140F thermostat
 

Does anyone have any experience with the 140 degree thermostat that chevrolet puts in their marine 350 motors 1998 and later? Would it be good for an automotive application? Would it be better than the 160 everyone is using? Any advise? Would like to use it on an LS motor.

I've never even heard of a 140 tstat :eek: hopefully someone on here can help

I don't know about the 140 thermostat , But I do have a 160 in my 1940 chevy it runs fine.

i would stick with 160 and you should be fine

140 is too cold unless your compression is through the ****ing roof and mega boosted

And don't expect your heat to work either

;)

Can you clarify the application you want to use this with more?

LS motor meaning a v8 LSx? Or LS meaning your Monte Carlo LS which is a 3400. Which if that is the case I wouldn't go less than a 180 degree

thermostat
 

It's a LS7 V8. Having low speed temperture difficulties and was just looking for another cooling enchancement and I have been doing some research and found the 140F thermostat in Chevy motors in various marine applications and was wondering if anyone had any experience with one. Currently using a 160F and I am constantly running at 205/210 and that troubles me with tranny temps near 225. This is all at 40 MPH or less.

Wow, you shouldn't have that high of temps with that tstat. Bleed your coolant system, make sure the mixture is good, make sure you have enough coolant. My 180 tstat has me running at 179.

Is your car tuned in anyway shape or form for the new thermostat? Or are the fan speeds still set to stock?

If you just change the thermostat, you are just changing the point that fluid runs through the block. But if the fans don't come on until over 200, what's the point unless you are doing 100% highway driving with no air blockage.

Just bled the system and am running 40/60 mix. Going to 30/70 to see if that helps.
The fans have been retuned to match the thermostat as best it can. The stock PCM only allows for limited changes for the fan to come on and off. If I remember correctly on high the fans come on at 195F - driving temp goes up to 205/210 and stays there.