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Eric, Automotive Repair Shop Manager
Category: Car
Satisfied Customers: 32372
Experience:  Automotive Repair Shop Manager, Technician/JA Mentor
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What could cause this coolant system problem with my 1998 Cadillac Deville

Resolved Question:

1998 Cadillac Deville
199,000 miles
I have a serious leak in the coolant system. Additional information:

Two days ago I noticed a whirring noise that sounded like a motor, but not the engine.

Several times now in the last week, my car has completely shut down while I was driving.

This evening, the "CHECK COOLANT LEVEL" message appeared. Then a few other messages appeared: "ENGINE OVERHEATING", "IDLE ENGINE", "TURN AC OFF", and "CHANGE ENGINE OIL". Also the Service Engine Soon light came on.

I found a profuse coolant leak near the front of the car on the driver's side.

Can a coolant leak...
1. ... cause noises such as I'm hearing?
2. ... cause the car to suddenly shut down with no dashboard messages?
3. ... cause the "CHANGE ENGINE OIL" message to appear?
4. What are the things that could be leaking? Could the problem be a loose hose?
5. What is the maximum possible cost to fix this?

Thank you.
Submitted: 8 years ago.
Category: Car
Expert:  Eric replied 8 years ago.



Lets first try to find source of leak. Take a look a photo below. Does leak appear to be coming from where the red arrow is pointed to (yellow highlighted area):


Customer: replied 8 years ago.
The leak does come from that side, but at the bottom. I did not note anything leaking near the top of the engine. Also, the picture you sent does not look exactly like my engine compartment.
Expert:  Eric replied 8 years ago.



You need to have a cooling system pressure test to confirm leak, but I strongly suspect the water pump has failed.


Water pump is located on the left side of the engine compartment at the end of the engine block:



Without a cooling system pressure test being done, its almost impossible to verify source of leak unless it is obvious.


When the "engine overheating" light comes on, the "idle engine" and "turn AC off" lights will come on to instruct the driver to do these things in order to help cool engine off.


The "change engine oil" may have come on due to engine oil thinning because of engine overheating, it may have come on if headgasket is blown and coolant is in the oil, or it may have be a computer glitch.


The "service engine soon" light will come on when the engine overheats.


Anytime the engine overheats, especially on these Northstar engines, you have to be concerned about the headgaskets blowing. I have seen this many times on this engine.


The whirring noise is probably from the water pump or water pump belt breaking as a result of water pump going out. Or the belt broke and caused and the pump to go out- can happen both ways.


At this point, I dont advise driving it. It needs to be tested for source of leak, as well as a "block" test done to determine if combustion gases are present in coolant(blown headgasket).


Depending on source of leak, water pump can run $300 parts and labor, while a hose would be substantially less. Blown headgaskets will run over $1200 arts and labor-more if heads need machine work.



And yes, a severe coolant leak can cause an engine to shut down immediately to prevent further damage

Eric and 8 other Car Specialists are ready to help you
Customer: replied 8 years ago.
It turns out that the whirring noise was the alternator. The coolant leak was from the radiator (drain cock, I believe). Finally, the EGR valve is stuck, which could be a result of the overheating.