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Engine overheats on highway?

Tiny
MATTSPONY
  • MEMBER
  • 2002 FORD RANGER
  • 2.3L
  • 4 CYL
  • 2WD
  • MANUAL
  • 150,000 MILES
Hey everybody. Hope you can help me out. Had a thermostat go out about a month ago. No heat and no reading on temperature gauge. Replaced that and got my heat back but now.

Truck runs fine at idle. Normal gauge position. Piston software shows steady 260 degree CHT. When I take it out on the highway the CHT will steadily rise until about 290. The temperature gauge jumps to the red. When I pull over and check. There's no boiling. Top hose is really hot but I can still touch. After restart the gauge is in normal range again with the ECT back around 260. It repeats the cycle after a few miles.

Mechanic I checked with said radiator but also checked for a head gasket. His test turned out negative though.

I changed the radiator and bleed the system but the problem remains.

Notes: It did this twice before about 6 months before the thermostat was replaced but I was pulling a huge hill and figured that was why. Never thought about it again until it started doing it all the time.
Aftermarket radiator had a filler neck. So I have both a 16lb radiator cap and a 16lb expansion tank cap now.
No coolant loss has been noticed.
Check engine light does throw a code for ECT circuit.

Any ideas are greatly appreciated. Thanks
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Sunday, January 26th, 2020 AT 2:29 PM

40 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,923 POSTS
I had this happen about five years after installing an aftermarket thermostat in my car. The solution was to remove the thermostat and drill a 1/16" hole in the center plate, then reinstall it that way.

This guide can help as as well.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

The coolant temperature sensor sits some distance away from the thermostat. As the coolant gets hot, the rising temperature is seen by the temperature sensor first, but it hasn't made its way to the thermostat yet. By the time the thermostat gets hot enough to open,, the gauge is already reading too high. Upon opening, cold coolant from the radiator rushes into the engine and causes the gauge reading to go back down. At that point the thermostat closes again. This cycle repeated four to six times on my van within about the first seven or eight miles, then it smoothed out.

The pin hole, which you will usually find on OEM import thermostats, lets the hot coolant sneak over to the thermostat quicker, so it opens up sooner.
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Sunday, January 26th, 2020 AT 3:08 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening,

Can you verify those temperatures? 260 and 290 are way too hot. They should be around 195-200 degrees.

If it is running that hot, good chance there is head gasket damage. You need to have a leak down test done to confirm.

https://www.2carpros.com/articles/head-gasket-blown-test

Roy
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Sunday, January 26th, 2020 AT 3:14 PM
Tiny
MATTSPONY
  • MEMBER
  • 3 POSTS
The 260 is the cylinder head temperature. I've been told that it's always higher than actual coolant temperature. Unfortunately I've been unable to find a coolant temperature reading on the several apps I've tried. Not sure if the PCM broadcasts it or not.
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Sunday, January 26th, 2020 AT 3:31 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Head gaskets are rated at 245. If you run 260, they are damaged. That number is set by the gasket manufacturers.

Roy
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Sunday, January 26th, 2020 AT 3:35 PM
Tiny
MATTSPONY
  • MEMBER
  • 3 POSTS
Thank Roy for that depressing news, lol. I'll get a leak down test in the next day or two to confirm.
I'm guessing its possible even though it passed the chemical test with no other symptoms. Still runs good when it's not overheating. No oil in water and vice versa. Nothing out the back end and no coolant loss.
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Sunday, January 26th, 2020 AT 3:47 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
The chemical test is not always accurate. I have been fooled by that test too many times.

Coolant in the oil is when it is really bad.

Do the test to be sure.

You are welcome.

Roy
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Sunday, January 26th, 2020 AT 3:49 PM
Tiny
GRAHAM BUTLER
  • MEMBER
  • 2 POSTS
  • 2002 FORD RANGER
Engine Cooling problem
2002 Ford Ranger 4 cyl Four Wheel Drive Manual

engine intermittantly overheating. Thermostat changed to no avail. Not losing any water so am assuming head gaskett is ok. Any assistance / ideas please?
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Wednesday, October 28th, 2020 AT 2:05 PM (Merged)
Tiny
KEVIN12881
  • MEMBER
  • 336 POSTS
By itermidiat do you mean just a bit over normal? Over 200? Could be, fans, clogged radiator (both inside or out) not holding pressure, drive belt malfunction. Does it get hotter at a stop, or are there any other patters. Water pump could be going. Or bad temp guage
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Wednesday, October 28th, 2020 AT 2:05 PM (Merged)
Tiny
GRAHAM BUTLER
  • MEMBER
  • 2 POSTS
After an hour or so driving (town & motorway) indicator goes to the "red". Leave for 20 mins, temp returns to "normal" then continue driving again. Another hour or so, temp raises again. Thermostat has been changed, am going to get the rad checked out next week.
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Wednesday, October 28th, 2020 AT 2:05 PM (Merged)
Tiny
KEVIN12881
  • MEMBER
  • 336 POSTS
So you are saying that while at high speed (60-70) the truck overheats. Then while driving 40-50 the temp will come back down? Is that correct? How hard is you engine having to work to go 65? Does your engine stay at or above 3k the whole time while at highway speed? Donate for a pro to help, even a few bucks will work
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Wednesday, October 28th, 2020 AT 2:05 PM (Merged)
Tiny
JLS5085
  • MEMBER
  • 2 POSTS
  • 2002 FORD RANGER
Engine Cooling problem
2002 Ford Ranger 4 cyl Two Wheel Drive Automatic

