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Discussion Starter · #1 ·
I have a 97 Lincoln Continental 4.6L DOHC that is over heating.

The car will idle for hours and cruse up to around 45 MPH with no problems. From there up the temperature will climb with the speedometer and eventually I get an hi-temp warning. If I let off and coast down the temp goes right back to normal. Holding a steady speed at 50 to 60 MPH will cause the temp to go up high.

So far I have replaced the entire cooling system; water pump, thermostat, hoses, belt, tensioner, radiator, temp sending unit, and cooling fan motors. I even removed the water pump and tack welded the impeller to the shaft (thinking it might be slipping)

Thinking it might be an engine management issue (maybe running lean) I also replaced all 4 O2 sensors,installed a new throttle body, TPS, Traction Control Motor, TC Position Sensor, and swapped out the ECU.

No codes show up. I am not losing coolant; no water in the oil an no oil in the water.

The engine runs fine. No pinging or power loss. Exhaust flow at the tail pipes seems to be normal, however the exhust temp seems to be somewhat elevated.

So I am out of ideas. Anyone have any suggestions?

Thanks in advance.
 

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Have you run the car with a proper scantool or some other device to check/confirm that the coolant temps are really fluctuating like that?

And btw, are you saying that when it gets really hot like that, it DOESN'T lose power - or ping when you give it a little throttle but not enough to downshift.

Modular's don't like running hot - if it still runs perfect even when your dashgauge says full hot it makes me wonder.

edit: more random - has the car had front end damage? You don't have any body work or custom spoilers, right? no intercooler mounted ahead of the radiator, right?
 

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Discussion Starter · #3 ·
Have you run the car with a proper scantool or some other device to check/confirm that the coolant temps are really fluctuating like that?

And btw, are you saying that when it gets really hot like that, it DOESN'T lose power - or ping when you give it a little throttle but not enough to downshift.

Modular's don't like running hot - if it still runs perfect even when your dashgauge says full hot it makes me wonder.

edit: more random - has the car had front end damage? You don't have any body work or custom spoilers, right? no intercooler mounted ahead of the radiator, right?
Thanks for the reply

I have not use a scantool to double check the reading.

I have not run it at the elevated temps to see if it pings, etc. When the temp starts to rise I back off and coast down to 40-45 and the temp drops to a safe level.

No on all the random. Car is stock and never wrecked.
 

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Have you replaced the GAUGE itself. I see you list the sender. Could be wiring I suppose.

You could run a proper aftermarket gauge (like an Autometer or something) temporarily, so that you could confirm. It might be that, since you're replaced the sender, you could run a new wire from that into the car, temporarily, and hook that to the aftermarket gauge.

Sell the gauge on the internet if you don't want it after you're done.

Or find someone/someplace with a scan tool and tell them what's going on, etc. and that you would like to pay them for the diagnostic time necessary to go for a quick ride with you while you duplicate the conditions.
 

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Does it have any mods? When did this start? Do anything at that point? Electric fans right, they would have to not kick on to overheat I would think. Timing could be too low at the 1500rpm point and above if tuned at all. 40-45mph would be about the speed for 1500rpm.
How about running the heater when it gets hot, does that lower then temp?
Just throwing somwethings out there, tough to diagnose this by posts. The wiring sounds viable as it sounds like the motor is running fine. Low timing is one thing that will cause hot running. Checked the plugs for color?
 

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Discussion Starter · #6 ·
Have you replaced the GAUGE itself. I see you list the sender. Could be wiring I suppose.

You could run a proper aftermarket gauge (like an Autometer or something) temporarily, so that you could confirm. It might be that, since you're replaced the sender, you could run a new wire from that into the car, temporarily, and hook that to the aftermarket gauge.

Sell the gauge on the internet if you don't want it after you're done.

Or find someone/someplace with a scan tool and tell them what's going on, etc. and that you would like to pay them for the diagnostic time necessary to go for a quick ride with you while you duplicate the conditions.
The gauge on the Lincoln is an integral part of the "projector display panel" I do not believe it is replacable by itself. Also the diagnostic panel gives a Engine Hi-Temp warning in addition to the gauge reading.

