: N* Water Pump...I think

03-31-08, 12:21 AM
Just looking for some moral support on this one. I'm very familiar with the 4.x engines, but never worked on a Northstar before, so those of you who have...

This is for a 97 Deville. I was on the highway, and all of a sudden I see "engine hot," "idle engine," then "engine overheated," "stop engine," all while I was still in the process of pulling over. I shut it off as fast as I could, and turned the key to the AC position to see the coolant temp, and it was around 250-something :bomb:. The oil life also went immediately to 0%, but I checked it at the stick and it looked fine; I'm assuming it did this because oil temperature is a factor in the oil life.

So I let it cool down, and had a fun 6 hours of doing that and coasting to where I needed to get in order to avoid being gouged by a towing bill. I checked the coolant level after it cooled down, and it needed a bit, but I soon found out that wasn't the problem. I checked under the car--no drippage. I checked the cap again, and the coolant was still up to it, so it didn't leak away, and no headgasket suspicions.

I checked and also found I had no heat. So basically...it happened rather suddenly, it has coolant, there's no heat, and the engine overheats quickly, oh, and the upper radiator hose was hot, so I don't think it's the thermostat stuck closed or something. So me thinks the water pump went. There was one rogue code in there, but I forget. If it would help, I'll post it, but I'm assuming it's just telling me it overheated. It was P12____ something like that.

So my questions--anyone disagree and think there's something else it could be besides the water pump? The only thing I could think of was a blockage in the system, but it didn't seem likely that it would prevent engine cooling and cabin heat. Also, as I recall, this blasted car requires a special tool just to get it's water pump off--can I get that at a typical place like Advance Auto?

If we all agree this is definitely the water pump, could someone give me a basic run-down of the procedure for this? Actually, a link to another thread would be just fine since I'm guessing this one's been covered. I apologize for not searching this, but I'm completely whipped from all the coasting tonight. I haven't...until now :bigroll:...been *ahem* motivated to get a factory service manual for this car... It's just approaching the 100,000 mile mark. I have no knowledge if this was replaced or not, as I bought it last year, and I've put about 20,000 on it.

03-31-08, 12:38 AM
Is the belt and the tensioner still on the water pump?

03-31-08, 11:21 AM
Aye...so used to the other engine, I just looked at the serpentine, saw it was ok, and yeah...:bang2: But I looked around the driver's side rear of the engine, and I can't even find the stupid thing. In typical Caddy fashion, there is about 1 inch of spare room on every side of the engine. I looked down there, and I didn't see any belt or pump... Do you have to look from under the car to see it on this? What a pain... I'm not going to dive in just yet because it's cold and pouring outside...go figure :ill:

Mark C
03-31-08, 12:24 PM
Water pump is on the drivers side front, just above the thermostat housing. Its driven off the rear (transmission side) of the engine from the bank 2 (front of car) intake cam by a short belt (maybe 10 to 12" long total, by 1/3" wide) under a metal gaurd. If the pump is turning check for a plugged purge line (the black platic line that runs under the silver beauty cover over the intake manifold) between the water pump housing and the coolant overflow tank. If it is plugged the system won't purge any air from the system and it will end up air bound eventually. This causes the heater to not work. If you disconnect the line at the overflow tank (carefull do it with the car cold, and don't break the barb off the tank) and run the car there should be a flow of water coming out the open end of the tube that varies with engine RPM.

03-31-08, 01:42 PM
Thanks--that description was very helpful. Didn't see the little bugger right in front of me. Anyhoo, turns out the belt simply broke. That's the kind of fix I like to find :bouncy:. I'll put my common sense hat on next time, thanks again.