Temperature always below 130*

[blackfire93]

Ever since I put a 160* thermostat with madz28's tuning for the thermostat in my car, it won't reach a temperature of higher than 130* on the temperature guage. Is it bad for my car to be running this cold all the time? Why doesn't it at least get to 160*. I think the fans are suppose to turn on at 180* but it never gets that high.

[Mark B]

The factory gauge may not be accurate. And with as cold as its been lately, im not surprised that the fan never kicks on. Its possible that the engine is staying between 160 & 180 all the time but the guage is just reading wrong.

However...

If the car is really never getting above 130... The T-Stat is not working correctly.

[blackfire93]

Even on a hot summer day it will stay at this low of a temperature. Also, if the thermostat was open all the time it would still get up to a temperature for the fans to kick on sooner or later. Wouldn't it? Oh... and before I put the thermostat in the guage would get up to about 210* - 220* so I don't think the guage would be broken.

[Injuneer]

The purpose of the t'stat is to block off most of the coolant circulation until the coolant temperature reaches the t'stat setting..... 160degF, in your case. Even when the coolant reaches 160degF, it only allows partial circulation, and does not allow full circulation until the system reaches 180degF, or more. If you are convinced the dash gauge is correct, your t'stat is not blocking coolant flow at all, and not allowing the engine to reach the correct operating temperature.

First, verify the coolant temp gauge. The sensor for the gauge is in the drivers side head. If the head isn't reaching more than 130degF you have a condition that can damage the engine. Get a scanner on the ECM. There is a second temp sensor in the water pump housing. That one supplies the coolant temp to the ECM so it can control the fans. Put a scanner on the ECM. The scanner will tell you if the gauge temp is the same value as the ECM sensor.

The 1993 dash gauge calibration is "odd". The lowest hashmark on your gauge reads "100". That is completely different than all the other years, where the first hash mark reads "160". I think the markings on the 1993 gauge is misleading, causing people to assume there is a linear correlation between the first hash mark and the center hash mark ("210") I've seen a lot of people claim that their 93 runs super cool, because of the misleading gauge marking. Compare the dash gauge to the ECM reading.

If the engine is really operating at 130degF, you have the following issues:

-the ECM is not likely to go into "closed loop". That means the O2 sensor feedback is ignored, and the ECM can not correct for changes in the A/F ratio. You could be running rich or lean, and the ECM can't correct.

-at low coolant temps, the ECM increases idle speed, and richens the A/F ratio. That wastes fuel.

-combustion efficiency is reduced, reducing fuel mileage.

-lower combustion chamber temperatures can reduce engine power.

-oil will not reach a temperature high enough to drive off the condensibles that form acids.

[blackfire93]

Ok, I think it's in the thermostat. I took it out and put it in a pot of water on the stove and measured the temperature with a thermometer. The 160 stat opened up at about 140* to 145*. I also tested my old 180* stat and it opened up around 195* to 200*. I guess I'll go and buy a new 160 stat from hypertech. The one I have now was about 1/3 the price of the hypertech but I guess you get what you pay for. I also put the old 180 stat in temperarily to see if the temperature on the gauge will go beyond 180*. It won't be in there long.

[96Camaro]

I have a hypertech, and my temp always stays inbetween 160 and the first mark on the gauge (w/e that is). No matter what weather.

[blackfire93]

Ok, so I've come to the conclusion that it isn't the thermostat. I put the 180* in and took it for a drive. The gauge said that it was only at like 150* but the radiator tube coming from the outlet assembly that goes over top the t-stat was unbearably hot when I grabbed it. This has to mean that the thermostat was opening up right? And it would only open around 190* in my little cooking pot. I also went to take the outlet assembly off about half an hour after parking the car and my thermometer said that it was about 160*. So now I guess the question is if it's the sensors or the gauge. Right? Does anybody know where I can get the part number for the temperature gauge. I tried shbox but I couldn't find anything but the part number for the sensors. Also, will the fans still come on at the correct time even if the gauge doesn't work?

[Injuneer]

The fans are driven by the ECM, based on the temp it is seeing from the sensor in the water pupm housing. The ECM and the fans have NOTHING to do with the gauge or the sensor for the gauge in the drivers side head, between plugs #1 and #3.

You need to get a scanner on there and read what temperature the ECM is seeing.

Are the thermostats you are using the correct ones for the LT1? Did you look at the differences between a conventional t'stat and the LT1 t'stat on Shoebox's page?

Is it possible you have an excessive amount of air in the system, and there is air in the head, which is going to lead to much larger problems. How did you bleed the system after swapping t'stats?

[blackfire93]

I suppose it's possible that I could have an air bubble somewhere. After I put the thermostat in. I run the car until it warms up and opened up the bleeder valves until nothing but coolant just came out. Is there something else that I would need to do?