I have not found another location for a manual gauge, and since the temp sensor is used by the ECM to regulate timing and fan speed, etc I can't remove it to put in a manual sensor there.

I guess I'll have to get someone to ride with me with a scan tool to see what shows up.
 

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Discussion Starter · #7 ·
Does it have any mods? When did this start? Do anything at that point? Electric fans right, they would have to not kick on to overheat I would think. Timing could be too low at the 1500rpm point and above if tuned at all. 40-45mph would be about the speed for 1500rpm.
How about running the heater when it gets hot, does that lower then temp?
Just throwing somwethings out there, tough to diagnose this by posts. The wiring sounds viable as it sounds like the motor is running fine. Low timing is one thing that will cause hot running. Checked the plugs for color?
This is a completely stock car with no mods. The car has 180K miles on it and the Temp problem happened all at once. The electric fans seem to be functioning OK but obviously I can not verify that they are running while the car is at 50 MPH. Maybe I can get my wife to take a ride on the fender (LOL).

However, I have immediately pulled over after getting a Hi-Temp warning ant the fans were running. I don't really know how much they realy add above 40 MPH. On most cars you don't need a fan at highway speeds.

As you know timing is completely controled by the ECM on this engine, so if timing is a problem, then it must be sensor related. That's why I replaced all the sensors that I thought would be involved. Maybe I missed some. Do you have any ideas which ones to check out?
 

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So you had this car for awhile and it DIDN'T do this, correct? Has it lost power? Does it seem to lose power when this is happening? You did say you swapped the ECU, correct?

Have you immediately pulled to the side when it's been "hot" like this and checked under the hood? Besides the fans running, did it seem really hot?

I lost a fan once on a morning commute. Close to full hot was seriously noticable in the negine compartment (over operating temp). Of course, the fan wasn't running, but still.

EDIT: I second the above Q from 99GTAUTOVERT: does it effect your heat?
 

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Discussion Starter · #9 ·
So you had this car for awhile and it DIDN'T do this, correct? Has it lost power? Does it seem to lose power when this is happening? You did say you swapped the ECU, correct?

Have you immediately pulled to the side when it's been "hot" like this and checked under the hood? Besides the fans running, did it seem really hot?

I lost a fan once on a morning commute. Close to full hot was seriously noticable in the negine compartment (over operating temp). Of course, the fan wasn't running, but still.

EDIT: I second the above Q from 99GTAUTOVERT: does it effect your heat?
Yes I have owned the car for about 7 years. It does not seem to lose power. I did swap the ECU. I have checked the temp with a hand held infared sensor and the temp at the crossover tube is about 220 degrees. Heater works fine. So does AC.
 

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Discussion Starter · #11 ·
I wonder if you have all the air out of the coolant system. Have you tested the cap.
The Lincoln has what they call a Degas Bottle. I have not tested the cap but the system does hold pressure.

I bled the system by removing the plug in the top of the cross over tube. It does not appear to have any air trapped in the system However this set up is hard to purge so I have checked it several times to make sure, and I think I have all the air out.
 

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Some times parking it on a hill (nose up) will allow you to remove more of trapped air in the system. I have 2 Mark Vllls and they can be troublesome to get air out fully. Any crimps in the lower hose?
 

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Discussion Starter · #13 ·
Some times parking it on a hill (nose up) will allow you to remove more of trapped air in the system. I have 2 Mark Vllls and they can be troublesome to get air out fully. Any crimps in the lower hose?
Thanks for the reply

No crimps. New hose too.

My driveway has a pretty good slope to it. I followed the Shop Manual instructions to purge the system and in addition pulled the plug in the cross-over tube and fill from there until all air was out of the system. Started the engine with the plug out and verified full coolant flow on the cross-over tube. Do you have another way to purge it?
 

