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'09 f-150 thermostat replacement 5.4L V-8


magpi1
09-13-2020, 10:17 PM
Hello,
I will be doing an engine flush on my truck and since it has 145k on it I want to go ahead and change out the thermostat too. not sure what degree the stat is, so 2 questions I have.

1- what is the degree on the stat in the truck now?
2- can I put in a lower degree stat so it will run cooler?

2009 f-150 Lariat 5.4L V8
Thanks for any help.

OK, MAKE THAT 3 QUESTIONS. SPARK PLUGS--WHAT KIND? SAME ENGINE.

Stealthee
09-14-2020, 12:56 AM
A cooler thermostat won't really make it run cooler and even if it did it's not better. Modern engines are designed to run optimally at anywhere from 190-210. Even with a cooler thermostat your fans are not going to come on until their set temp so you're still going to see stock temps.

Stick with oem type plugs. Also even though your truck is supposed to have the updated plugs good luck. The 5.4 is known to be a nightmare.

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