Overheating issues with northstar motor
Asked by Alan Aug 24, 2021 at 06:33 AM about the 2000 Cadillac DeVille Sedan FWD
Question type: General
I am having some overheating issues and have
cleared all the upper lines, including the removable
inlet tube near the thermostat. I have a new
radiator (since I broke the outflow removing the
fans) I think it may be related to the coolant lines
that attach to the alternator. Will I damage
anything bypassing these connections?
9 Answers
the car is a bit old... I'd consider the temperature control sensor
The head bolts are probably pulling out of the block. There is a fix but I doubt the car is worth the cost.
Not the head bolts. It's a coolant flow issue.
How do you know? The head bolts are a common point of failure on the NS engines.
F_O_R, I am very aware of this potential. This issue never occurred until I replaced the alternator. The head bolts, therefore are a very unlikely issue. This is why I am asking about bypassing the coolant flowing through the alternator. I wanted to see if there was a critical function of the coolant extending the life of the alternator. I am trying to troubleshoot the coolant flow as a whole, and one of the hoses connecting to the alternator is kinked, thereby restricting free flow.
There's no way to bypass the coolant flow through the alternator. It's designed to be cooled by the engine coolant flowing through it. If the hose is kinked you either have the wrong hose on it or the wrong alternator. But F_O_R is right about the heads. Before putting too much money in this vehicle test the coolant for combustion gases. Unless you know the head gaskets have been done already, with the button kit, etc., etc., etc. Hope that helps! Jim
Well, let's see...it only overheated after changing the alternator. You tell me what changed. Does that point to the headbolts? I am aware of that issue and did not have issues with losing coolant.
Ok, that's good. Did you compare the old alternator to the new one? Is it "clocked" the same? That is, are the mounting bolt holes in the same position? Are the hose connections in the same position? A lot of times many different applications for different vehicles get lumped together under the same aftermarket cataloging part number. When originally each year and model had a specific part number. Some times it makes a difference, other times it doesn't. The alternator, if you bought a rebuilt one, could be boxed wrong. It happens sometimes. Another thing to be mindful of when dealing with a Cadillac is that some parts are Cadillac only. Meaning that if you don't buy a Delco replacement, it's not going to work or fit correctly. I've owned several Cadillacs over the years, from a '66 Calais Sedan to my current '94 Fleetwood Limousine, and I've run into that problem more than once. I would say that if the hoses were not kinked before you replaced the alternator but now they are than the alternator is wrong. This is also why I never turn in the core until I'm absolutely sure the new part is right! Hope that helps! Jim
I hope for your sake it is not the head bolts. You could do a combustion products test on the coolant to rule that out. Good luck.
