Water temp and MPG

[Jim_WY]

Here is what I see everyday. I have good amount of heat though. My coolant temp is 175 and the thermostat is new but don’t know what temp. It is going to be 0 tonight.

My temp gauge wasn't reading as high as it always used to (it always used to read up in the very middle of its range), so I put in a new thermostat (198°) and now my gauge reads even lower than it was before I put the new thermostat in!

Now, after the engine has had plenty of time to warm up, it still only reads just like what is shown in your photo.

As with you, I get plenty of good heat from the heater (it's been around freezing plus or minus 20 degrees or so) for the last week. But that's no assurance that the engine is truly getting up to the correct operating temperature.

Do I need to buy some kind of code reader so I can see what the ECU is reading from the other sensor?

This is a bit strange.

 

[PAExplorerXLT]

Exactly why I finally just bit the bullet and ordered a smoke pro. I CAN'T WAIT to finally have a evap smoke machine lol.

Is it easy to tell where smoke is coming from? I can easily see a situation where you may not be able to.

 

[Turdle]

Do I need to buy some kind of code reader so I can see what the ECU is reading from the other sensor?
.

What I have is a scangauge 2. It can read data from several sensors, and, also read and clear the check engine codes.

It will display 4 "gauges" at a time. I have mine set to read trans temp, coolant temp, air intake temp and true volts, but you can switch them around at any time by the push of a button. I have mine mounted between the hvac controls and info center ( cubbyhole) area of the center console. Very cool device!

http://www.scangauge.com/

 

[ZWilson07]

Is it easy to tell where smoke is coming from? I can easily see a situation where you may not be able to.

"Generally" yes it usually can be seen pretty easily especially with the engine being off/cold so you can really get in there and working inside of a garage. They also do make smoke with dye that can help but I have never felt the actual need to go buy it, although I am sure it has its place for certain shops. Obviously working outside in a windy environment, not having a good light source, specific location of said leak, and the engine configuration all play a major role in this. Especially the particular motor configuration and the room around things within the engine bay.

I am sure in a particular case where person A) spent $1000 bucks in hopes to fix an issue and couldn't really tell where the leak was coming from, might feel like it was a lot of hype and way overpriced. Person B) maybe could have been struggling with an issue for a long time and decided to finally bite the bullet in which it ended up solving their issues. They end up falling back in love with the vehicle and actually enjoy their daily commute instead of dreading it with that particular vehicle. All of the sudden it becomes the best $1000 bucks they have ever spent. So I am sure like many things in life, it is all relative.

This is really one of the last major diagnostic tools I need that I actually will own, so I can't wait. Aside from that, without a evap smoke machine, it is about impossible to truly find/diagnose/fix with certainty, exhaust and vacuum leaks. Yes you can use propane while listening, monitoring fuel trims, O2 sensor readings, use a cigar/cig, etc but nothing beats having a true smoke machine if you work on a lot of vehicles and/or are struggling with lean conditions or drivability issues from leaks. It's one of those tools that while expensive, once you have one, you will wonder how you ever went without it you know.





OP: to put it in perspective, on my way home from work tonight, -5 to -10 F temp with -15 windchill, I was still seeing around 200-205 F or so from my coolant. So I would definitely say something might be up or starting to develop.

 

[koda2000]

My temp gauge wasn't reading as high as it always used to (it always used to read up in the very middle of its range), so I put in a new thermostat (198°) and now my gauge reads even lower than it was before I put the new thermostat in!

Now, after the engine has had plenty of time to warm up, it still only reads just like what is shown in your photo.

As with you, I get plenty of good heat from the heater (it's been around freezing plus or minus 20 degrees or so) for the last week. But that's no assurance that the engine is truly getting up to the correct operating temperature.

Do I need to buy some kind of code reader so I can see what the ECU is reading from the other sensor?

This is a bit strange.

Could be you just got a defective thermostat. It happens more often than you think. You need to determine what your actual coolant temp is. You can do this with any number of devices (including a meat thermometer). If your check engine light is on, you may have a code P0125 (insufficient temp to enter closed loop mode) which will really lower your MPG (I've seen 8 MPG less with this code). As your temp gauge is registering something, you will get heat (mine wasn't registering at all and I still had some decent heat). Your temp gauge will not register anything until the coolant temp reaches 167F as I recall. When your coolant temp is in the "NORMAL" operating range the needle should be in about the center of the gauge.

Dumb question, but are you sure your thermostat was installed facing the right way? The pointy end always faces away from the engine.

 

[PAExplorerXLT]

Could be you just got a defective thermostat. It happens more often than you think. You need to determine what your actual coolant temp is.

The keyword is “actual”. The 175 degrees I am reading is what my iPhone app shows after consulting with the OBDII WiFI dongle which in turn is getting its information from some sensor in the engine. None of there are direct readings. As for the thermometer, where do you put it? Expansion tank? But the coolant might have cooled some by the time it gets there.

 

[koda2000]

The keyword is “actual”. The 175 degrees I am reading is what my iPhone app shows after consulting with the OBDII WiFI dongle which in turn is getting its information from some sensor in the engine. None of there are direct readings. As for the thermometer, where do you put it? Expansion tank? But the coolant might have cooled some by the time it gets there.

