Whistle from engine bay after water pump.

[Ken Rolls]

Installed a new water pump (which is also leaking) and now when it's cold there is a vacuum leak whistling sound. Once engine warms up it goes away. Racking my brain looking for it. Everything looks fine so it's a head-scratcher. Almost sounds like the old radios that whined through the speakers if not grounded right. Ever hear of a water pump whistling?? I'm stumped. Thanks in advance

 

[MassHoe04]

Whistling on start-up and disappearing after warm-up can sometimes be intake gasket. Once the engine warms up, things can expand and seal up the leak.

On the water pump: Both mating surfaces have to be as clean and smooth as possible. Plastic scrapers and 3M (or similar) scrubby pads only to clean the surfaces. If there are pits in the metal, that might prevent a good seal, you can swipe RTV with your finger. Just what is needed to fill deep pits, not making a gasket out of it.

Also might try a Fel-Pro water pump gasket. They go onto clean smooth surface, dry, with no RTV at all. They have a built-in bead of silicone on the gasket and I had great experience using one on my Jeep. Not a drop on the first try.

 

[Ken Rolls]

Whistling on start-up and disappearing after warm-up can sometimes be intake gasket. Once the engine warms up, things can expand and seal up the leak.

On the water pump: Both mating surfaces have to be as clean and smooth as possible. Plastic scrapers and 3M (or similar) scrubby pads only to clean the surfaces. If there are pits in the metal, that might prevent a good seal, you can swipe RTV with your finger. Just what is needed to fill deep pits, not making a gasket out of it.

Also might try a Fel-Pro water pump gasket. They go onto clean smooth surface, dry, with no RTV at all. They have a built-in bead of silicone on the gasket and I had great experience using one on my Jeep. Not a drop on the first try.

Thanks. The leak is actually from the pipe on top of the pump. The chrome looking one. Same spot the old one leaked from. Intake gaskets were done 2 years ago. No cel or stumbling. Runs great.

 

[OR VietVet]

Either poor quality pump instead of a Genuine GM or a problem with install about leak.

I would bet that the noise is a belt. Take it off and start when cold and see if the noise is there.

 

[MassHoe04]

I have had vacuum leaks on the intakes without CEL coming on. The computer compensates for the extra air coming in by increasing the flow of fuel from the injectors.
One ran extremely rich had no balls going up hills. The other had crazy run-away idle like I had the gas pedal floored. Neither had any CEL.

Just curious... What is the idle RPM right after the cold start?

Certainly could be belt as suggested. @OR VietVet is one of our best in diagnostics.

 

[RAMurphy]

Without hearing the noise, I would guess belt first as @OR VietVet suggested. Very simple to check - he provided the troubleshooting procedure. I also agree you can have that vacuum leak without a code. You would need to do a diagnostic run with a scanner and then you should be able to determine whether your computer is compensating for that vacuum leak. As far as the leak are you sure it is not coming from the hose connection. I have a hard time believing that the old pump and the new pump were leaking from the same location. Although, I guess it could happen.

 

[MassHoe04]

Is it a new hose and clamp on there?
Gates or GM would be best choice for replacement.

 

[Ken Rolls]

Is it a new hose and clamp on there?
Gates or GM would be best choice for replacement.

Its that pressed in tube at the top leaking

 

[Fless]

Its that pressed in tube at the top leaking

How about a pic or two for all of us?

 

[tungsten]

The whistle sound could the tensioner pulley bearing.I have one that squeals.