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Engine overheats when Idling

efBrianM

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95 Ex Exp, 01 Ex Sport
We have a 2001 EX with 4.0L SOHC engine, auto, 4X4, with 188,000 miles on it. This summer it started overheating when idling or in stop and go traffic, even without the A/C on. This has never been a problem before. The temperature is just fine going down the highway.
I thought this was a classic situation of a fan clutch not working, and it still had the original clutch in it, so I replaced it. I put in a Severe Duty. No change in symptoms.
I have not replaced the radiator as it was replaced in Jan. of 2018. I do most of my own repairs, unless the weather is bad, or other things demand my attention, so I had the radiator replaced. I have no idea whether the original rad was a single or a 2 row core. The one the shop put in is a single row. Some here are of the opinion that a single row was what Ford installed in a 2001 most of the time.
Last February, in north east Kansas, we had a really cold week and wouldn't you know it, the plastic thermostat housing (2nd one) started leaking. So I had the same shop replace it with a metal one. I believe they changed the thermostat. I replaced that one. No change in symptoms! By the way, the thermostat has a spring loaded plate on the bottom of it. What does this do? Looks like a check valve.
The engine still had the original water pump. I have a hard time believing metal impellers go bad, but seals and bearings do, and I did have a slow coolant leak. So I replaced the pump. The rotation was listed as REV, I assume that means CCW. Still overheats when idling!
During all this time, I had the radiator out twice. The first time I took an air hose to the fins. The second time out I took the garden hose to it. Laid it down flat where I could see underneath it, applied the water to the top side (not much pressure). Water runs easily thru it. Still overheating!
I checked the radiator cap and found the seal torn, replaced it. No change in symptoms!
I know the condenser is not clogged up with bugs, leaves, etc as I also did some A/C work and the condenser was replaced.
The fan shroud is on and in good shape. The baffle that goes underneath and bolts to the frame is in place. There's rubber baffles between the radiator and the condenser, and even some out in front of the condenser.
I thought I could for sure fix on overheating problem, but I'm out of ideas!

I was going to post this yesterday, but thought I should have it scanned. We've been running with a CEL for some time now, a code associated with the evaporative emissions (purge/vent). Well, no code for that, but it did have a P0171 and a P0174, system too lean, bank 1 and 2 I believe. Could this be related? Do engines that are running lean, run hotter? It does have a bit of a rough idle.

Brian
 


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C420sailor

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Define overheating. Does it actually boil over, or does the gauge just run up into the red?
 




donalds

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Are you losing coolant
In a sense of not leaking but still disappearing
 




fast_dave

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Last February, in north east Kansas, we had a really cold week and wouldn't you know it, the plastic thermostat housing (2nd one) started leaking. So I had the same shop replace it with a metal one. I believe they changed the thermostat. I replaced that one.

Please clarify.

In other words - for sure - is your current thermostat NEW or ?

Just sayin ' - a swap out requires loosing (3) 10mm bolts and spending $7 for a new Stant thermostat to positively establish a baseline and eliminate the thermostat as the issue ;)
 




efBrianM

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Define overheating. Does it actually boil over, or does the gauge just run up into the red?
No, never boiled over and never into the red. I've never let it get out of the "quarter circle" area. close to the end of that quarter circle tho.

Are you losing coolant
In a sense of not leaking but still disappearing
Once I got all of the air out of the system, the radiator has been brim full! I've driven it about 700 miles since then.
I never took it more than 30 miles from home!
 




efBrianM

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Please clarify.

In other words - for sure - is your current thermostat NEW or ?

Just sayin ' - a swap out requires loosing (3) 10mm bolts and spending $7 for a new Stant thermostat to positively establish a baseline and eliminate the thermostat as the issue ;)

Yes, brand new from local O'Reilly's. I can't find the receipt at the moment to verify the brand.
 




donalds

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I'd start with a full flush
And a nice quality T stat
 




KeenKilo

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If it’s not going red I think thermostat. The spring reacts to heat allowing coolant to flow past that plate when it gets hot.

Different thermostats have different temperature threshold, check which is factory and check what you’ve got.

Fluid flush is good idea. lean code could cause coolant loss but that’s the only way, that I know of, it would cause overheat.
 




fast_dave

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Once I got all of the air out of the system, the radiator has been brim full! I've driven it about 700 miles since then.

Just sayin'

Monitor the coolant level by leaving the radiator capped, and watch the level in the Coolant Overflow Tank.

