What is the advantage to putting a lower rated thermostat in my truck? Will it keep the engine temperature lower?

 

What year and what engine? The later model 5.4 engines need the hotter temps for optimum performance. They come with 192 thermostats but for performance, some run them between 200 and 210.

 

Unless its pretty much a 'race only' truck, I wouldnt put a lower tstat in. Lower temp tstats can end up as a PITA in computer controlled vehicles like ours. Id just stay with the stock 192 degree tstat.

 

There is no advantage. Mod motors tend to run a little warm, this minimizes sludge buildup. And in extreme conditions, running a cooler thermostat may prolong open loop operation or not allow the engine to go into closed loop at all, resulting in poor performance and worse fuel economy.

 

It's an 88 with a 5.0 bored 30 over. It's got a stock stat in it but I was thinking of replacing it with a little lower one. I guess if it's not good for the engine I won't do it. Thanks for all your feedback

 

Ahhhh, if its that old its a bit of a different story. We all figured you were talking about the modular motors (4.6/5.4)

How low are you thinking?

 

I'm not sure how low i should go....whatever helps bring my temp down.

 

What temp is causing you concern?
Runing to much cooler than about 185 will be detected by the ECT and run the base fuel tables richer.
This in turn can cause more carbon build-up in the EGR system as well as more contaminates staying in the crankcase, less heat from the heater in very cold weather.

 

if your engine is over heating then the stat will not help. There is no gain with lowering the opening temp of the stat. You will lose mpg, heat in the winter, and increase emissions (might fail inspection).