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2003 2.3L getting too hot??


Soledad

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Ok, this thing is driving me absolutely nuts. It's a 2003 XL 2.3L 2wd 5spd manual trans. Truck is all stock.

I bought this truck about a month or so ago. On it's first maiden voyage coming back from the dump the degas bottle sprung a leak and the radiator end cap blew a seal. I also found out the cooling system had the wrong coolant in it (green stuff). So, I replaced the degas bottle and cap with new Motorcraft parts. Napa didn't have a manual trans radiator so I went with the auto trans radiator. I flushed out the system with a garden hose (didn't use any cleaning stuff though) for about 10 minutes and then flushed with 6-7 gallons of distilled water then through in Zerex G-05 (Ford Gold equivalent). Then put the new parts in. Once I got all that done I called it good.

Next trip out I start monitoring the coolant temps with FORScan. I notice ECT is running 228* and CHT is running 245* pretty solidly. I start smelling coolant and get it home. Come to find out, someone had an issue with the plastic "T" just above the starter and cut it out of the overflow hose and put in their own. One of the screw clamps had loosened up so I tightened it and that solved that leak.

So now I start going over everything. I feel the bottom radiator hose and it's cold, but the top radiator hose is hot. Thinking I have a stuck thermostat I order up all new parts (new Motorcraft thermostat, new Hitachi water pump, new Hayden fan clutch and new radiator hoses) because the truck has 130,000+ miles on it. I replace all of those, burp it and take it out for another spin. This time though, FORScan is saying the ECT is 228*-240* and CHT is 250-275* and the bottom radiator hose is STILL cold. The idiot gauge in the dash runs anywhere from the high side of the middle to 3/4 of the way to hot. Thinking I may still have air in the system, I burp the cooling system according to the Ford procedure. It made no difference.

And what's odd is that when the truck is cold it has normal power. But, after a 30 mile trip the truck has lost a lot of power. It won't even hold 45 mph in 3rd gear on a small hill.

The oil is clean and not milky, there is no oil in the coolant and there is no white smoke from the exhaust. It's also not puking coolant. But, I've ordered up a cooling system pressure tester kit which should be here next week just to make absolutely sure the system is sealed tight.

I've even tried running with the A/C at max and the heater at max and neither make any difference in the coolant temps.

At this point I'm dumbfounded. I don't know if these temps are normal and I don't know if a cold bottom radiator hose is normal for these 2001-2003 Duratec engines. A cold bottom radiator hose on any other car would tell me there's a radiator blockage (or on this engine, the thermostat isn't opening).

So a few questions:
1. What temps is everyone seeing for those who actively monitor coolant temps?
2. Is a cool to tepid temp bottom radiator hose normal for these engines?
3. Are these engines known for cooling system blockages, air or crud?

I REALLY don't want to have to drain the system again and pull and test the thermostat. It's a such a pain in the rear.

TLDR; Truck "seems" to be running hot after replacing degas bottle and cap, radiator, fan clutch, water pump, both radiator hoses and thermostat. Top radiator hose is hot and bottom radiator hose is cold. Is that normal? ECT ranges between 228*-240* and CHT ranges between 250*-275*. Are those temps normal? No coolant in the oil. No oil in the coolant. No white cloud from the exhaust. Degas is not puking. Truck loses power the hotter it gets.
 
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RonD

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yes, running way to hot

195-200degF operating temp, 192degF thermostat is stock
Above 1/3 and below 1/2 on gauge

225degF when climbing a long grade, just above 1/2 on gauge

T-stat is opening if upper hose warms up but there is no flow thru rad if lower hose doesn't warm up.
Lower hose averages 10deg cooler than upper, so if upper is 195degF then lower will be 185degF, far from cold.
That applies to all vehicles

How does the heater work?
Set fan on high and feel the warmer air, if air starts to cool even a little you have low flow in the system.
Coolant should be flowing thru the heater core, in any vehicle, fast enough to keep air temp warm/hot

I haven't pulled apart a 2.3l Duratec cooling system before, but some newer systems have a flow direction, reversing 2 hoses can cause less flow thru the whole engine.

CHT should run around 215 to 220degF, slightly warmer than ECT, under load it will go up just like coolant temp

ECT = engine coolant temp
CHT = cylinder head temp

EDIT:
If an engine has thermostat on lower rad hose, Toyota does that, then you use a 180degF thermostat, that is the same as 190degF on upper hose because of the 10deg cooling.
 
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Soledad

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Thanks RonD! And darn it! I guess I knew in the back of my mind there was a problem but just didn't want to acknowledge it because of the amount of work that's going to be involved.

The heater definitely gets hot but I'm not entirely sure how hot. I have a non-contact IR temp gun and both heater hoses read about 200*-210*.