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I wonder if some how the thermostat isn't functioning properly. Did you notice good flow when you looked in the cross over tube? Also just for grins get the cap tested as it may not be doing it's job.
 

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Discussion Starter · #15 ·
I wonder if some how the thermostat isn't functioning properly. Did you notice good flow when you looked in the cross over tube? Also just for grins get the cap tested as it may not be doing it's job.
New thermostat - That's the 1st thing I tried. Flow seemed OK in the cross-over. COuld not run it much with the plug out because it just pumped coolant out.
 

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Personally, I would try flushing the system REALLY GOOD. All it takes is a little rust to plug a pass in the rad. Also, scale in the cooling jackets limit thermal transfer. My 89 Marq had the same symptoms. Was a bad rad. One thing I've learned through the years also "just kuz it's new don't mean it's good". All else fails, try a bottle of "Red Line Water Wetter".
 

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Yes I have owned the car for about 7 years. It does not seem to lose power. I did swap the ECU. I have checked the temp with a hand held infared sensor and the temp at the crossover tube is about 220 degrees. Heater works fine. So does AC.
ok wait - that's what it is when the linked-up (as in the gauge and the light aren't likely from separate inputs) dashboard display is telling you it's seriously hot ? Have you compared that reading known operating temp to hot?

Just a suggestion using the handheld scanner:

Take temp readings of that crossover; of an exact spot on each side of the motor (maybe one exhaust manifold "primary tube" close to the head and something else on the other side); pump at the front somewhere maybe.

Take the temps when warmed up and at operating temp. Run it into the hot zone for a bit, immediately pull over and record them again.

Two weird suggestions given that, from your list, you've replaced pretty much everything:

Can you figure a way to use a jumper-wire from the sensor to the ecu input - and bypass the wiring harness?

This only happens after an extended highway run or sustained acceleration, correct?
Are the cats original? There's still the counter-fact that you notice no power-loss when this is happening, but hey, just throwing stuff out there.

NOTE: I'VE HAD A BRAINSTORM-FART MID-POST:
Does that engine have charge-plates, or variable-runners, or MDwhateveryacallit "technology". You immediately pull over when this happens and it cools off, so you might not be running it that way long enough for the ecu to sense/catch/call the lean condition and tell you this is the problem.

The computer's not so precisely reading/parsing the a/f off the O2 (in real time) to decide how much fuel to add - it's more based on the tps, etc. and if the computer thinks, at that throttle position, that mph, that gear, etc - the engine should only be getting so much air because the plate to the other runner should be closed, and it's actually staying open . . .

just brainstorming here, but someone probably ought to light a match, I was up late last night and this might just be gas.
 

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Discussion Starter · #18 ·
This only happens after an extended highway run or sustained acceleration, correct?
It deos not take much of a run. About 2 miles to get out of our sub divusion and then about another 2 - 3 mikes at cruise. Then any acceleration (even part throttle) that increases the speed above 45 - 50 MPH will cause the temp to increase.

NOTE: I'VE HAD A BRAINSTORM-FART MID-POST:
Does that engine have charge-plates, or variable-runners, or MDwhateveryacallit "technology". You immediately pull over when this happens and it cools off, so you might not be running it that way long enough for the ecu to sense/catch/call the lean condition and tell you this is the problem.

The computer's not so precisely reading/parsing the a/f off the O2 (in real time) to decide how much fuel to add - it's more based on the tps, etc. and if the computer thinks, at that throttle position, that mph, that gear, etc - the engine should only be getting so much air because the plate to the other runner should be closed, and it's actually staying open . . ..
No varialbe runners or charge plate on this engine. Just a basic 1997 4.6L DOHC 32 Valve Intech in my Linclon.

Is there anything else in the Engine Management other than the TPS, O2 sensors, and water temp sensor that could affect the A/F ratio to cause a lean condition?
.
 

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Air in System

It still sounds like you have air in lthe system. Run the system with the cross over tube plug off until water comes out and then leave the plug off over night. Putting the car up on ramps often helps to move the air out the plug.

Glenn Ford
 
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