Where is this high pitch coming from?
03-06-2016, 09:23 AM
#1
Member
Thread Starter
Join Date: 02-04-2013
Location: Calgary
Posts: 47
Where is this high pitch coming from?
So I have been offline for a while, but recently I noticed a high pitch "whistle" coming from what I think is the engine, inside the cabin. The whistle can be heard at 2000+ RPM and can be heard while moving and stopped. Here is the issue the sound cannot be heard on outside the vehicle.
I have managed to rule out stereo or climate control as factors, as I have tested with these turned on as well as turned off the and the sound is independent of these systems.
No I have very sensitive ears, and to me it sounds like it is some sort of electrical whine, however when the engine is off there is no whine, so yet again another dead end.
With these points in mind I believe that it could be one of two things.
1. Leak some where in the intake manifold/airbox system
2. Leak in vacuum system
The issues I also have with both of these is that I have not had any diminished or abnormal engine issues ever, which to me would almost completely rule out the vacuum leak.
I thought it might be an engine bearing, but then I would expect to hear some unsusual engine noises as well as the stereotypical "wur" of a bad bearing. Also the sound does not appear to be anymore noticeable at 4000 RPM then at 2000 RPM.
2008 LT2 2.4 18XXXXX KM
So yeah thoughts?
I have managed to rule out stereo or climate control as factors, as I have tested with these turned on as well as turned off the and the sound is independent of these systems.
No I have very sensitive ears, and to me it sounds like it is some sort of electrical whine, however when the engine is off there is no whine, so yet again another dead end.
With these points in mind I believe that it could be one of two things.
1. Leak some where in the intake manifold/airbox system
2. Leak in vacuum system
The issues I also have with both of these is that I have not had any diminished or abnormal engine issues ever, which to me would almost completely rule out the vacuum leak.
I thought it might be an engine bearing, but then I would expect to hear some unsusual engine noises as well as the stereotypical "wur" of a bad bearing. Also the sound does not appear to be anymore noticeable at 4000 RPM then at 2000 RPM.
2008 LT2 2.4 18XXXXX KM
So yeah thoughts?
03-06-2016, 03:08 PM
#9
Technical Moderator
Join Date: 01-23-2009
Location: Fredericksburg, Virginia
Posts: 24,696
That doesn't mean it didn't crack or a nut come loose and/or burn up the gasket.
The other thing could be the rubber cap on the t-stat housing can crack and leak at high pressure. It turns to steam so no visible dripping.
The other thing could be the rubber cap on the t-stat housing can crack and leak at high pressure. It turns to steam so no visible dripping.
03-06-2016, 03:20 PM
#10
Member
Thread Starter
Join Date: 02-04-2013
Location: Calgary
Posts: 47
So how does one test for leaks in the flex pipe area?