[dklassen]

Here's a strange one. The other day my PM started making this super high pitched dog whistle sound after it starts. You can hear the sound kind of ramp up about 1 second after the motor fires up. It's not super loud but noticeable. My fist thought was either vacuum or electronic. Sounds more electronic to me, kind of like a power supply whistle from a bad cap or something. I can't seem to hear it from outside the van and it doesn't appear to be coming from the dash area. It almost sounds like it's emanating from the cargo area but I haven't been able to pin point the location.

Any thoughts?

 

[keeponvaning]

Mine has always done that in cold weather - not to worry.

 

[dklassen]

Interesting. Not too worried about it but the sound bugs the crap out of me.

 

[GapRunr]

Fuel pump?

 

[keeponvaning]

I think it’s the serp belt when cold myself it goes away very quickly

 

[dklassen]

This never goes away.

 

[KilWerBzz]

It could be the EVP system on the 3.6l, that would be the electric vacuum pump for brake booster support. When the vacuum is filling or emptying the booster, this could be causing the booster to cavitate through the fire wall and be heard in the van but not in the engine compartment. If this happens on startup disconnect the wire from the pump when cold and before startup if there is no noise then you found your problem. Reconnect the wire before driving.

 

[dklassen]

Thanks, I'll check it out. wow, how did you come up that hypothesis?

 

[KilWerBzz]

Thanks, I'll check it out. wow, how did you come up that hypothesis?

There are many check valves in the vacuum system and one could be stuck. The EVP is only a booster for the brakes you still have a standard vacuum on the 3.6l. So check them all.

 

[Winston]

We're not talking about 'alternator whine' are we? Infrequently we get a low volume alternator whine with no idea where it's coming from. This whine, however, is very easy to identify as it varies in pitch according to engine RPM.

 

[RDinNHandAZ]

It may be a sympathetic whine for the other alternator, or for the need to chew into a radiator hose.

 

[dklassen]

Dealer had a quick look today and it's definitely coming from the rear to mid point of the van. Not quite as noticeable today as a few days ago. Need to take it back at some point so they can dig in a little deeper. Was only there to pick up my wheel covers and have them put on.

 

[Julia]

Did you ever figure out what this was? I have the same problem in a promaster I just bought with 16k miles.

 

[RnR]

I had a high pitched sound coming from the factory cargo LED light relay in the pass side C pillar.
But only when the lights were on.
That's the only thing I can think that makes a sound like that, in that area of the van.

 

[Julia]

I tried turning them off and still heard it...

 

[Julia]

For anyone who is still interested in this, I took it to my dealer who thinks it's the fuel pump.

First, the mechanic said it was a normal promaster sound until I convinced them to take another look. You can hear it clearly from the back of the vehicle (maybe because there's no insulation to dampen the sound?) and from outside as well. It appears briefly when I start the ignition (but not the engine) and then disappears pretty quickly. When I turn on the engine, it's constant, high-pitched annoyingness.

They ordered a new fuel pump (luckily covered under warranty) which should be here by EOW. Hopefully, that should solve it.

 

[phil]

FWIW
If you remove the floor mat access cover between the seats, there is a metal fuel pump access cover held on by 3 screws, if that is removed the noise should be noticeable because that's the top of the fuel pump.

 

[Julia]

FWIW
If you remove the floor mat access cover between the seats, there is a metal fuel pump access cover held on by 3 screws, if that is removed the noise should be noticeable because that's the top of the fuel pump.

Oh huh. I'll check this out. Thanks

 

[Julia]

For anyone who is still interested in this, I took it to my dealer who thinks it's the fuel pump.

First, the mechanic said it was a normal promaster sound until I convinced them to take another look. It makes sense that it's the fuel pump as you can hear it clearly from the back of the vehicle (fuel pump is mounted right underneath there, I believe?) and from outside as well. It appears briefly when I start the ignition (but not the engine) and then disappears pretty quickly. When I turn on the engine, it's constant, high-pitched annoyingness.

They ordered a new fuel pump (luckily covered under warranty) which should be here by EOW. Hopefully, that should solve it.

Update: They replaced the fuel pump. The noise is quieter but definitely still there. They said that they think this is a common sound in promasters and that it would disappear after I add some insulation in the cargo area, but I'm still unsure about that as I've never heard it before in another promaster. Any thoughts?

 

[MsNomer]

The few recent posts are the first time we long-timers have seen. Definitely not normal.