from what i understand our trucks came with a 195 deg t-stat. I went to change mine aqnd the old on is 180. I think the truck still gets to operating temp it just takes longer because the t-stat opens sooner. correct? Does this affect gas mileage?

 

Is there a reason why you want to go 180?

195 gives better MPG, but not by much.

 

usually my gauge stays near n. a few days ago it went up to the a. I figured a t-stat is cheap so i got a 195. I pulled the old one out and it said 180. the p/o changed it i guess.

 

I put in a 180* Tstat in my 89, and my mileage dropped from 10mpg to 7mpg!!!



Of course at the same time i pulled off all the emissions, added 37" tires, added long tube headers and lifted it! lol

 

The engine will also last longer with the 195 as you do not wash as much oil off the cylinder walls and contaminate the engine oil. The computer will also operate on different strategy tables.

 

how does the lower temp t-stat wash the oil off cylinder walls?

 

The computer will be using a richer table and the extra fuel in the cylinders will do it.

 

only if your piston rings are already garbage

 

Not sure what the piston rings would have to do with it. The piston and rings are down at the bottom of the stroke with the walls exposed.

 

theres always fuel up there anyways, and almost no oil on the upper cyl walls when the piston fires (the oil control rings scrape off the excess oil and keep it below the rings). the only time youll run in to trouble is if gas gets into the crankcase which would be from failing oil control rings. granted a rich running condition can cause gas to seep past the rings if theres too much of it. certain engines require 180 degree or lower thermostats, such as i know lew's drag truck is using a 160 and im going to be using a 180 or 160 in my drag car, but in the end, for a stock vehicle just use stock parts and use a 195

 

On some truck with the "oil cooler," a 180* t-stat makes sense. I am thinking about putting one in the '96 for that reason. I put a 180* stat in my car... It still averages 25 MPG like always.

 

The computer gets into closed loop mode right around 180, so fuel mileage shouldn't change by much compared to a 195 degree thermostat. I have used both and there isn't a noticeable difference in fuel mileage at all. The warm-up enrich progressively fades as the engine warms, so even if it is still active at 180°, it will not simply cause a too-rich mixture.