I know this sounds farfetched, but, is the whistle coming from the heater control switches. Does the position of the switch make a difference. You said it is occurring only when it is cold weather. I had a GM car that the switch would whistle from a vacuum leak.

I am not sure if Dodge uses vacuum controls at at the heater selector switches. Also, check if any vacuum motors that control the ductwork could have a leaky diaphragm.

I wonder if the reason it happens in the cold winter is because you are using the defroster position or other position more so than in warmer weather.

I agree with using a garden hose or "stethoscope" device to pinpoint the location.

I used to use a flammable spray type choke cleaner like Gumout with the sprayer tube to locate many a vacuum leak at the engine. It worked very well because the engine would rev up as well as the vacuum noise decreasing.

Does feathering the throttle change it's sound?

 

Yes, the heater controls are vac operated- stillwhistles with controls to "off" heater control position makes no difference- whistled with ALL vac lines disconnected and manifold ports capped. Van only whistles under load, feathering the throttle changes noise. Much louder with doghouse off, the noise is from the engine bay.

 

I listened to the noise in your video. Wow, that would drive me nuts too! Did you try the garden hose thing while the cover was off?

Is there an AIR pump on this engine?

If so, does it pump into the converter? It is possible that the AIR pump hoses and/or connections are meeting increased resistance and air is finding a weak connection or made a hole in something and air is passing through it.

Have you ever pulled the spark plugs out to inspect the electrodes to see if any of them are different in color, condition, etc. This would indicate a lean/rich condition at that area. That could help in determining an area of the engine that could be problematic.

You didn't mention anything about how smooth the engine runs. From your video, it didn't sound like it had a miss or any power problems.

Any idea what difference a Magnum 5.2 has different from a 2002 regular 5.2? I am just thinking if I look at my 2002 5.2 setup to look for any ideas for you.

Is there a vacuum operated modulator on the trans? If so, check the hoses etc. You didn't mention anything about the trans acting strange, or shifting unusual, so I would probably rule this out.

The noise does sound like it is up topside by the volume I heard. Can you determine if the noise is from the left, center, or right side with the engine cover off?

I noticed you said that the vacuum is lower with the OD engaged. That would happen if the engine is under an increased load to maintain the same speed as with the OD disengaged. The throttle plates would be opened a little further to maintain speed. This in turn would decrease vacuum. I would think that the OD would disengage if there is an increased load.

 

All Magnum engines do not have Air Pump.

 

Ah, every 3.9L, 5.2L and 5.9L made after 1994 became a Magnum 3.9L, Magnum 5.2L, and Magnum 5.9L. Ram Van engines prior to 1994 were non-Magnum with TB and carbs.

 

Thanks for yor input! No air pump or EGR. I did change the plugs - looked pretty normal with no real variations between plugs. Engine runs fairly smooth (slight lope @ idle). No modulator for tranny ('puter controlled) tranny shifts like it should. The lower vac reading in O.D. is understandable , but a loss of 4MPG in O.D. ? Havn't done the hose to the ear yet ( explain to the nice RCMP officer what that man is doing down between the seats with a stethescope) I talked to another mechanic today- his first response was "yep, belly pan leak,all the symptoms fit". Looked for another keg at the wrecker's today, no luck. When I find one, I'll take my time on the mods before I pull the old one.

 

No luck finding another keg yet, but I've got the word out. Had a friend go for a ride with the garden hose to the ear, he wasn't able to pinpoint the source of the whistle. He agrees it's not a bearing, but it is freakin' LOUD. Somebody has to have had the same problem and has the correct answer.

 

I have a 2003 Dodge Ram Van 1500 and at times when it is cold it has the same whistle that you describe 36 ******. My mechanic told me it could be the air blower making the whistle, just because the air is so cold. He had seen this problem on other vehicles, really nothing that you can do to stop it from what I understand. Hope this helps you... the whistling is annoying....

 

Air blower? is this the blower for the HVAC system? If so, then the outside recirc baffle-door would need to be adjusted to reduce or eliminate the awful whistle.

 

No it is not the Heating/Air Conditioning Fan, it is the air blower for the engine....