so I run a 180 thermostat with a radiator out of a 5.0. my temp gauge sits half way between the c line and the normal half way point. is that too cold to run it or is it actually better for the motor? I know my gas mileage will suck, but I don't care about that. attached is a pic of where it usually sits. sometimes once ive driven it for a while it sits up a tad more. opinions everyone?

 

You will get slightly more power and slightly worse mpg, probably not enough of either to notice. Your engine don't care.

 

Engines today are very particular as to what temperatures they operates at. The days of running a colder thermostat because we think "it is better for an engine to be cooler" is no longer the case. Most engines (including the Ranger) use two engine coolant sensors; one for the guage, and one for the engine management control (PCM or ECU). The engine mapping parameters are adjusted based on engine temperature, amongst other input readings.

RonD posted a good reply to this on another thread explaining the Ranger cooling system. Excellent write up.

I keep my Ranger with the stock thermostat setting. It has 215K of reliability so far; no reason to second guess the cooling temps.

 

+1 ^^^^

S.A.E.(society of automotive engineers) and Ford did some advanced testing on engine temp and oil back in the '70s.
Through SAE testing it was known prior to this that running an engine above 160degF was better because at that temp moisture(condensation) in the oil would start to "burn off" and some fuel contamination(blow-by) would "burn off", this is why we use a thermostat in the first place.

What the advance testing found was that at 195degF there was better "burn off" in the oil, so less contaminates circulating with the oil.
That is when Ford switched to 192-195degF T-stats.

The "burn-off" curve peaks at about 195degF, running at 180degF is better than 160degF but not as good as running at 195degF.
192-195degF t-stat means cleaner oil, and cleaner oil means longer engine life.
Added benefit is better engine efficiency so better MPG

The thermostat sets the MINIMUM operating temp of an engine and has nothing to do with an engine overheating, even on a HOT day or long uphill drive, lol, t-stat is not part of that, your cooling system gets rid of excess heat via radiator, air flow and circulation, so a problem in one of these would be the cause of overheating.

Above is based on UPPER rad hose thermostats, some vehicles use LOWER rad hose t-stats, these use 180degF t-stats because UPPER engine will be at 195degF when lower engine 180degF t-stat opens, just FYI.

 

Isn't the temp gauge just a glorified idiot light .

It reads one setting most of the time or hot when it is hot.

So is the position of the temp gauge really important.

If the gauge is not where is used to be, it might be an electrical issue.
Bad ground on engine, corroded connections.

Or is the sending unit the same resistance as the engine the 5.0 replaced !

You need to find the actual temp of the engine when you think it is hot, then decide from there what is wrong.

Where I am going with this is, it isn't always the t-stat that is the problem.

 

I suspected this, as I read it on other forums as well. However, I installed an e-fan a few months back, and had the engine running to adjust the e-fan's temp sensor that triggers the relay to set the hi speed fan on (two speed fan; low speed for A/C, and high speed when engine reaches a certain adjustable temp). After about 15 minutes, I noticed the radiator was beginning to gurgle, and I saw some radiator coolant coming out from a radiator fitting, yet the guage never moved past the center mark (between cold and hot). Longer story shortened, I purchased a new engine cluster temp guage sensor, and the guage now works correctly (the temperature will climb past the halfway mark if the fan does not come on after about 195 to 200 degrees).

Easy test of the temp gauge sensor (remember, there are two; one for the guage, the other for the engine management system). Remove the wiring plug from the sensor used for the guage cluster (this plug will only have one wire instead of two, even though the sensor has two prongs). Turn the key to "on" (don't start the engine) and ground this wire; the guage in the cluster will peg hot. Remove the ground, the guage will read cold. If that works, the wiring and the guage are good; replace the sensor.

 

rangerstepside,

If your truck is jacked up, suspension not juice, and you are running hot try lifting the rear of the hood about an inch, sort of a poor mans crowl induction.
This will release under hood pressure and will drop the temp some.

My 88/5.0 Ranger ran hot on the highway but ok in town, per an AutoMeter Gaige and sending unit.
The faster I went the higher the temp to a point, the truck never overheated.
At the suggestion of a Ford Emgineer, I jack the rear of the hood up one inch and the temp dropped 10+ degrees. He claimed the lifted condition of the truck caused excessive pressure on the engine bay from underneath the truck and did not let air through the radiator, so it didn't cool properly.

Funny but he was correct in his assumption.

If you are still running hot after all on your investigation, lift the rear of the hood and see if it helps.

 

No, the Ford oil pressure gauge after 1985 is what you are thinking about.

Temp gauge reflects actual temperature based on resistance in the Sender.

Oil pressure is an on/off switch, not a true sender

 

thanks for the reply guys. all good info. yes the temp gauge IS actually a temp gauge. and no there is no idiot light. my truck ran normal with the 195 thrermo in it. as in the needle was right in the middle, even with my 5.0 rad. but my logic was less heat/less wear. instead of having my truck run a constant 195 I was gonna run it at 180. I know 100% in these 3.0's, neglecting the cooling systems directly leads to head failure. so that's what im trying to avoid. however, I change my oil every 1,000 miles. don't ask why, im a maintenance **** and my truck get pampered. the needle is usually a little above that, and there is no creamy gunk on the oil cap that indicates moisture. so I know my motor is not collecting dew inside. as for the oil deposits I have seen none. my logic in this was less heat, less breakdown in the oil, so it should lube better and keep its viscosity. I run the motorcraft 5w20, so its not getting wiped away by the piston, and it runs the recommended psi/ as well as 12-15 psi at idle. as long as im not hurting anything id like to keep my 180 tstat, unless it is going to hurt the motor, then ill switch back.

 

id also like to add that along with the new rad, and tstat, I have a new water pump as well so maybe this is the effect of just having an all new cooling system? the needle does move up and down as I drive as coolant is flushed out at the 180 point and new cooler coolant is coming in. it does even out the longer I drive.

 

Yes, t-stat opening and closing during warm up can be seen on some gauges, depends on where sender is located.

Warm Oil viscosity is measured at 210degF, so SAE 30 is viscosity 30 at 210degF

5w-20 "behaves" like a viscosity 5 oil below 32degF, so isn't as "thick" at lower temps like an SAE 20 would be, and it behaves like a SAE 20 above 32degF, so it is thicker at lower temps, then reaches viscosity 20 at 210degF.
W = Winter by the way, 5w-20 = winter oil

 

keep your 2.9 cool
electric fan
if it's an auto make sure it has a tranny cooler as the lines also run to the rad,i also have a fan on my tranny cooler aAAAaand an engine oil cooler with thermos controlled fan mounted in front of rear tire under the box
always run castrol 0-30 made in germany it's real synthetic not vague north american synthetic
made in germany in small red letters ,see bob the oil guys website

 

As it's been written up before, keep the stock thermostat. The 3.0 is designed around it's operating temps, and the emissions are reduced with the engin running at these temps. Your oil will last longer too, as the warmer engine temps will keep the water condinsation out of the oil.

Second guessing the Ford engineers in this topic is not required. They got it right. If you want your engine to run cool, simply continue with the stock thermostat, and make sure the rest of the cooling system is in peak condition.