Temp Guage

In searching other posts concerning temperature guages i could not find where exactly 180 degrees is supposed to be on a 1998 with a 5.7. The engine will warm to about two lines before the 210 degree mark then drop down to below the larger line between 100 and 210. After that it will gradually work its way up to one line above the halfway point. I am assuming that the halfway point is about 160 given a perfect world and the guage is acurate. I only bring this up because on a recent trip to the smog shop I barely passed and was told that my engine was not warm enough. This was after a 45 minute drive from work. Being as the guage reacts as is does while warming up, my guess is that thermostat is working but is the wrong temperature and needs to be replaced.

In searching other posts concerning temperature guages i could not find where exactly 180 degrees is supposed to be on a 1998 with a 5.7. The engine will warm to about two lines before the 210 degree mark then drop down to below the larger line between 100 and 210. After that it will gradually work its way up to one line above the halfway point. I am assuming that the halfway point is about 160 given a perfect world and the guage is acurate. I only bring this up because on a recent trip to the smog shop I barely passed and was told that my engine was not warm enough. This was after a 45 minute drive from work. Being as the guage reacts as is does while warming up, my guess is that thermostat is working but is the wrong temperature and needs to be replaced.
Thermostat is a Good place to start.
One of them no touch laser tempture guns works slick on telling what the tempt is.
Point it and pull the trigger and you got it.
A good OEM thermostat should hold it around 195 degrees.
MT

Thanks for the reply. Don't mean to sound too stupid but where is 195 on the guage? One mark before 210? Thanks.

I would guess so, that's about where my 96 runs.

Thanks for the reply. Don't mean to sound too stupid but where is 195 on the guage? One mark before 210? Thanks.
well on the factory guage you have to take an educated guess. If the known marks are at 150 and 210 and then 240 or whatever you just have to guess that somewhere around the 1/2 way mark between 150 and 210 is 180 so 195 would be a little to the righ of that.
Other than that your best bet would be to get an aftermarket autometer analog or digital ( I think they make digital too) where the graduations in temp are better defined. Thats always been an issue with the OEM temp guage on just about all the GM products. Another way is to get a scan tool and let truck warm up to normal temp, see what the scan tool reads for the temp, then look at the guage to see what it says. Of course its a little hard to look at the guages quickly while driving and figure out the temp.

Get a aftermarket guage and install it where you can read the gauge easy. One problem is where to connect the temp sensor. YOu might have some luck with removing the pipe plug out of the RH cylinder head??

It would be nice if there were some guages like autometer that could read the temps off the factory temp sendor in conjunction with the OEM gauge. I'm not aware that this can be done?? Maybe someone else knows a better way? YOu get into a situation where its one or the other because you are limited in the access "ports" to use for a temp sendor.

On my truck I'm just concerned when and if it goes past 210. As long as its below 210 and in the normal area it operates in 180 to about 195 then I'm not too concerned. Since I have 210 defined on my factory gauge I can eaisly spot that when it might climb past that mark. Generally factory guages suck. Problem on some trucks is where to mount the guages in an easy to read spot. I know there are some pillar mounts that work fairly well but I'm not that big of a fan of.....but you don't have much choice.

I think most all the trucks use a 195 thermostat.... maybe someone put in a 180 at some point. I think that will affect the emissions on the newer model vehicles?

Thanks everyone. New thermy goin' in.