Well, my engine has been running cooler ever since I flushed out the Dexcool. (And no, I'm not trying to revamp the ol' Dexcool argument. Just stating a fact.) I don't know the exact temp, but it's definitely under 200, and it's not tripping anything with the computer either. But then, I have Hyperteched my computer, so maybe that has something to do with it. Who knows...

 

My engine is new along with radiator and water pump 195 deg.Thermostat etc.. runs at 200 to 205..scan tool reads 198 so im close

 

LOL... ya'know... I'm not even sure... I just know this from messing with fuel injected vehicles over the years I guess.
It gets hot down here in Texas and in the summer I used to run 180 thermostats on throttle body Chevy's as a way to trick the computer into enriching the fuel mixture and letting the engine run cooler. This came at the price of not running a cat due to it clogging up and also having to pull out the "check engine bulb" so as not to have an orange glow on my dash at night. (not that I have ever done any of this of course)

But trust me, this doesn't work on the newer OBD2 stuff, also it's not emissions legal.

Oh yea... I don't run Dex-cool either. (and no, we don't wanna get that started up again)

 

I will back Bandido on this 100%. Like was stated before under 200 degrees or so will cause the engine to run in open loop and this will not set alight because the computer just thinks the engine is cold and thats what it is programed to do when the engine is cold.

 

I have 2 vehicles with 4.3's 1 year apart: My 95 runs about 160-170. My 96 runs about 195-200 no matter the outside temp. I asked my dad about it before (gm mechanic retired Sept 2008) - thats normal for both models. He replaced both of my radiators in 2007 and said they were right on the money - therefore I conclude that OBD1 runs cooler and OBDII needs the hotter temps - but I'll ask him to confirm it.

 

I think i have 190 degree thermostat and I run just under that temp. all year in southern missippi heat with the A/C on. I get about 18 -21 mpg consistantly. No issues with O2 sensor or staying in open loop. My vehical is 2wd, with michalin X-Radials (215/70), stock exhaust, with K&N air filter. The water pump is edlebrock and with the edlebrock pump I am running about 10 degrees cooler than when I had a stock water pump installed. My daily commute is all interstate with light traffic. I can set the cruise on 70 for 80% of my drive.

 

My truck runs 195-200 degrees and with the AC on it'll reach 210+ depending on traffic. Has anybody else notice their temps go up when having the ac on during stop & go traffic?

 

X2 and Yup!

 

The temperature rising when slowing down or stopped is not all that uncommon. Most vehicles do this, but not all of them really show it on the gauge. If it rises up a lot, it could be due to a dirty condenser or radiator exterior. A good cleaning once a year should help to keep it clean and properly flowing air to cool your vehicle.

As far as codes being thrown by the newer OBD2 vehicles (98+), I cannot find the source, but I recall the value being 172*F in 3 minutes from a cold start. The 180* thermostats take longer than 3 minutes for the engine to react 172*F and will trigger a code. 190* t-stats should not be a problem, but there is really little to be gained from such a change.

 

My 99 runs around 180 degrees.

It currently has NO heat inside. I'm trying to track down the problem right now.