Thermostat chat, Ranger temp obsession (let's split some hairs)

[Eddo Rogue]

After much search and reading, I am still a indecisive about what thermostat to run. So many options! Before my thermostat collection gets out of hand, figured I try to get some recent opinions....

I am currently running a motorcraft 195 degree...it has the jiggler, not sure if its fail safe....or that I wanna stick w/ it in the coming hot summer months.

I definitely want one that is fail safe and has the bypass "jiggler", but have some questions....

Is there any benefit to NOT having a fail safe? Is it just cheaper? or does it flow more/better or something? Same w/ not having the bypass jiggler...

Will a lower temp thermostat (180) better protect my heads from excessive heat?

Why is there so many temp differences for the 190 range thermostats (190,192,195,198 etc)?

what are the pros/cons of 180 vs 190-198? as well as the jiggler/fail safe options?

What do you run and why?

 

[Dirtman]

Lower temperature thermostats do not make the engine run cooler nore will they protect it from overheating. Use an oem thermostat and don't think about it anymore.

I HAVE SPOKEN!!!!

 

[sgtsandman]

The jiggler is there to allow any trapped air to purge. It’s not really a fail safe.

The whole engine management system is set to look at a specific temperature range to regulate everything. Emissions, timing, idle speed, transmission shift timing with automatic transmissions, etc. on newer vehicles it is best not to mess with the temperature range of the thermostat. The newer the vehicle, the more critical it is.

If you are worried about over heating, it shouldn’t be an issue if the cooling system is functioning properly.

For the above reasons, I stuck with the factory thermostat when I changed mine. The old one was starting to stick a little bit. I knew that only because my Scan Gauge II is setup to display real time engine temperatures.

Now, this is my experience in Southwestern PA. We sometimes get into the 90s and the humidity can get pretty high.

Your experience in Southern California (at least I think that is where you are from) might be a bit different. Higher temps but lower humidity.

 

[sgtsandman]

Lower temperature thermostats do not make the engine run cooler nore will they protect it from overheating. Use an oem thermostat and don't think about it anymore.

I HAVE SPOKEN!!!!

 

[sheep herder]

Damn! The Dirtman is correct. If you have an overheating problem, putting a lower temp thermostat in it won't fix the problem.

 

[cbxer55]

This always happens when discussing thermostats. I am running a 180 in my 98 V-6 Ranger. Been doing so since I bought it in January 2000. Never a problem. The stock thermostat on my Lightning is a 180, I run a 170. I also run a 180 in my 2007 Mustang. On all these vehicles, where the temperature needle used to point dead center, normal for stock thermostat, all of mine read south or left of center by a noticeable amount. No check engine light, no codes.

I've always done it and I always will.

 

[97RangerXLT]

the manufacturer put the 195 degree stat in there so the engine will run more efficiently. (hotter it runs, the more efficient it is, within reason) the engine was designed to run with that tstat. As mentioned above, if you have an overheating issue, the tstat is not likely the cause unless it is old, sticking and just needs to be replaced with a new oem spec tstat. going lower will not make the truck run badly, it just won't run at the optimum efficiency of the engine, and the computer will adjust the fuel air mixture to suit. this will likely drop you a few mpg in fuel, but probably the only noticeable effect of running a cooler tstat.

AJ

 

[cbxer55]

Well, with the exception of the Lightning, which is the only vehicle I've ever owned where you can watch the fuel gauge move, my Ranger and Mustang do pretty well on mileage. The Stang is a 4.0 V-6 auto, currently the dashboard is showing 23.8 mpg. And that's a lot of around town driving, on a modified exhaust (all three inch dual, custom done before I bought it) and intake and a 93 octane tune. The 3.0 Ranger has always run around 18 to 19 in town, a hair over 20 highway. It does have 3.73 gears, which are not really mileage gears after all. LOL!!

All my vehicles are autos, and the first thing I do in all of them after the engine is running, is click off the OD. I don't turn it on unless I hit the highway or speed is north of 50 mph. The Mustang has a readout of the mileage, and OD on or off doesn't hardly affect it at all. Maybe .1 or .2.

 

[85_Ranger4x4]

I started off with a 160* thermostat per someone on here's recommendation for a V8 swap, the only thing it accomplished was pathetic heat in the winter. Engine still ran around 200* in the summer.