The truck has been in the dealership's garage three times and they have been unable to fix the problem. After the engine warms up, the temp guage will spike up. Then I can get it back down by turning on the heater. No heat comes out of the heater. But the temp goes back down within a min. If I don't emidiatly turn off the heater, the spike returns and I have to turn off the truck to get the temp down. The shop said the core is fine, and they are baffled. They of course they still billed me. This problem has already cost over $700. Has anyone had this weird problem?
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Wednesday, October 28th, 2020 AT 2:05 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
This is kind of weird-Did they check the thermostat could also be air lock in the system

The thermostat controls the engine temperature
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Wednesday, October 28th, 2020 AT 2:05 PM (Merged)
Tiny
JLS5085
  • MEMBER
  • 2 POSTS
Thermostat has been replaced. If the motor is vacume locked, how would I fix that? Pull the gooseneck and fill the block?
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Wednesday, October 28th, 2020 AT 2:05 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Generic bleeding


https://www.2carpros.com/forum/automotive_pictures/12900_bleeding_cooling_system_3.jpg

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Wednesday, October 28th, 2020 AT 2:05 PM (Merged)
Tiny
GTPERSER
  • MEMBER
  • 2 POSTS
  • 2002 FORD RANGER
  • 4 CYL
  • 2WD
  • MANUAL
  • 108,000 MILES
Have just replaced plugs and coil, after finding number three cylinder misfiring. Checked compression on all cylinders and they are within specs.
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Wednesday, October 28th, 2020 AT 2:06 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
For a start cheap fix-find the thermostat and replace it and see what happens then comeback-
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Wednesday, October 28th, 2020 AT 2:06 PM (Merged)
Tiny
GTPERSER
  • MEMBER
  • 2 POSTS
Replaced the thermostat, cost $142.00 for thermostat, only from Ford Dealer. Dont know if this is the cure yet, The fan clutch is very suspect, but the thermostat housing was cracked internally. The housing is plastic.
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Wednesday, October 28th, 2020 AT 2:06 PM (Merged)
Tiny
LAGANDY
  • MEMBER
  • 1 POST
  • 2001 FORD RANGER
  • 220,000 MILES
Engine overheat after about fifteen minutes. Engine get loses power and shuts off.
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Wednesday, October 28th, 2020 AT 2:06 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening.

Is the coolant level low?

Did the car smoke at all?

Does it crank normally?

I am concerned about a possible blown head gasket.

It sounds like the thermostat may have stuck closed causing it to run hot and a result could be the head gasket failing.

Roy

https://www.2carpros.com/articles/symptoms-of-an-overheating-engine

https://www.2carpros.com/articles/replace-thermostat
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Wednesday, October 28th, 2020 AT 2:06 PM (Merged)
Tiny
ZACMAN44
  • MEMBER
  • 2 POSTS
  • 2000 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 176,000 MILES
Returning from trip - after about 200 miles the engine started to heat up. Before that all fine and had AC on. I pulled over and put the heater on full blast to draw heat. Instead of heat coming in to the car the air was still cold as if the AC was on. So-I could not run the heater to pull heat off engine - seemed to be doing the opposite. Then smoke smell from heater-AC vents so turned car off and then lots of smoke/steam from under hood. Had it towed to a nearby repair shop. I told them it might be a thermostat as getting cold air when heater on was odd. There was a clicking sound - periodic - before the problem appeared. Thus, I thought maybe a water pump. Shop called and I am being told there was a big leak in radiator which needs to be replaced ($660) and they will then check on the block and other things that could also be wrong.
I am OK with that as I have a lot of miles on it, but it sounds odd where the problem was not gradual - and also concerned because they told me oil also needed changing because it was very dirty but I had just changed it two weeks before. I guess that triggered a degree of distrust but who knows. Any ideas? Thanks. - Oh, also had the fan clutch assembly replaced about two months ago.
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Wednesday, October 28th, 2020 AT 2:06 PM (Merged)

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