Once the system burped out all the air, has the level in the coolant overflow tank held steady OR have you had to add coolant?
 




efBrianM

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Yes, once the air got out, the overflow tank held steady.
 




efBrianM

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If it’s not going red I think thermostat. The spring reacts to heat allowing coolant to flow past that plate when it gets hot.

Different thermostats have different temperature threshold, check which is factory and check what you’ve got.

Fluid flush is good idea. lean code could cause coolant loss but that’s the only way, that I know of, it would cause overheat.

T gauge does not go into the red because I don't let it. I plan my route so there's very little stop and go traffic, almost all cruising speed.
If I have errands to run with a lot of stops in the city, I drive the other one.
No more letting it sit and idle with the A/C on when I'm eating a lunch at say, Sonic or McDonalds.
The T stat I took out was stamped 198 deg F. I put in a 192, thinking that's what it's suppose to have.
The coolant looks pretty good, but I have never flushed it.

For what it's worth we bought it from a dealer with 57,000 miles on it (188,000 now). They installed new intake gaskets before we brought it home.
Intake gaskets have not been changed since.
 




Josh P

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The orientation of the fan blades correct? how many blades are on the fan?
 




KeenKilo

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I know These questions are annoying but we do not know. No stone left unturned
 




efBrianM

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The orientation of the fan blades correct? how many blades are on the fan?

There are 11 blades. Standing in front of the grille, looking at the engine, the fan blades turn CCW.
Turning CCW, the orientation of the fan blades are such that they pull air 'into' the engine compartment.
 




efBrianM

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Marauder 1

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Hello: Ok the first question might seem dumb but have you checked the hoses to make sure they are not collapsing at idle? I've seen this on a buddies truck the bottom hose would semi collapse and restrict water flow. Is there any discoloration to the motor oil? do you see a film on the coolant when you open the cap on the radiator? also have you noticed more water from one side of the exhaust than the other at idle? I know you said you don't let it overheat but how long can it idle before said gauge starts going up?
 




efBrianM

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Apologize for the delay. I saw your post on my smart phone earlier, but all the pop-up ads make it difficult to reply. No pop-ups on the desktop.
have you checked the hoses to make sure they are not collapsing at idle? The hoses are ok - none collapsing.
Is there any discoloration to the motor oil? Just looking at the dipstick, no.
do you see a film on the coolant when you open the cap on the radiator? no, and not in the overflow tank either.
have you noticed more water from one side of the exhaust than the other at idle? It just has a single exhaust. Once its warmed up, I see
no humidity coming out of the exhaust. I can check the exhaust in the morning when it starts up cold and warms up.
you said you don't let it overheat but how long can it idle before said gauge starts going up? So, today I had to use it to haul domestic
water (water tank in a trailer), 12 miles one way an no stop and go. I did not run the A/C either way. When I got home, I let it idle and made some notes.
The normal resting place for the temp gauge pointer is right over the bottom of the thermometer symbol on the temp gauge faceplate.
It took approx. 6 minutes to detect the pointer moving upward, After 20 minutes it never did get out of the "normal" zone, but close to the high end. Engine RPM was about 1200 - 1300. Again, the A/C was not turned on. Had I turned on the A/C, pretty sure the temp would have gotten into the red. Per our weather station for the house (it has an outdoor temp sensor), it was about 83 deg. F when I was doing this.

Too wordy I know. Brian
 




Marauder 1

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"Engine RPM was about 1200 - 1300. Again, the A/C was not turned on." is that in park? Idle seems a bit high, I think your idle should be between 600 and 800 at idle in park. Even if that is in gear that's to high with the A/C off. Sounds like a TPS issue or I'm trying to remember if there is an idle adjustment screw on the throttle body. I'll have to go look tomorrow on my sons,
Seeya
Mark
 




Indispensable Explorer

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"Engine RPM was about 1200 - 1300. Again, the A/C was not turned on." is that in park? Idle seems a bit high, I think your idle should be between 600 and 800 at idle in park.
Seeya
Mark
Could just be a normal function of the engine. A few years ago when I nearly overheated in traffic, I had the same RPM that Brian is experiencing. It seems that the engine idles faster when it is hot and in park or neutral.
 


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efBrianM

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If the engine is at its normal temp, it does idle at about 700. I have noticed that as the temp goes up so goes the RPM.

As I re-read my text, I see that could have worded that different, sorry 'bout that!
 




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