It now has a normal replacement 190-195 stat in it. No jiggler and hodge-podge system was a PITA to bleed so I drilled a 1/8" hole in it and it is now a breeze to fill.

 

[RonD]

Upper engine thermostat of 190-195deg will get better MPG, not even debatable just science and facts in tests
Long term it should keep the oil cleaner as well, but engine life and oil change intervals its hard to say that's a fact, on paper and tests it does show that

Lower engine thermostats are 180deg, which keeps upper engine at the 190-195 range

Difference in overheating starting at 180 or even 200deg is about 5 seconds, so if there is a cooling system issue thermostat temp is a moot point, lol
They would BOTH be open all the way at that point

The radiator is there to dissipate EXTRA heat the thermostat temp decides when there is extra heat and then allows flow thru the radiator to dissipate that extra heat
A Thermostat is a variable valve, not OPEN/CLOSED, it opens enough to dissipate extra heat then closes as needed
In the winter in some areas the radiator is not even used with some engines, hard to even keep them at 190deg

If your engine runs warmer than you think it should then that not a thermostat issue, there is a problem in the cooling system
All engine thermostats are made to "fail safe"(stuck open all the way), but it doesn't always work, it depends on what part fails

 

[19Walt93]

The thermostat only controls the lowest temp the engine will operate at, the cooling system has to control it beyond that. Is the radiator in good shape and clean? Not just inside,m mud covered cooling fins won't dissipate heat. If it has a fan clutch does it engage? If it's an electric cooling fan does it work?

 

[8thTon]

The hotter the radiator the greater the temperature difference between it and the air, so the greater the heat transfer. The cooling system capacity was determined with a specific thermostat, by putting a cooler one in you are reducing its heat transfer rate.

 

[ford4wd08]

Upper engine thermostat of 190-195deg will get better MPG, not even debatable just science and facts in tests
Long term it should keep the oil cleaner as well, but engine life and oil change intervals its hard to say that's a fact, on paper and tests it does show that

Lower engine thermostats are 180deg, which keeps upper engine at the 190-195 range

Difference in overheating starting at 180 or even 200deg is about 5 seconds, so if there is a cooling system issue thermostat temp is a moot point, lol
They would BOTH be open all the way at that point

The radiator is there to dissipate EXTRA heat the thermostat temp decides when there is extra heat and then allows flow thru the radiator to dissipate that extra heat
A Thermostat is a variable valve, not OPEN/CLOSED, it opens enough to dissipate extra heat then closes as needed
In the winter in some areas the radiator is not even used with some engines, hard to even keep them at 190deg

If your engine runs warmer than you think it should then that not a thermostat issue, there is a problem in the cooling system
All engine thermostats are made to "fail safe"(stuck open all the way), but it doesn't always work, it depends on what part fails

I never thought about upper vs lower.

My 85 2.8 has the thermostat on the timing cover down at the lower part of the engine, should I be running a lower temp one than say someone with it up and the intake manifold elbow?

 

[cbxer55]

The hotter the radiator the greater the temperature difference between it and the air, so the greater the heat transfer. The cooling system capacity was determined with a specific thermostat, by putting a cooler one in you are reducing its heat transfer rate.

So that's why the temperature gauges on all three of my Fords all point to a lower point on the gauge than normal center. It's not working as well. LMAO!

All three used to point dead center. Now the Lightning and Ranger are noticeably below center, and the Mustang which used to point center is now well left of center. And don't tell me the gauge isn't accurate. It goes from below C to operating range within five minutes. Then shut it off for ten minutes and it's considerably down. So if the gauge needle is pointing lower, the engine is running cooler.

You guys do what you like, I'll keep doing the same. It's never hurt a thing on any of my vehicles. Ranger has had the 180 since like March 2000. One of the first things I did after buying it. That and the MAC intake. Same with the Lightning, same with the Mustang.

 

[RonD]

If the thermostat is on the upper rad hose you use the higher temp
If thermostat is on the lower rad hose you use the lower temp

Many 4cyl engines and transverse mounted engines use lower radiator hose thermostats

Radiator has no circulation until the thermostat opens a bit, doesn't matter which hose it is on