Alternator?

[mxer147]

Daily driver water pump seized and it spewed coolant everywhere and smoked the belt some. After replacing it, it didn’t want to fire up and run properly but I figured I tripped a bunch of codes when I moved the car without the serpentine belt connected. I eventually got it to start and run properly so I took it to the car wash for an engine compartment deep clean. It ran fine home and a few more time’s moving it on the street. Today, it struggled to keep running after it started and I noticed the voltage gauge moving around quite a bit and the engine stalls when it drops to 9 volts or less. Does this read like it’s an alternator issue? I didn’t pop the hood and test anything. I figured I would ask you knowledgeable folks. It’s a 3.8 liter Pontiac v6 so the alternator is easy access.

 

[Ricko1966]

Disconnect the positive lead off the alternator see if it will run on just the battery.

 

[fast 99]

Disconnect the positive lead off the alternator see if it will run on just the battery.

Vehicle year unknown.
That is an old way of checking alternator output [works] and is not recommended on ECM controlled vehicles. Moment the cable is disconnected voltage spikes and could damage electronics.

Yes coolant can cause alternator failure. However, with engine off spraying the alt with water could clean it out internally. Should check voltage with a meter. Make sure the pully isn't slipping. Usually alternators will recover out but not always.

 

[mxer147]

1999 Bonneville, I didn’t spray any water into the alternator so it could have some contamination. I also didn’t replace the belt since it didn’t appear that worn. I will spray the alternator down thoroughly with water and then air, and then try running it again. If the problem still exists, I probably will remove the alternator and battery to have it checked at auto parts store and also replace the belt. The alternator is original (265k) and battery probably now close to 10 years old. After replacing the water pump, upon initial startup it was running in the same condition it was yesterday upon initial startup. I can keep it running by keeping the rpm’s high but as soon as I let off the gas, it wants to die. The voltage gauge follows the rpm’s.

 

[fast 99]

Needs new belt. Antifreeze contamination cannot be removed. Been there done that. Even if you get the alt to work with an old belt it will be noisy.

Yes, a 10-year-old battery needs replacement.

 

[mxer147]

Ok, thank you for the advice and prompt response.

 

[Ricko1966]

Vehicle year unknown.
That is an old way of checking alternator output [works] and is not recommended on ECM controlled vehicles. Moment the cable is disconnected voltage spikes and could damage electronics.

Yes coolant can cause alternator failure. However, with engine off spraying the alt with water could clean it out internally. Should check voltage with a meter. Make sure the pully isn't slipping. Usually alternators will recover out but not always.

Wasn't telling him to disconnect battery cable was telling him to disconnect the alternator lead. Wasn't trying to check for output was trying to check for draw,he said his voltage is dropping to 6 or 9 volts if his battery is healthy,and charged it shouldn't pull down to 9 volts just running on battery.

 

[Bextreme04]

Hell, 11.5v on a lead acid battery is about 0% charge.

 

[fast 99]

Wasn't telling him to disconnect battery cable was telling him to disconnect the alternator lead. Wasn't trying to check for output was trying to check for draw,he said his voltage is dropping to 6 or 9 volts if his battery is healthy,and charged it shouldn't pull down to 9 volts just running on battery.

Agree with most of your diagnostics, they are right on. It was just a FYI on disconnecting power. Believe vehicle has 2-3 issues.

 

[Ricko1966]

Agree with most of your diagnostics, they are right on. It was just a FYI on disconnecting power. Believe vehicle has 2-3 issues.

I agree with yours most if not all the time. I think we went to the same school,rerings ,a valve and bearings and all kinds of stuff that was common that other people say don't do. I didn't take any offense,I explained because I thought maybe you didn't know what direction I was going.Unless he's got a bad battery he has to a serious draw to pull down as low if volts as he says,and I can only think of 2 draws that could be that big and we know it's not the starter. Thoughts? Lol after I wrote this I searched through other posts. I read post 4.Sounds like a battery,a belt and probably a vacuum leak created or wire pulled off while swapping water pumps.

 

[mxer147]

Made some time to replace the belt and disconnect the alternator cable. With cable disconnected, voltage stays around 9 and engine wants to die as it approaches idle rpm. Cable connected it stays near 14 volts if I stay above 1100 rpm. At idle it’s 9 and wants to die. I don’t see any disconnected wires. I also water flushed the alternator and waiting for it to dry out. Battery terminals and cables are clean.

 

[Ricko1966]

Sounds like you need a battery

 

[mxer147]

Changed out the battery with another from a different car, symptom remains the same. I’m thinking my crankshaft position sensor is failing? I replaced it several years ago when I experienced intermittent acceleration stalls during on ramp to highway. Removing the harmonic balancer was very tough, none of my air tools would work or the gigantic Milwaukee impact. Finally blocked a breaker bar and used the starter to break it loose. Wow, that’s always a scary moment knowing you could break the bolt or strip the head. Luckily it worked out and replaced the sensor solved the issue. It sure sucks when you have one issue which causes more issues, it’s easy to start throwing money at anything and everything. Hopefully, I can avoid that scenario.

 

[Raider L]

@mxer147,
Hey, if your battery has lasted for ten years I want one of those! Ha, ha. What brand is it?? I suppose though that it's becauise you haven't been driving it all the time and it's been in the car for ten years. Is that close?

 

[Ricko1966]

Check for vacuum leaks or wires you may have created,disconnected,created etc. while changing the waterpump. It would seem more likely that something you did inadvertently while changing the waterpump created a problem than the waterpump went out then the next day the crank position sensor failed. Besides it would usually throw a code p0335 I think. Might be 355 idk don't have a code book in front of me.