tmars131

93 SEVILLE W NORTHSTAR BOILING COOLANT

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Hello,

New to caddys I use to work on highway trucks working on cars now got down sized. First time on a caddy $#$%% GM MUST HAVE BEEN DRUNK everything is so tight!!!

Here we go-

93 SEVILLE W NORTHSTAR BOILING COOLANT ONTO GROUND BECAUSE ELEC COOLANT FAN WILL NOT RUN (EVEN AT 225+ TEMP) the fan next to battery (passager side) comes on with AC on, but not the drivers side.

WHAT SWITCH/SENSOR OR RELAY COULD THIS BE------???

I have removed both fans and bench check both works.. Car at normal temp. on highway but not in city runs hot..

can someone please help?

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Go to the top of this page, click HOW TO, then DTC Codes, and follow the directions for your year and post the DTC codes here, the fan relays will set a code

Check your thermostat, change it if you see any binding

Check to see that you have at least a 50/50 mix of coolant concentration

Check your cap to see that it holds pressure

Check your system to see that it holds pressure

Check your water pump belt to see if it slips and that the tensioner is applying pressure

Check your purge line to make sure that it is flowing coolant, and allowing air out of the system


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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PS, yes the Northstar platform is tight, but its logical, its a system and built as an integral unit. It would help if you had a factory service manual.

As I noted there are three relays. Its possible that you have a problem with one of them. Your AC is forcing the right fan on. Typically turning the AC on forces the fans on. With the AC off, the fans will remain off till about 228 degrees, when the temp drops to 217 degrees they will turn off.


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Check your thermostat, change it if you see any binding (CHECKED OK)

Check to see that you have at least a 50/50 mix of coolant concentration (OK)

Check your cap to see that it holds pressure (OK)

Check your system to see that it holds pressure (OK)

Check your water pump belt to see if it slips and that the tensioner is applying pressure (little lose)

Check your purge line to make sure that it is flowing coolant, and allowing air out of the system (OK)

I JUST GOT BACK FROM TEST DRIVE Outside temp is about 75 deg - car temp got up to 235 deg, still no fan

turned on AC temp droped to 217 still 1 fan only. Where are the fan relays located they are not under the rad I replaced the rad 2 days ago side tanks cracked..

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With the key off and hopefully the engine not hot -- and certainly not overheated; just wait if necessary -- open the hood and turn each fan and see if they both turn easily. If a fan doesn't turn easily, make sure that nothing has gotten into the fan blades (leaves, whatever) and if that doesn't do it then either the bearings or motor on that fan is bad.

Given that you have two good fans, the next test is, again with an engine that at least is not overheated, start teh car and turn on the A/C. Both fans should be running at LOW speed, even with a cold engine. If not, shut her off and we have an electrical problem to troubleshoot.

If the fans don't run on LOW with the A/C on, check the fuses. My 1997 FSM, page 6-176 at the beginning of the section on Engine Cooling has a schematic of the cooling fan circuits. There is a master fuse in the RH MaxiFuse block, which is under the hood under a plastic cover behind and below the air cleaner, near the fender well on the driver's side. It is a large 50 Amp MaxiFuse labeled COOL FANS.

There is another fuse in a block of smaller fuses under the same cover. It is a regular 10 Am fules labeled AC COMP. If it is not good the fans will not run, so check it.

It it is good, we go to the fan relays, which are all together on the plastic frame that mounts the fans, on the engine side, at the bottom center. See if there is 12 Volts on the RED wire to two of the three relays, and to the ORN wire to all of them.

Next, check to see if you have a good ground to the BLK wire to two of the three relays. The last check is a resistance check across each fan motor; this resistance should be low, under 20 Ohms.

If you have 12 Volts on all the RED and ORN wires and a good ground on the BLK wires and the fans are good, then you have one or more bad relays. You can check them too by looking at voltages when they are in the fan LO and HIGH speeds, but the simplest thing to do is to switch them with known good relays. Likely it's only one relay. I would suggest getting one new relay at an auto parts store and switching with each in turn to find the bad one.


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-- 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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Check your thermostat, change it if you see any binding (CHECKED OK)

Check to see that you have at least a 50/50 mix of coolant concentration (OK)

Check your cap to see that it holds pressure (OK)

Check your system to see that it holds pressure (OK)

Check your water pump belt to see if it slips and that the tensioner is applying pressure (little lose)

Check your purge line to make sure that it is flowing coolant, and allowing air out of the system (OK)

I JUST GOT BACK FROM TEST DRIVE Outside temp is about 75 deg - car temp got up to 235 deg, still no fan

turned on AC temp droped to 217 still 1 fan only. Where are the fan relays located they are not under the rad I replaced the rad 2 days ago side tanks cracked..

What was the result of the CHECKING the CODES? The coolant sensor can cause problems

A little LOOSE on the belt is not good, can you see if the belt is shiney?, indicating that its slipping?


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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No body seems to want to say it. Get a block test kit from Napa and test the coolant for the presence of exhaust gases. Either condemn or rule out a head gasket before you go on a fishing trip.

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