09-10-04, 10:51 AM
My friend has a 2001 Deville that has an overheating problem. The car was at the dealer's where they changed the sensor and the thermostat but the problem continues. I will explain the problem as he explained it to me. The dealer told him that because the problem was neither the sensor or thermostat they would have to open the engine (which they said would be at least 30 hours * $100) to see what was wrong. They advised him to get a new or used engine for the car and have it replaced somewhere outside the dealer because it would be cheaper. These comments alone make me very suspicious. My friend also says that the car overheats within the first 10 minutes of him starting it in the morning. After it overheats he turns it off and after 5-7 minutes it shows the temp is back to normal (this to me sounds very fishy). I suggested he get a second opinion from another dealer before he goes out and buys an engine. But he doesn't have much money to spend and he fears that the second dealer will tell him the same thing.
I hope I have explained the problem well since this is my first post.
PS. The car has been used for limo service since he bought it new and has had all of its scheduled maintenance done at the same dealer where he bought it.
09-10-04, 11:37 AM
Just out or curiosity, how many miles are on it? Also, read through the following post for information that pertains to this situation:
You might also use the forum search feature in the tool bar above. Type "overheating" or "coolant" or "coolant supplement" or "vapor vent hose" (etcetera) into the drop down box and read through the discussions.
Several things can lead to overheating that are easy to check. Coolant concentration, the water pump drive belt and drive belt tensioner, the vapor vent hose flow as described in the other posts, coolant level, etcetera.
Does the coolant level in the surge tank drop and/or does it require frequent additions of coolant to keep the system full? Has the cooling system been maintained and the coolant supplement added to keep the system sealed?
09-10-04, 12:30 PM
The car has 128k miles.
09-11-04, 12:22 AM
I don't know how the 2000+ devilles handle air in the cooling system... I assume there's something in the highest point that flushes air out.. But it REALLY sounds like you've got an air bubble in the system. That's just about the only thing that would cause it to overheat, and be "normal" 5 minutes later. Possibly as Geno said, the water pump drive system could do that as well.
Unless there was a big change in 2000, the air is purged by the vent line that runs from the pump across the top of the motor along the left cam cover to the surge tank. The "back to normal in 5 minutes" kinda sounds like an indication problem. I would definately get a second and maybe 3rd opinion.
09-11-04, 01:28 PM
All Northstar cooling systems are self purging of air as long as the vapor vent line mentioned is free and clear and not modified/plugged. That's the reason to check it at the surge tank for flow.
09-13-04, 12:20 PM
Thanks for all your suggestions.... unfortunately I am no mechanic and can't really check all the suggestions out. We live here in New York City. Does anyone know any good Cadillac mechanic in the area other then the dealership?
09-21-04, 12:43 PM
My friend got a second opinion from a Cadillac machanic. He needs a new engine :helpless: Where can he get a used 2001 northstar engine vin Y?
09-21-04, 05:59 PM
An old timers trick is to add some Rit clothes dye to the coolant. This will leave a residue at the point of leakage that anyone can spot. Pick a color that will contrast with the coolant color to prevent confusion with an old leak.