Thermostat Delete?

**ls1camino** · 10-23-2012, 04:50 AM

I have an electric waterpump with a SBC 160* tstat in a stock LS1 tstat housing. Since I removed the HVAC system, is there any reason to keep the tstat? The car is a street car that only gets driven during nice days. It is always allowed to warm up before driving, so I see no reason to have that restriction in the cooling system.

**2002ssslp** · 10-23-2012, 05:13 AM

Why do you want to run without a thermostat ? Your computer adjusts several things on your engine using the engine temp reading. I would at least run a 160 deg. Stat.

**ls1camino** · 10-23-2012, 05:36 AM

One less thing to fail. It is also a bitch to center in the waterpump it's a tstat not made for the LS1.

**RedFenix_68** · 10-29-2012, 03:30 PM

hey fuck it bro, let the frankenbird run free hahaha

**Spikito** · 10-29-2012, 05:53 PM

i was under the impression that without a t-stat, your coolant will reach an equilibrium thats too high....with a t-stat, water sits in the block until and heats up, while water sits in the radiator and cools, once it hits 160 in the block, the t-stat opens, the water switches places, once the cooler water makes its way back to the t-stat, it closes, and the cycle starts over...with no t-stat, water will just free flow through. I would think that after awhile, especially if sitting still, a free flow trip through the radiator wouldnt be able to cool adequately, and youd end up with a whole system of hot water

**2002ssslp** · 10-29-2012, 06:46 PM

A thermostat helps build coolant heat to a preset temp and maintains that temp. without a thermostat coolant is circulating all the time and it takes longer to build heat in the engine. The PCM montiors coolant temp and it sets the AF ratio for emmissions and the spark advance for economy. If you run without a thermostat you need to tell the PCM. Call Frost.

**ls1camino** · 10-29-2012, 07:07 PM

Thanks for the input guys...tstat will be staying put.

**Too Fast** · 10-30-2012, 02:45 AM

Yes keep the t-stat. Without one it can run too cool, and that wastes fuel. You said you have an electric water pump. Does it always run or does it only run on demand, that could act like a thermostat. However, I'd still like some coolant flow in the engine to not let any locallized hot spots develop.

And the best way to warm up any engine is with mild to moderate driving the first 5-10 minutes. Then go for it! Idling a vehicle to warm it up is a big waste of fuel, unless you like to hear the it rumble/lope. Some high performance ''M'' enigines in BMW actually have a tach with a moving red line, depending on how warm the fluids are.

**pajeff02** · 10-30-2012, 03:53 PM

You can ditch the stat and run a restrictor -- essentially a large washer in place of the thermostat. The restrictor slows the flow of water and comes in various diameter holes. We ran one in our circle track car without any issues and it held consistent temps. Benefit of not having a stat is that it can never stick on you and overheat the engine.

**ls1camino** · 10-30-2012, 05:41 PM

Originally Posted by pajeff02

You can ditch the stat and run a restrictor -- essentially a large washer in place of the thermostat. The restrictor slows the flow of water and comes in various diameter holes. We ran one in our circle track car without any issues and it held consistent temps. Benefit of not having a stat is that it can never stick on you and overheat the engine.

Hmm...never heard of this before. Like I said, I don't need the tstat failing on me. Also, since the Meziere Water Pump uses a SBC tstat, I bet I can find a restrictor for it.

**pajeff02** · 10-30-2012, 06:15 PM

Absolutely. Here's an offering from Jeg's: Mr. Gasket 6126 Mr. Gasket Water Outlet Restrictor Plate Kit

**ls1camino** · 10-30-2012, 06:41 PM

How does that work? Different openings provide different engine temps? Is it a trial and error thing?

**Too Fast** · 10-31-2012, 02:19 AM

Yes exactly, different size holes give different temps, they might be able to give you a guidline for which one to use first. You don't want one with too small an opening, that might be fine for around town but on the highway or when you are having fun with the car it may be too small.

I still vote for you to keep the 160* t-stat. You really don't want to run any cooler than ~165, and a restrictor that might work for fun driving could allow too cool for more legal driving.

**pajeff02** · 10-31-2012, 02:46 AM

Try the middle size and see how your temps run. Or, take a look at a stock 'stat and match up the hole size as best you can. The restrictor slows down the flow and allows the coolant to do its job efficiently -- absorbing the engine heat and dispersing it through the radiator's airflow.

**JayTA98** · 10-31-2012, 01:46 PM

interesting topic.

**SuperSSguy** · 10-31-2012, 05:37 PM

Originally Posted by 2002ssslp

A thermostat helps build coolant heat to a preset temp and maintains that temp. without a thermostat coolant is circulating all the time and it takes longer to build heat in the engine. The PCM montiors coolant temp and it sets the AF ratio for emmissions and the spark advance for economy. If you run without a thermostat you need to tell the PCM. Call Frost.

So in your opinion do you think a 160 degree will increase emissions over a factory t-stat?

**Too Fast** · 11-01-2012, 02:40 AM

If your running too cool, yes you will increase emissions. Below about 165* most PCMs will run on tables that ignore the O2 sensors, therefore not fine tuning the fuel table. So wasting fuel equals less MPG. One of the first things I look for when someone comes in saying their car is getting worse then usual MPG is to see if the t-stat is working correctly.

So if you are constantly running too cool, then yes you are burning more gas, possibly having the rich mixture more quickly contaminate the oil since more fuel is blowing by the rings, causing more engine wear over the long run, causing your converters to work harder, etc.

**pajeff02** · 11-01-2012, 02:42 AM

Open Loop / Closed Loop is somewhere around 120 to 140 degrees on our cars, if I recall correctly. Even with a 160 degree thermostat, the engine will generally run warmer than that by several degrees. With a 180 degree thermostat in our car, and reprogrammed fans, the temps stay between 186 and 192 on average.

**ls1camino** · 11-01-2012, 04:08 AM

Originally Posted by Too Fast

If your running too cool, yes you will increase emissions. Below about 165* most PCMs will run on tables that ignore the O2 sensors, therefore not fine tuning the fuel table. So wasting fuel equals less MPG. One of the first things I look for when someone comes in saying their car is getting worse then usual MPG is to see if the t-stat is working correctly.

So if you are constantly running too cool, then yes you are burning more gas, possibly having the rich mixture more quickly contaminate the oil since more fuel is blowing by the rings, causing more engine wear over the long run, causing your converters to work harder, etc.

What is a converter?