Speaking of the temp gun, here's what I found:

- The top radiator hose reads around 170*-180*
- The bottom radiator hose reads around 83*-90*.
- The thermostat housing reads about the same as the bottom radiator hose.
- The overflow pipe down by the thermostat reads about 180*.
- The degas bottle reads 180*-193*.
- The heater hoses read between 200*-210*
- The steel coolant pipe(s) that connect the top radiator hose to the back of the head read between 210*-243* depending on how far back you take a reading while getting closer to the back of the head.

What I've read about the "electronic" thermostat in these 2001's to 2003's is that it's a 190* AND a 208*. If the heater circuit isn't activated it will start opening at 208* and be fully open by 235*. But, under certain conditions the computer will activate the heater inside the thermostat to melt the wax pellet and open it up early so that it behaves like a 190* thermostat. And if the heater circuit fails then the engine will run hotter than normal.

And so I figure either the "heater" circuit in the PCM isn't functioning and isn't opening the thermostat earlier than 208* OR I have a defective new Motorcraft thermostat OR I have a blockage somewhere in the system.
 
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Tedybear

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Interesting results with the upper hose and bottom hose.... I'd be interested in using the non-contact IR on the radiator. That's quite the temp difference.

S-
 

Soledad

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Yeah, I really want to temp gun the radiator. But, the thing is hidden behind a fan shroud, an electric fan and the A/C condenser so it's completely covered up. :-(


Oh and something else to add, both the ECT and CHT sensors read about 4* above ambient temp after a few days cold soak so I don't think they are bad.
 
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Soledad

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I really wish I could find a flow diagram of exactly how this Duratec cooling system flows and works. I have alldatadiy.com but it's not been very helpful.

I'm going to think out loud here because I need to see if it all makes any sense. If I'm wrong anywhere PLEASE correct me.

- The top radiator hose is between 170*-180* and the bottom radiator hose measures between 83*-90*. This would indicate a blockage because no radiator would cool that well.
- Because the temp difference between the two is so large the blockage would either be A) in the radiator somewhere or B) the thermostat itself.
- IF the thermostat were not opening then there we would be zero flow through the radiator. However, there is a jiggle pin in the thermostat so there should be a tiny amount of flow volume but maybe not enough to heat up the thermostat to 208* to start it opening.
- If the thermostat never see's 208* coolant then it will never open UNLESS the PCM see's a need (engine load, IAT, ECT and CHT) to energize the heater circuit and open it sooner than 208*.
- The reason the engine isn't majorly overheating and hasn't yet hit the PCM's fail-safe cooling strategy is because of several extra cooling system pipes/hoses keeping the coolant flowing albeit at a much slower pace:

1. The overflow hose that runs from the thermostat, behind the engine block to the bottom of the degas bottle. This hose also provides coolant flow to the EGR I believe.
2. The coolant bypass hose that runs from the side of the block near the thermostat to the water outlet connector adapter (which houses the ECT sensor) on the back of the head.
3. And the degas overflow hose that runs from the side of the degas bottle to the metal pipe that has connections for the heater core.

- But, there must be some type of cooling going on because the ECT and CHT temps never climb higher and higher. Acceleration and long hills raise the temps and going down a long hill cools them off. It's not overheating. It's just running hotter than normal.

I'm hoping it's not a blown head gasket or cracked head but I would think there would be oil in the coolant or coolant in the oil or the exhaust would smell sweet. But I have none of that. Would a cooling system pressure test expose a blown head gasket or cracked head?
 
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Tedybear

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Gotta sneak this one in sense I'm at work.

Had a like problem with a P/O that used green and mixed it with the G12 that our VW requires. Made a huge mess that left this white, almost like a paste inside everything.

I'm wondering if the radiator is partly plugged up restricting the flow. It kinda makes some sense...and not at the same time. The upper hose is 'hot', so that means flow out of the engine block. And if the radiator was plugged up with gunk? It should restrict the ability to circulate the coolant.

Truly an odd problem. If not for the fact you've probably done it already, I'd pull the hoses off the radiator and shove a garden hose and flush that out to see what the flow is. Might be possible to run the engine for a while...shut it off.. maybe reach around the fan and 'feel' for cold/hot spots? I'll admit, this one has me baffled.

S-
 

Soledad

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Thanks Tedybear. Since this thing was running the green coolant and I switched it over to the recommended Ford Gold coolant, I guess there is a chance that there was some reaction between the two if I didn't get all of the green out of the system.

I think here's what I'm going to do. Unfortunately I've only got one day off this week and then I'm working another 6 days so I might not get to it for a while.

1. The cooling system pressure tester kit is coming in on May 2 so I'll hook that up and see if the system can hold 14.9 lbs of pressure. If it can then #2.
2. I'll drain the system and pull the radiator hoses and inspect for any weird sludge or gunk/pasty type stuff. If nothing then #3.
3. I'll run the garden hose full blast through the radiator to see what kind of flow volume comes out. If that looks good then #4.
4. I'll pull the thermostat out and throw it in a pot of water and see what temp it opens.
5. Then I'll do a reverse flush and run the garden hose through the top radiator hose without the thermostat installed to see what kind of flow volume I get out of the block. I'd like to do a normal flush and run the garden hose through the bottom radiator hose and run the engine but I'd have to trash the very expensive thermostat to make it work.

