Martian

Hey all, I figure since my truck's got about 130,000mi on it now, changing the thermostat while flushing the cooling system wouldn't hurt it. It's only a $10 part anyway. But I noticed there are thermostats for 170F, 180F, and 195F, all listed as being for the 2005 F150 5.4L. The 195s say "OE recommended temp" on them, but from here I can't tell if that's just a marketing statement. Which temp is best for these engines, in reality?

Martian

Shameless self-bump.

Z7What

There's no marketing statement when it comes to TStats. The temp there listed at is the temp at which they open. Your truck comes with a 195* and that's what I would replace it with. UNLESS you have a custom tune that a tuner can make adjustments for the lower temp setting.

Going with a lower than OEM temp without tuning for it cause cause a few issues the biggest is mpg loses. This is because these trucks have what's called open and closed loop systems. When you first crank your truck up its in open loop, it's in open loop until it's up to operating temps then it switches to closed loop. If you put a lower temp TStat in without tuning the truck will never get to 195 operating temp and stay in open loop.

Hope this helps. Google open and closed loop to understand more.

Wayne

Martian

On that note, why do other companies (Gates, Motorad...) sell thermostats for 195*F clearly saying they're "OE Temperature" while Motorcraft's are all at 190*F?

techrep

iTrader: (1)

Buy OEM and you will eliminate all questions...

Z7What

My guess is that the 5* difference isn't a issue. You 100% sure your stock is 190* I have changed some TStat on 03s that are 192*. I'm sure that small different isn't even a concern, going 15-20* is.

Wayne

dnlow

I have a 2005 with the 5.4L engine and I sometimes have my scanner on it while driving and the coolant temperature is 195F but I do think that going with the Motorcraft thermostat is the best way to go.

Z7What

Although Motorcraft is great, I see no reason not to get a Stant. There just as good, just make sure it's the same temp as OEM.

Wayne