wilsonbh

I know it's not socially acceptable here to discuss this.... but now as it's really getting hot here in southern Florida, I ran my 94 Corvette yesterday, all day long with the A/C running, in stop and go traffic and the car never got above 188 degrees.

Before my swapping out the thermostat, it would hit 235 under the same conditions. I would pull over and run the car without the A/C for a little while to cool it off before I got back into traffic. When I would park, it would gurgle and boil over into the overflow from the heat buildup.

Now, in a colder environment, I suspect the hotter temps would be ok. But here in FL, it's not good...

So anyone sitting on the fence about this mod, I'm here to tell you that it's working for me!

Billy

runner140*

Yesterday I drove 55 min. on US1 which has many traffic lights, and stayed under 190. I have a simular set up as yours. It works.

BerniesVette

Did you have your chip flashed to change the fan settings or did you install a sender to turn your fans on earlier?
Bernie

Aardwolf

I don't know why it's not socially acceptable but it's reasonable to expect your car to run cooler with lower fan settings under 40 MPH and run cooler over 40 MPH with a cooler 'stat (to the limit of the radiators ability to cool).

SJW

It made a big difference in the ECTs on my '94, too. I'm really glad I did the change. I'll be doing this on the LT4 coupe ASAP, too.

Be well,

SJW

CentralCoaster

The key is the fan settings.

The radiator can't do much without the fan on. I think the fights start when someone starts saying the lower thermostat alone caused their car to run 180F across the board, or that 220F is going to cause their engine to self-destruct.

Just be sure your fan "off" temperature setting is sufficiently above your thermostat rating and your fan will last longer, instead of running all the time.

There's also a thread on the function of the overflow/expansion tank at the top of this section which explains how that works, and why the boiling is normal.

C4Techie

Running at 188* or " under 190*" has little to do with changing to a thermostat that is any cooler than the stock 180* stat. Once the stat opens, all it controls is the minimum operating temp. Not the max temp. At ~188* you have already exceeded the stock thermostat opening point. The 160* stat only serves to slow your warm up. The cooler low speed temps are due to fan reprogramming, not the stat change.

cv67

I like running 160s in my cars, no need for a heater out here. Like em running between 170ish and 185ish. Yes, reprogram your fans for the full effect.

SJW

This is correct (and also, I'm confident, why the OP titled this thread, "160 Thermostat and fan adjustments..."). The 'stat change allows the fans to be programmed for lower temps without running constantly at idle/low-speed, and permits cooler high-speed operation. The combination of 160* 'stat and lower fan-on/off settings is the key.

Be well,

SJW

CentralCoaster

There are also questions on how low the fans can actually pull the coolant temperature on a hot day at idle, (assuming the tstat is open.) This is the true measure of how efficient your cooling system is and can vary from car to car and with outdoor temps. My L98 with both fans are capable of pulling it down to at least 170F at hot idle in 75F temps, but I don't know how low it could go since my thermostat is closed at that point.

The LT1s with low stats and fan settings appear to ride against the thermostat yet the dash shows 20F higher than the tstat rating. Nobody's found out exactly why this is. If it's due to where the sensor is placed relative to the tstat or inaccuracy between the tstat and sensor calibration. It also implies the fan settings and thermostat operation overlap, so the fan could be running way more than it should.

This may be the first thermostat thread in history where everyone agrees (mostly). All those years of gratuitous insults and bitching are finally paying off.

Vette Gator

I've been following this and related discussions since I got my 89 last December. At some point in its previous life, it was modified so that both fans are always on whenever the car is running. It also had a 160 degree thermostat installed. Early on, I had a "Low Coolant" light issue that turned out to be headlight-induced wear on the side of the overflow hose between the radiator and overflow tank. After fixing this, the highest coolant temps I see are 170-180 and top oil temps are 175-185. At first, I was going to wire my fans back to the stock arrangement, but since I live in Central Florida, I'm leaning toward leaving it the way it is, at least through the end of summer. Apart from increased wear on the fans, I've noticed that the car doesn't perform too well when the outside temperature is below 50. At highway speeds, the max coolant temp I can get is 125, so the motor never really warms up. However, since it's really only a warm weather fun car, this isn't too big of a problem.

Aardwolf

Seeing temps stable below the 'stat temp would lead me think that the 'stat failed open. You may want to start saving up the money for new fan motors.

CentralCoaster

I haven't seen many complaints about fan motors going out, but a forum member's car that I worked on had a Hypertech chip tried to run the fan below the thermostat temp.

His fan motor eventually crapped out and caused him to overheat.

SJW

My LT1's ECTs will run ~10*F above the 'stat temp at highway speeds on all but very hot days. A few degrees hotter with ambient temps 80*F or higher.

With the 160*F 'stat installed, I have my fans programmed as follows:

Primary on @ 190, off @ 180

Secondary on @ 195, off @ 185

This works quite well, and the fan operation does not overlap with the 'stat operation. The 'stat is always open whenever either fan is running. I think this setup is just about ideal, and my newly-acquired LT4 coupe will soon be set up this way also.

Be well,

SJW

Fuzzy Dice

The only thing you have to watch is the oil temp...185 is barely high enough...most would say it is NOT high enough...experts have told me the oil temp needs to get over 205-210 for at least 30 minutes straight to get rid of the moisture that builds up in your engine...

I live in central florida as well and have a 160 stat...my fans are set to come on at 198 and go off at 192...this allows my oil temps to get over 210 regularly enough...

Vette Gator

Thanks for the heads up. I will keep an eye on how high the oil temperature goes as the weather gets warmer. I haven't run the AC yet, and I'm sure that this will also push my temps higher in the coming months.

SJW

I've heard this concern raised, too, but I've seen zero evidence of moisture buildup in the crankcase of my LT1 with it set up the way it is. It's worth bearing in mind that water will vaporize quite readily at temps north of 150*F -- it doesn't need to actually boil. Consider how quickly a few drops of water will vanish from the sidewalk on a 100*F day.

Be well,

SJW

CentralCoaster

Good description. Lower oil temps will take longer to burn off the moisture, but it will still burn off given enough time. Think about the marine layer on a morning at the beach.

Also, even though your oil sending unit might say 180*F, there are probably hotter areas in the motor. Water probably won't evaporate though in the pressurized areas. It needs the low pressure of the crankcase and top of the motor to do that. I'm guessing most of the moisture is burned off when the oil gets into the valve covers.