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'97 Eldorado overheating at random times, please help.


sreeder

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Here's the deal, my 97 northstar has been getting hot and not sure what to do. Replaced the thermostat, did not get a flush kit but drained the system and ran a ton of water through it with a hose. It has been doing ok at highway speeds. I can drive like half an hour on the highway and then come to a stoplight and sit and the temp starts rising and my oil pressure light flashes off and on. Seems to overheat at a a stand still. on the other hand, i started it and let it idle for 30 minutes in the driveway and it was fine. Oil is not milky so I do not think this is related to head gasket problems. Now I am at a loss. Any help or advice would be much appreciated.

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There is no credible path between oil and water in a Northstar other than a leak in the oil cooler in the right radiator tank. You won't see water in the oil because when the oil cooler leaks you will more likely see oil in the water.

Your problem sounds like the cooling fans aren't coming on. You can run the OBD codes and help us diagnose the car. Turn on the key, and with or without the engine started, look at the A/C buttons and press <Off> and <Pass Warmer> together until all the dash lights come on like you just turned on the key, then release both buttons, The OBD codes will scroll on the DIC. When the computer is done, it will stop with the prompt "PCM?" You can press <Off> to re-start the code list to catch any you didn't have time to write down. When you are done, you put the car's computer back in the normal mode by pressing <Auto> (the big temperature knob - it pushes in), pressing Reset Info, or turning off the key.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Drove on the highway for about twenty minutes and it overheated. Then let cool down and drove home for about. 20 minutes at 45 mph with no problems. Unless noted current, all codes I pulled were history

PCM b0113current, b1111 current , b0325,b0102 b1599

Ipc b1552,1983,2510

Acm- b1348,1350

Tcs c1255

Rss-c1712 current, 1711,1760

Pzm- b1552,1983,2470,2502,1558,1970,2477

Msm- b0856,b2129,b2120 current,b2119,b1983,u1300

Mmm- b1983.

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PCM
P0113 Intake Air Temperature (IAT) Sensor Circuit High Voltage
P1111 Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage CURRENT
P0325 PCM Knock Sensor Circuit
P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency
P1599 Engine Stall or Near Stall Detected

IPC
B1552 ?
B1983 Device Power Circuit Low
B2510 Steering Wheel Controls HVAC Key Stuck

ACM
B1348 Very Low A/C Refrigerant Pressure
B1350 Engine Coolant Over-Temperature

TCS
C1255 EBCM Internal Malfunction (ABS/TCS Disabled)

RSS
C1712 Left Front Damper Actuator Open Circuit CURRENT
C1711 Left Front Damper Actuator Short Circuit to Ground
C1760 Left Front Position Sensor Input Fault

PZM
B1552 ?
B1983 Device Power Circuit Low
B2470 Daytime Running Lamps Fault
B2502 Auto Trans Shift Lock Control Shorted to Ground
B1558 BCM EPROM Checksum Error
B1970 Exterior Lamp Power
B2477 Reverse Lamp Relay Shorted to Ground

MSM
B0856 Battery 2 Out of Range
B2129 ?
B2120 Lumbar Up/Down Sensor Failed CURRENT
B2119 Lumbar Forward/Aft Sensor Failed
B1983 Device Power Circuit Low
U1300 Class 2 Short to Ground

MMM
B1983 Device Power Circuit Low

A lot of these indicate low battery voltage. Check the battery charge and condition, and the battery cables. Then, reset the codes and see what comes back.

The B2120 is probably caused by the lumbar adjustment being set against one of the stops. Move the lumbar adjustment away from the stop and the CURRENT code there will probably go away.

The P1111 is probably because the plug on your IAT sensor is loose. That's the small plug on the side of the air cleaner housing.

The C1712 means that the connector to the left front strut is unplugged.

None of these are fan codes. That doesn't mean that the fans are good, just that whatever is happening isn't throwing any codes. You can do a quick check on your fans the first thing in the morning with a cold engine by popping the hood before you start the car. Start the car and make sure that the A/C is ON, then get out and look. Both fans should be running at low speed. If either or both fans are not turning, you need to go after that first.

One suspect in any overheating problem, particularly an intermittent one, is the bypass from the crossover back to the surge tank. You can check this by finding the hose that connects between a metal hose that goes under the beauty cover to the side of the surge tank. Take it off at the surge tank and start the car; it should flow freely. If it's stopped up, it's probably at the other end, at "the bolt with the hole" fitting into the crossover housing.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Well I attempted to check the metal line from the surge tank and the car went crazy on me when I unlocked the door. Horn started sounding alarm, at a very low tone because of dying battery , gas cap flew open, trunk came open? Very odd wonder if there is a short somewhere. Battery hasn't been holding a charge for the last few days so maybe it's getting drained .

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I attempted to start the car but it went a little crazy on me when I unlocked the door this morning, I can tell the battery is low and the alarm sounded at a low tone and finally stopped, then the gas cap flew open along with the trunk lid. Not sure what is causing this but now is another problem maybe a short,

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A large number of the codes you posted were thrown because of low battery voltage. You need a good battery, fully charged, with good battery cable connections, before you can diagnose electrical problems. You can start with the disconnected left front strut and the loose or disconnected IAT sensor on the air cleaner housing. Beyond that, you will need a good battery to tell much of anything.

If the battery is just down, you might try a trickle charger or a battery maintainer from the auto parts store. Leave it working overnight, and try again when the status LED on the charger tells you that the battery is fully charged.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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You definately have a battery connection issue. Especially check the 2 red cables to the battery as there is supposed to be a part between the terminals and sometimes it gets dirty/corroded or missing completely

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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