After all of that, if there's no pressure leaks, no blockages and the flow volume looks good then I can only guess it's the heater circuit not performing properly.

EDIT 1: Ok, something I forgot about. The temp of the smaller hose (overflow hose) connected to the thermostat is around 170*-180*. The thermostat body has two outlets, the main one and the smaller one. The main one of course is managed by the spring and wax pellet. But the smaller outlet is wide open. The main spring area and the smaller outlet both will see the 170*-180* coolant. Therefore that thermostat is definitely getting hot coolant. Just not 208* hot to make it start opening.
 
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RonD

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There are 2 main anti-corrosion bases used in coolant.

Silicate based, often called "green" but color means nothing any more, lol.
Silicate based works fine and was the original anti-corrosive base, but its protection starts to break down after 2 years, so short flush and change intervals.

Organic acid based(OAT) is the newer base for anti-corrosion, originally it was "red", it has a longer life, 5+ years.

These two bases should not be mixed in quantity, yes that can cause sludge build up.

But not to worry, there is now HOAT, lol, hybrid organic acid technology.
It uses BOTH silicates and organic acid for corrosion protection

Ford Gold should be a HOAT formula so wouldn't cause sludge build up

All of them use ethylene glycol or propylene glycol(non-toxic), for anti-freeze/coolant properties, this never wears out, just FYI.
And they all contain a water pump and seal lube.
 

Soledad

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Ok, that's excellent info! Thanks RonD! That puts my mind at ease regarding the green vs. gold coolant. I did a really good garden hose flush the very first time but I'm sure I didn't get out all 100% of the green coolant especially if there may be a blockage.
 

RonD

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You can't really flush out the silicates, you do need to flush out the older coolant for sure, but the silicates coat the metal parts of the cooling system, thats how they protect the parts, the anti-corrosion.

So flushing won't remove the coating.
When someone switched to OAT base from silicate base the organic acid would remove the silicates often causing the sludge.

HOAT still uses silicates because it offered better protection long term, so no silicate removal short term.

There is also NOAT, NMOAT and POAT now, lol.

And silicate based coolant, the original "green", is now called IAT, inorganic acid technology, because we now have organic acid technology, OAT, HOAT and the rest.


In my opinion, if you have an older vehicle you are better off running "green" silicate based, I know for a fact I WILL get a coolant leak in my older vehicles over time.
And I will most likely have to drain the coolant out and fix the leak, then top it up or refill it.
Do I want to pay for HOAT or IAT?
They both offer the same protection for the first 2 years of use, so as a practical and CHEAP person I use IAT, lol.
 
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Soledad

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Here's how I believe the coolant flows. I'm sure on about 90% of it but the 3-tube bypass hose that runs around the back of the block to the bottom of the degas bottle had me guessing. If anybody sees a mistake please let me know and I'll correct it.

I searched for a few hours but can't find an official coolant system diagram. Heck, I couldn't find one at all. I had one for my 2006 Ford F350 6.0 Powerstroke (that is one well documented engine) but this Duratec 2.3L is lacking a ton of official info online.



And the official and very elusive one:

 
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RonD

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The "green" was used for alot of years and pretty much the whole engine cooling system during that time was cast iron with copper radiators/heaters with rubber hoses and a few steel parts like water pump impellers and thermostats.

As manufacturers started using different metals, like aluminum, the chances for galvanic corrosion increased, but as long as coolant was changed every 2 years protection remained, except not every one does that, and on older engines that wasn't a big issue since metals were the same, with different metals it was a problem.

OAT was developed for longer term protection, 5 years, so problems would occur AFTER warranty period, my own opinion :), if people didn't change coolant when required.

There are all kinds of tests done as to which is better, IAT, OAT, HOAT, ect......., and with which engine models, years and displacement.

I can't say which is better scientifically on paper, but others have done that so I don't need to :)
On vehicle less than 10 years old I tend to go with what manufacturer spec'd for that year and engine.
After that I figure I am going to get leaks, lol, and go with my more practical plan short term protection, not figuring I will get that 5 years at this point, lol.
 
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Soledad

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Man I feel stupid. I had been assuming the CHT temperature was the temp of the coolant in the head. It measures the metal temp of the head.

The cylinder head temperature (CHT) sensor is installed in the aluminum cylinder head and measures the metal temperature. The CHT sensor can provide complete engine temperature information and can be used to infer coolant temperature. If the CHT sensor conveys an overheating condition to the PCM, the PCM would then initiate a fail-safe cooling strategy based on information from the CHT sensor. A cooling system failure such as low coolant or coolant loss could cause an overheating condition. As a result, damage to major engine components could occur. Using both the CHT sensor and fail-safe cooling strategy, the PCM prevents damage by allowing air cooling of the engine and limp home capability.
So, I wonder what CHT temp triggers the fail-safe strategy?
 
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