Community Forums

Floyd2u · 09-14-2021, 07:36 AM

What are your thoughts on going with A 180o thermostat?

thanks
Floyd

yeloduster · 09-14-2021, 08:01 AM

Your computer controlled engine is designed to operate at 195F. If you lower the thermostat the computer thinks the engine is a little cold and adds more fuel to compensate. I think you will only notice the difference in your wallet at the fuel pump. Lowing the operating temperature will probably increase your fuel consumption.

Engine temperature is a balancing act. Hotter engines are more efficient because the fuel atomizes better, ignites better and burns more completely. GM engineers think the 8.1L engine runs best at 195F so they programmed the computer to optimize operation at that temperature.

I will leave mine at 195F. I'm not opposed to modifications. I do it all the time and if I could justify the expense I would add headers and maybe a cold air intake. Higher ratio rocker arms might make her breath better and modification to the intake manifold have proven to be effective. All cost more than I am willing to spend. On the other hand, I think Workhorse motorhomes are geared too high for continuous mountain use like I do. I'm considering going from a 4.88:1 differential gear to a 5.38:1.

MinntoMich · 09-14-2021, 09:30 AM

I have a 454, not an 8.1 and I went with an alternate thermostat. Thought the MH ran too hot, especially when working the motor. I suppose that's the case for everyone but it made me uncomfortable.

This is actually my first big block. The previous MH had a 360 and I also went with an lower temp thermostat there. I thought the clerk at NAPA made a mistake when he gave me the replacement for the 454 as it looked small in comparison to the thermostat in the 360, like it'd be better suited to a lawn tractor.

Don't know if your tranny cools though the radiator or if you have something else like an added cooler or a deeper pan, but I've been told heat is the number one killer of transmissions. That and always running hot was enough for me.

kennersonf · 09-14-2021, 10:54 AM

I switched to the 180 degree thermostat years ago and couldn't me happier. Number one, it does not cause more fuel consumption. Mine has stayed the same through the years. There is no loss in power and the engine runs just fine. The one thing you'll notice is that the centrifugal fan will kick in at a little lower temperature and slower speed resulting in less noise as it cycles in and out. Don't get me wrong. When it's hot outside or you're pulling a grade and the engine gets up to 200 and above, the centrifugal fan will spin at full force and full roar.

donr103 · 09-14-2021, 12:27 PM

Thermostat is cheap.. easy to change... experiment.. it's your coach.. on mine.. 2000 454 Chevy.. no cats.. cold air intake.. I run 160.. I don't use much in winter... so play around find out what works best for you.. yes if you had 1 million dollars in testing equipment.. you might be able to detect very tiny mpg difference.. we talking in relative terms 0..

The only reason the manufacturer put in 195 is to pass smog cops cooperate emission.. that is all.. and I had mine tested after adding 160 and still well with in limits..
The colder you can run the longer it will last.. only exception I found is those who run in deep cold.. just use good old cardboard to cover what you need to keep temp satisfactory..

Goggle oil temps versus trans and eng life.. make your own decisions.. experiment.. learn.. really most people don't care to keep that long or trade up.. because technology is changing so fast.. if you plan to keep.. run cold as possible..

Don't believe me? Read up on how 195 degrees thermostat came about.. why did most pre-emmision vehicles use 165 or 170.. good luck and let us know what you did and maybe better members then me will help you oh yes computer will adjust for colder thermostat.. but will do just fine..

dieselclacker · 09-14-2021, 05:44 PM

I have been running my 8.1 motorhome for 14 years with a 180 degree thermostat. The fuel mileage was not affected with its installation, nor was the engine performance. The amount of time and degree of engagement of the viscos fan was the main reason for installing it. The only negative side I have experienced is less heat from the dash heater. We don’t RV in winter much, so the trade off for a quieter operating fan is well worth it to me.
And yes, it will pass smog inspection