hey ive got a mostly stock lo3 and the fan switch is busted, i have wired up a switch so i can turn it on at will but my temp sens or my coolant temp guage is messed up so i had been just letting the fan run all the time. i just got into datalogging and i was watching my temp here the past few days and the car just doesnt heat up. i took it to get gas 12 miles away for my first datalog and the temp was cruisin at like 170 so i turned off the fan to let it heat up and in 10 miles it gained like 9 deg. crusin at 70 mph. on the wa back i left the fan off and it hit 185 when i shut her off, i thought these cars ran like 20-30 deg hotter then that? and even if the dude before me had put in a 160* thermo the car still should warm up past that right??

 

You are correct, I believe the temp stock on an LO3 is ~222*.

I modified the cooling on my LO3 by popping in a 180* thermostat with four 1/8" holes drilled in it. As long as I'm driving faster than ~40MPH or as long as the fan is on, I stay right @ 170* except on the hottest days.

This is not a bad thing as the ECM will advance the spark timing a bit when the engine is running cooler. Should have a few extra HP from running so cool, but if you want heat in the winter, that'll be a small problem. Emissions will also be a bit dirtier as a hotter engine will typically has lower crap coming out the exhaust. As I understand it, this is why GM decided to make these engine run so hot.

I gained a bit of power from changing the thermostat and running 93 octane. Next I need to program a new chip to further take advantage of the cool engine.

 

I just purchased a 170* thermo to put into my car and i am looking into the CSR digital guage fan/pump control unit.
okay so there are numerous tables in the ecm that are supposed to warm the car up to operating temperatures which should help the damn thing get up to operating temps, granted i got rid of the heat stove piping and went with an open element but with the stock thermo opening at 195* i would think it would get up past 180*, the hottest i have seen yet in WINALDL is 190*. im going to pop out this thermo and swatch it for my 170, see what happens..

 

If WinALDL says it's running cold, I'd believe it over instrument cluster gauges. You could have sensor problems, but probably not. My bet's on the thermostat because even if the fan were always on, it should run roughly what the thermostat temp is.

 

[QUOTE]Originally posted by PhLaXuS
[B]You are correct, I believe the temp stock on an LO3 is ~222*.

I modified the cooling on my LO3 by popping in a 180* thermostat with four 1/8" holes drilled in it. As long as I'm driving faster than ~40MPH or as long as the fan is on, I stay right @ 170* except on the hottest days.

So you're saying that after the thermostat closes at 180*which I think it does, doesn't it? and when you're driving at an operational temperature of 170* the four 1/8" holes gives you adequate water circulation? Aren't you worried about hot spots in the block that the temperature guage doesn't measure? The temperature sensor switch is directly mounted on the thermostat housing so it's going to be immersed in the coolant from the four 1/8" holes but what about everything else. The only other sensor would be the coolant fan switch on the block.
That last part was purely hypothetical B.S. but what if ?

 

NOTE: All cases below assume adequate airflow through the radiator at all times:

1.) I used to run a 195* thermostat and my temp was stuck right about 200*

2.) I moved down to a 180* and my temp stayed right about there as well.

3.) I then drilled four 1/8" holes in the180* thermostat. This was with the specific intent of always having some coolant flow to help reduce hot spots. The addition of the four holes netted me approximately 10* cooler operating temperatures.

I've not performed any real tests, but based upon what I've seen (plus a bit more not here) it appears that the four holes are not enough to cool the system on their own and thus only slightly delay the opening of the thermostat. A properly functioning thermostat will begin to open as the coolant comes up to the specified temperature. As I see it, if the four holes were enough to cool the entire engine, it would be the same as not running any thermostat. Since they aren't my t-stat opens @ 180* as it should, but when open it has 0.049" sq additional area in which cross-sectional flow can occur. Granted, I'm not the only one who's done this mod (I got it off of one of the guys here)...so maybe they have more to say on the topic. I've only been running mine for ~2 months.

 

I did the same mod, only I drilled 5 holes. I have a 180* thermosat. I usually run at about 190-220* depending on day or night (cooler air) Highway or city (air flow). But thats O.K. because I know the thermostat is wide open and there should be ample coolant flowing through the motor. Even at 220* thats normal operating temperature for any normal-slightly modified engine. It's even lower than what GM expected these motors to run at. There are a lot of posts of people trying to get under 220* . If that's the hottest your motor ever runs, time to move on to the next problem or start enjoying their rides and quit worrying.