If you want to use a thermometer, remove the rad cap when the engine is cold. Stick the thermometer in the radiator and run the engine up to normal op temp. As water boils at 212 degrees F (at sea level) and your coolant temp will not reach much above 190-195F, under normal circumstances, the radiator will not boil over during the test. You may lose a little coolant due to circulation, but hardly any. My VOM has a temperature probe, which I can hold on the metal thermostat housing (or in the radiator) to get an actual accurate reading. Keep in mind that ambient temp can have some effect on how hot your coolant gets.

 

[DJRockit69]

Now is Ur explorer a 5.0 cause I'm having the same problem. I'm not throwing any codes either I have a aftermarket temp gauge in front of my T STAT and what happens to me is the the gauge in the dash will reach the mid point level and when the thermostat opens it plummets to the same point where Ur at and stays there while my temp in the radiator it between 170 to about 180. it's weird cause my gas mileage goes way down after the thermostat opens. I've had this issue for a while and I haven't come close to solving it my next step is to replace the temp sensor in the engine then possibly a coolant flush I was maybe thinking an air bubble is in the system.

 

[koda2000]

Now is Ur explorer a 5.0 cause I'm having the same problem. I'm not throwing any codes either I have a aftermarket temp gauge in front of my T STAT and what happens to me is the the gauge in the dash will reach the mid point level and when the thermostat opens it plummets to the same point where Ur at and stays there while my temp in the radiator it between 170 to about 180. it's weird cause my gas mileage goes way down after the thermostat opens. I've had this issue for a while and I haven't come close to solving it my next step is to replace the temp sensor in the engine then possibly a coolant flush I was maybe thinking an air bubble is in the system.

Mine was a 2000 5.0L AWD Mountaineer. Replacing my thermostat fixed my problem immediately. My water temp was a bit colder than yours (as my gauge wouldn't even move off of "C" unless I left it idling for 15-20 min's. Then it threw the P0125 code). Like I said, I believe 167F is the point at which the gauge begins to move. Once the gauge indicated normal temp, the fuel economy picked right up to pretty much match my other 5.0's (AWD's are heavier so it tends to get about 1 mpg less then my 2wd's). I don't think you have air in your system. The V8's bleed out the air easily.

 

[2000StreetRod]

measuring engine coolant temperature

In my opinion measuring the radiator temperature does not determine the engine coolant temperature (ECT). In the summer using a remote reading thermometer the radiator temperature was 150 degrees F when the engine coolant temperature was 190 degrees according to the ECT sensor via the OBD-II bus. Even measuring the temperature of the thermostat housing or the water pump may not be an accurate ECT value because of airflow from the radiator fan. I think the ECT sensor provides the most accurate reading either via the OBD-II bus or the resistance across the sensor.

If the antifreeze protection is minimal for the ambient temperature the engine coolant may partially freeze resulting is a stuck open thermostat but that seems unlikely. "Fail safe" thermostats stay open after being overheated. Marginal antifreeze protection often results in a frozen radiator which causes overheating. I recommend installing a new high quality, non-fail safe thermostat. I suspect your existing thermostat is stuck open.

 

[DJRockit69]

So I'm having a hard time finding a non fail safe thermostat

 

[Alaskakid87]

Here is what I see everyday. I have good amount of heat though. My coolant temp is 175 and the thermostat is new but don’t know what temp. It is going to be 0 tonight.

I am having this similar issue with my explorer as well. Not even 3 weeks ago we replaced my water pump, upper hose, T-stat, and belt and since I have yet to be run out of my explorer because it got too hot....

A few friends of mine and my dad who's a mechanic said my heater core maybe plugged with debris he is going to try and blow it out and hopefully get my heat and airflow back, not even 500 miles ago I replaced the blower motor and resistor so I am stumped and my heat gauge is running like in the pic above...

 

[DJRockit69]

I'm going to replace my thermostat this weekend and if that doesn't fix it I will move on to the heater core

 

[koda2000]

I'm going to replace my thermostat this weekend and if that doesn't fix it I will move on to the heater core

your heater core (huge job to replace by the way) has no effect on your engine temp. if your engine isn't getting hot enough to put the temp needle in the center of the gauge and give you heat, there' a 99.9% chance the problem is your thermostat. make sure the new one you purchase is stamped between 190-195 degrees F. I believe OE was 192F, don't just go by what's printed on the box.

 

[DJRockit69]

I have a 192 sitting at home right now

 

[DJRockit69]

And I do have good heat that's the odd part of this I already replaced the temp sensor that's goes in the engine block

 

[koda2000]

And I do have good heat that's the odd part of this I already replaced the temp sensor that's goes in the engine block

As I said earlier, I thought I had good heat when my gauge was setting on COLD. Now I have great heat.

 

[Flash]

Now I have great heat.

I'll never need great heat. I want great A/C.

I was driving my XLT around in what tourism companies call the Alpine region here, I was too hot with just what was leaking past the blend door.

 

[PAExplorerXLT]

I'm going to replace my thermostat this weekend and if that doesn't fix it I will move on to the heater core

What’s the connection? This is like if you are car doesn’t move, you change your tires.

 

[koda2000]

What’s the connection? This is like if you are car doesn’t move, you change your tires.

if you don't understand the connection between your engine's thermostat, coolant temp and heat, I don't think we can explain it to you.