Which thermostat?

[JJ_lkey]

I'm changing the thermostat in my 96 Ranger 4.0 and I'm wondering if I should switch to the 180 degree or keep it at the 195. Has anybody seen any
improvements ie. hp increase/ fuel mileage increase etc.

 

[sholzy]

Depending on which parts store you go to, the correct t-stat is 192*, 195*, or 198*. I put in a 198* and it's too hot. I'm trying to find one that is closer to the 192* I had in it before.

180* t-stat is not good because the engine may not get hot enough to keep moisture from collecting in your crankcase. Your fuel mileage may go down with a colder t-stat because the ECC will think it needs to make the fuel mixture richer to bring the engine up to the correct temp.

 

[Big Jim M]

Around here the 195* is what is carried by most parts houses. That's what I put in everything.
Since the varience between 192 and 198 is only 6 degrees it shouldn't make any real difference to the engine coolant.
I'm sure the temperature varies much more than that from stoplight to stoplight. As long as the thermostat will open wide enough to allow full flow in the case of ultimate hard use either of them should be ok. If I had a choice of the three I would always choose the 198*.. I like em as hot as I can use em.
Big JIm

 

[nitrofan1]

Stay with stock. 180 & 160's do nothing for you except give you long term problems. The coolant temp sensor lets the ECM know what the water temp is. The ECM then determines air/fuel mix ratio which in turn the EGR system reacts to the air/fuel ratio when too much raw fuel is let into the exhaust system.

The result is your engine doesn't heat up to specs, you use more fuel, less MPGs, long term damage to O2 & cats, and as stated in previous post moisture in the crank case.

If you are determined to use a colder stat you will need to reprogram the ECM via a tuner programer or other means.

 

[JJ_lkey]

Thanks guys, Napa carries only the 180 or 195. They told me the engine temp with the 180 will run about 185-190 and the engine temp with the 195 will run about 200-205 not sure this is true or not. I always thought the sweet spot for engine temp was 185-195????

P.S. I'm putting this engine back together after replacing lifters/ heads. One of the reason's I was asking about engine temp/ thermostat was because the lower intake had a large amount of carbon bulid up and I'm trying to avoid this again. I usually ran 87 octane and most of the 150k is highway miles. I drive about 100 miles a day round trip so I'm looking to up the mpg.

 

[Big Jim M]

Weak spot

Thanks guys, Napa carries only the 180 or 195. They told me the engine temp with the 180 will run about 185-190 and the engine temp with the 195 will run about 200-205 not sure this is true or not. I always thought the sweet spot for engine temp was 185-195????

P.S. I'm putting this engine back together after replacing lifters/ heads. One of the reason's I was asking about engine temp/ thermostat was because the lower intake had a large amount of carbon bulid up and I'm trying to avoid this again. I usually ran 87 octane and most of the 150k is highway miles. I drive about 100 miles a day round trip so I'm looking to up the mpg.

The weak link in the cooling system is the coolant that has water in it. The water will boil at about 235* with a 16 lb cap on the radiator. The engine would LIKE to run at 235*! So would the oil and the fuel.. But as stated the weak link is the water.
So we are limited to keeping the temp below 235* by that water. Since the coolant pump will pump about 50 or 60 gallons a minute and there is a powerful fan pulling air thru the radiator to cool that coolant the actual temperature of the engine is moot.
I betcha all modern engines of all makes run at 205/210*.. So by all means put the hotter thermostat in there.
Remember it isn't the engine that will complain... It's the water in the coolant.
I run pure ethylene glycol in my rides..no water.. so my coolant won't boil until over 400* The engine likes that stuff. It won't do in the far north as it freezes at around 0*.. But here in Austin it does fine.
Big JIm

 

[kimcrwbr1]

You have to be aware of how the engine oils also running it too cool will cut down on bering life also they are designed to run hot.

 

[jhammel85]

My votes for stock 195

 

[sholzy]

According to my local Ford dealer yesterday, my '93 came from the factory with a 197* t-stat. They list alternates as 192* and 190*. They said anything colder than the 190* and the ECC could have fits.

 

[nitrofan1]

According to my local Ford dealer yesterday, my '93 came from the factory with a 197* t-stat. They list alternates as 192* and 190*. They said anything colder than the 190* and the ECC could have fits.

Yup