Over Heating Northstar Engine

I have a 1996 Eldorado which is in mint condition...however it is over heating!! I have taken it to 4 different shops 2 said it was a head gasket or craked block. 2 said it was computer failure. The cooling fans do not work when it gets hot but when I turn on the AC or Heater the fans come on. The fans should come on when the engine is hot...right? Anyone have the same problem? Please help...the dealership said it will cost me 4100.00 to fix it . Thanks for your help.

It sounds like you might have two problems.
 
If it IS a head gasket, check your oil and radiator for discolorations, oil will be turning yellow and foamy, radiator will have what looks like sludge.
 
Could be the temp switch for the fans, that you should be able to do yourself, the switch is usually about $20-$50 at Autozone.
 
It could also be the computer. Does your check engine light come on? If it does, Autozone can check it for you and tell you what troublecodes your car is throwing.

God bless AutoZone 

good advice above ..
below is a list of threads that may also help, with special attention to the  "coolant threads".

quote:

ORIGINAL: stomper



The BEST car Cadillac ever made is the ..  you get to pick.
http://www.cadillacforum.com/m_9438/tm.htm

MY Cadillac has more miles than yours thread .. Lets get the 400,000 mile cars.
http://www.cadillacforum.com/m_12353/tm.htm

CODES .. Pulling & understanding CODES .. we need CODES to help you. 
http://www.cadillacforum.com/m_18197/tm.htm
http://www.cadillacforum.com/m_17425/tm.htm
http://www.cadillacforum.com/m_11904/tm.htm

Community Services: Auto parts, Vehicle Taxes, highways cams, picture capture,
Corp 800 #’s, unique shipping services .. etc ... take a look.
http://www.cadillacforum.com/m_9880/tm.htm
                          
Average age of our Cadillac owners .. where everyone says they are 23.
http://www.cadillacforum.com/m_931/tm.htm

Why you should change to coolant the day you buy the Cadillac.
http://www.cadillacforum.com/m_7193/tm.htm
http://www.cadillacforum.com/m_7388/tm.htm

Transmissions or Engines - why you do NOT FLUSH the 4100 & 4500 drive trains.
http://www.cadillacforum.com/m_6036/tm.htm

Cadillac GM e-ghosts electric problems, intermittent codes, etc.
http://www.cadillacforum.com/m_6068/tm.htm

Help from our TECHs ?  You really want to read this.
http://www.cadillacforum.com/m_9792/tm.htm

Cadillac TECH   FAQ   MENU .. pull up all the FAQ topics
http://www.cadillacforum.com/m_6733/tm.htm

Cadillac Technical FAQ section .. everything Cadillac
http://www.cadillacforum.com/forumid_64/tt.htm

Cadillac Allante  TECH   FAQ .. things that the car needs often, owner’s manual, etc.
http://www.cadillacforum.com/forumid_83/tt.htm

The Cadillac Allante Pub - discuss, argue, and laugh .. Allante  not needed to jump in.
http://www.cadillacforum.com/m_21055/tm.htm

Allantesource.com  Allante  PROCEDURES MENU .. issues that few know how to handle
http://www.cadillacforum.com/m_18287/tm.htm

Hobby Corner .. Hot wheels, trains, whatever ..
http://www.cadillacforum.com/forumid_60/tt.htm

Cadillac History .. The real McCoy, from day one.
http://www.cadillacforum.com/m_6356/tm.htm


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My guess on this one would be, a coolant temperature sensor, bad fan, or, wiring issue. How many fans does it have? On a lot of cars one or more fans come on when the AC is turned on but the AC doesn''t always control the same fan as the temperature sensor. Find out if the fan comes on if you unplug the coolant temperature sensor. If it does, then there''s a good test to see if the fan works.
 
Also, some cars have the ablity to run a KOEO test through a tester. The ones I''ve used test the fans and some also test the sensors.
Good luck.