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Discussion Starter · #1 ·
Recently our Escape started pushing coolant out of the reservoir every time it was driven. Had it checked for a head gasket leak, none found. Parts that have been replaced, last year it got a new radiator and cooling fans, in the last two weeks the thermostat, coolant sensor and water pump were all replaced. When driving it the temp gauge still goes to HOT.
I've run out of ideas on what could be causing this. Any help would be greatly appreciated.
 

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What does it do in city traffic compared to driving on the freeway? An old rule of thumb was overheating in the city was caused by the coolant pump, and overheating on the highway was caused by a clogged radiator. Vague, but indicative.
The fans are not really needed when traveling above ~30mph, and actually may be turned off(I haven' gotten out to look...).
Have you checked that it is actually overheating? Have you checked the pressure relief cap on the degas bottle(plastic semi-transparent, about half-full of coolant, passenger side)? If the cap relieves at too low a pressure, you will have overflow occur as the coolant expands.
Have you checked the temperature reported to the ECM? I believe there is a CHT -cylinder head temperature - sensor that has its reading available to a OBD-II scan tool. It could be the gauge is also a bit over-reporting. You could also use a non-contact thermometer to determine actual coolant / hose temperature on the hose that routes coolant into the radiator. It should be near 185-190F. If over that number, and the fans are going, or you just came back from a highway run, something else is amiss. The coolant should heat to that temperature(thermostat open) and the allow flow through the radiator. Over that, and either the thermostat is not working properly or there is blockage or other problems.

What brand thermostat did you use?

tom
 

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Discussion Starter · #3 ·
Thermostat was a Murry brand. 5 mile trip ( to town and back) some highway miles the car acts fine. Longer trip with all highway miles is when we notice it runs HOT. Thing is the Temp Gauge will run normal for a period of time then start to fluctuate, move to H for a while and fall back to normal.
 

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Mileage?

The fans are not really needed when traveling above ~30mph, and actually may be turned off(I haven' gotten out to look...).
On my '10 V6, the PCM commands mine off around 35 MPH, give or take a bit.

Tom gave some good things to check, start there.

Had it checked for a head gasket leak, none found.
How was it checked? Was the coolant chemically checked for the presence of exhaust gasses or was it a pressure test?
 

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Fluctuating temp puts my interest in the thermostat and possibly the fans. The stat because they will cause temperature to fluctuate if they are acting up. I would have installed a Stant, Robertshaw, or OEM. I will not install a thermostat from "Bob's Pizza and Auto Parts, Inc." Experience seems to indicate if it is a low-budget no-name it will remain a low-budget no-name because of performance problems down the road.
Mostly the fans do nothing when you are traveling at speed(above 30-35 do not know exact speed). If you get overheating as speed, I point to the radiator as the pump will be running at engine speed(if the belt works) and the radiator is being flushed every minute with a new slug of cooler air, going over the finnage at 30+ mph. That's a good breeze...
If you had air bubbles or voids, generally they will work their way out in a series of heat cycles, unless there is a bleed plug that must be opened until coolant flows out(design precludes natural expulsion of trapped air). I do not know of a bleed screw in these, so expect they will over time self-bleed. Air.
tom
 

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Is this a 4 or 6 cylinder engine?

I can almost guess it's the high fan relay, I'll look around to find some answers...
Since it happens at highways speed, I can guarantee you that it's not the cooling fans or the relays since, as already noted, the fans are turned off above a certain temperature unless the PCM detects an abnormally high CHT reading.

Have you connected a scan tool or equivalent and monitored the OBDII ECT PID and/or the CHT value? Without hard data, you're left with guessing and that doesn't seem to be working very well so far.
 

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2012 Ford Escape 3.0 V6 XLT
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Is this a 4 or 6 cylinder engine?

Since it happens at highways speed, I can guarantee you that it's not the cooling fans or the relays since, as already noted, the fans are turned off above a certain temperature unless the PCM detects an abnormally high CHT reading.

Have you connected a scan tool or equivalent and monitored the OBDII ECT PID and/or the CHT value? Without hard data, you're left with guessing and that doesn't seem to be working very well so far.
I don't think PCM will detect high CHT ...just don't think so..I'm changing my mind and going with messed up thermostat...
 

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Discussion Starter · #10 ·
Update, just got a video from my wife, she driving the Escape and the Temp Gauge is fluctuating from normal to H back to normal. Thermostat was replaced about two weeks ago. Think is worth changing again?
 

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Update, just got a video from my wife, she driving the Escape and the Temp Gauge is fluctuating from normal to H back to normal. Thermostat was replaced about two weeks ago. Think is worth changing again?

It almost acts like that thermo couple is acting intermittent on the thermostat...I'd change it out try one more time..
 

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Thermostat was replaced about two weeks ago. Think is worth changing again?
Well, they're cheap and easy, but if the E was acting exactly the same way with the original stat, I think it's a low percentage shot.

If it's pushing coolant, it's definitely getting hot so I don't think you have an instrumentation issue.

If it never overheats around town but consistently does so on the highway, I'd load a radiator into the parts cannon to eliminate that.

John
 

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I don't think PCM will detect high CHT
Of course it will detect a CHT that is out of operating range. Go look at the P128x DTC definitions.

As I noted previously:
Have you connected a scan tool or equivalent and monitored the OBDII ECT PID and/or the CHT value? Without hard data, you're left with guessing and that doesn't seem to be working very well so far.
Oh well, just keep on guessing if you don't want to do any actual diagnosing. Good luck.
 

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Discussion Starter · #14 ·
As I noted previously:
Oh well, just keep on guessing if you don't want to do any actual diagnosing. Good luck.
[/QUOTE]
Actually I will start diagnosing the Escape when I have it in front of me. Hard to scan a vehicle when it' s sitting 30 minutes away and still at my regular job for another 2 hrs.
 

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Discussion Starter · #15 ·
After driving for a while,ECT live data on temp fluctuates between 208 and 239 degrees. 185 to 220 it stays in the normal range, after that it climbs to 239 and immediately falls back to 210-225 and then starts to climb again.
At idle after driving the fans are on and the temp climbed to 243.
 

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Have you taken a look at the serpentine belt to see if it is worn? Have you looked at the belt tensioner? I think they will indicate when a belt is out of normal range by a pointer line on the tensioner that goes past a spot that shows normal range. Either way, if the belt slips, such as when the A/C clutch engages, or the alternator gets more load(fans turn on? A/C clutch? blower motor? headlights?)...
I still would point to the thermostat. or whatever it is that controls coolant flow. I am ignorant if the EMT 3.0 has electronic coolant flow control of any sort, but did not think it did.
Did you gain access to a non-contract thermometer to point at the thermostat housing, and the upper/return radiator hose? If so, do the numbers come close the the OBD-II readings reported to the scan tool?
tom
 
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