Mine is a lot like the others here. At 1/4 or maybe a little more.
Someone years ago installed a low-temp fan switch, so the fan comes on at some crazy temp like 160 degrees. So even in a four-mile drive to work, the fan comes on at the halfway point. Next time I drive it, I'll use the scan tool to confirm exactly what the temperature is.
Halfway is 220, and it is supposed to come on at 235 anyway -- or do you mean your fan comes on at halfway between the 100 and 220?
Neither... Halfway between home and work, which is about two miles.
Ahhh, okay. Bottom line, your gauge sits at about the 1/4 mark during normal operation (except when idling, when it rises to some point at the fan kicks on)?
If I don't have a scanner but want an idea of what the coolant temperature is actually at, and I get an IR Thermometer from Lowes, do I just point it at the thermostat housing just below the cap?
About 1/4 up on my 3800SC. With the champion radiator, measuring with a laser thermometer and using a 180* stat I get consistent 180* coolant temps and trans oil temps
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Yea, thanks all. Just to close this out, I have since found numerous posts of folks who say their Fieros ran at the 1/4 mark until sitting still.
There is much talk about the inaccuracy of the gauges. But, I saw one post on this forum where the Fiero owner claims that each mark above 100 is worth 25 degrees until the 1/4 mark. At the 1/4, you are at 200, and each subsequent mark on the gauge is 5 degrees. When I put an IR thermometer on the thermostat housing, it is VERY CONSISTENT with this logic, plus or minus a few degrees that I presume can be chalked up to a cheap thermometer. Its at 200 at the 1/4 and 220 at the 1/2. Fan kicked on at 235 (which was three marks ahead of 220) and off at 225ish (one mark further than the middle 220).
My 7800 mile car behaves exactly the same way.
Halfway between home and work, which is about two miles.
