wich thermostat? 180 or 195 degree?

adambant · January 31, 2011

i have a 99 4.0 SOHC that i replaced plugs wires air filter coolant, and a 180 degree thermostat a few weeks ago when i replaced all my chain guides and cassettes. I didnt notice where my temp gauge sat before all this but now it sits just a hair below the water temp symbol on the gauge, not the middle of the gauge. this seems low to me and ive been getting only about14MPG's. Should i swap in the 195 degree thermostat? is that the stock temp? any thoughts on this? thanks!

Adam.

Turdle · January 31, 2011

You answered your own question didn't you--

Yes, you want the 195 thermostat. The ECM will not function in "closed loop" until the coolant reaches 195

adambant · January 31, 2011

Turdle said:
You answered your own question didn't you--

Yes, you want the 195 thermostat. The ECM will not function in "closed loop" until the coolant reaches 195

Thank you! yea i was fairly certain this was the case, but i still wanted some confirmation b4 i went playing in antifreeze out in the cold

Thanks turdle!

2TimingTom · January 31, 2011

Yep- 195. It's possible the ECU is staying in open-loop mode longer due to the lower temp thermostat- thus resulting in bad mileage.

edit: whoops- man I really didn't read the first reply well enough......

mistertonylee · January 31, 2011

Yeah. I always thought my explorer had really bad fuel economy. The temp. line would get just over cold. 195 degree thermostat, and +3 mpg.

adambant · January 31, 2011

mistertonylee said:
Yeah. I always thought my explorer had really bad fuel economy. The temp. line would get just over cold. 195 degree thermostat, and +3 mpg.

I would be ecstatic if i get +3 mpg!

So i stopped at advance on the way home and was robbed for 18.99 for the 195 degree Stant thermostat. Why on earth is this thermostat 19 bux?! Anyway, it's in the truck now. I took a picture of the temp gauge with the new t-stat and at operating temperature. It definitly moved up some, but maybe im over analyzing it but it seems to me that it should still be a little "hotter" to be in the middle? The red line is about where it was before, with the 180 degree T-stat. How does this compare to your temp gauge? Am i worrying to much about this?

mistertonylee · January 31, 2011

Hey. Hope it'll still improve your economy. Wish I had that much gas in mine! My thermostat was stuck open, so it was here.

Of course, without numbers on the dang gauge, I don't know if that was 80 deg or 175.

adambant · January 31, 2011

Yea I would LOVE numbers on the gauges! Would be so much more useful that way. I think my Voltage is a tad low as well, but that wouldnt surprise me, as my alternator is making such a nice "howl" we'll say, letting me know its on (and has been) on borrowed time. Im waiting for it to blow before i replace it, partly watching my $ but also just wanna see how long it'll go like that lol. When i get paid next week, i will buy a new one, and just keep it in the back of the truck with my tools, that way i won't be screwed when it siezes or blows on me.

The gas in my tank.....Ive only gone 110, 99% highway miles cruising at 70 mph since i filled up, and thats all i have left! So you can see why i need this t-stat to do somting for me

Also changed my front and rear diff as well as transfer case fluids last week, not synthetics though, i was to broke for that.

Also gonna up my tire pressure to 38 PSI. I was running 35, but didn't realize till i checked today that last week when i got an alignment and tires balanced, the shop dropped my tires to 32 psi all around....grrrr.

joe doe · January 31, 2011

looks perfect where it is now .stop obsessing now..lol

239 · November 26, 2018

My coolant temp stays at 180 and sometimes as low as 170 but it still goes into closed loop mode. I’m running a Motorcraft “190” thermostat at the moment but I’ll be replacing it this weekend. I think I may have received a defective unit last time. Strange thing is I get great gas mileage too.

donalds · November 26, 2018

adambant said:
Yea I would LOVE numbers on the gauges! Would be so much more useful that way. I think my Voltage is a tad low as well, but that wouldnt surprise me, as my alternator is making such a nice "howl" we'll say, letting me know its on (and has been) on borrowed time. Im waiting for it to blow before i replace it, partly watching my $ but also just wanna see how long it'll go like that lol. When i get paid next week, i will buy a new one, and just keep it in the back of the truck with my tools, that way i won't be screwed when it siezes or blows on me.

The gas in my tank.....Ive only gone 110, 99% highway miles cruising at 70 mph since i filled up, and thats all i have left! So you can see why i need this t-stat to do somting for me Also changed my front and rear diff as well as transfer case fluids last week, not synthetics though, i was to broke for that.

Also gonna up my tire pressure to 38 PSI. I was running 35, but didn't realize till i checked today that last week when i got an alignment and tires balanced, the shop dropped my tires to 32 psi all around....grrrr.

How to: - 4g alternator rebuild with pictures

koda2000 · November 26, 2018

SOHC thermostats are expensive. I bought an aftermarket SOHC t-stat at O'Reilly's for around $18 and it ended up it stuck and I returned it for a Motorcraft t-stat. The Motorcraft t-stat at O'Reilly's was $32, but at least it works.

When I bought our '00 Mountaineer 5.0L AWD it had a t-stat that was stuck open. On the way home it got 13 MPG. After replacing the t-stat with the recommended 195 degree t-state the mileage went up to 17 MPG and I even squeaked out around 21+ MPG highway once. As said, you have to get the engine hot enough to enter "closed loop mode" or it's like driving with the choke on.

wich thermostat? 180 or 195 degree?

adambant

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Turdle

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adambant

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2TimingTom

mistertonylee

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adambant

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mistertonylee

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adambant

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joe doe

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239

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donalds

koda2000

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