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Sun 17 Jun, 2012 12:10 pm
I have a '95 Mazda 626 sedan, with 4-cylinder engine and an automatic transmission, that is in a good overall state of repair, and runs and drives well. In the recent past couple of months, I've noted that when the car is initially started in the morning, that more frequently than not - there is a very high-pitched screech (from under the hood of course). This sound seems to last until the point when the transmission is engaged and the car starts to move. I can't seem to figure out the source of this noise, and since we've accounted for the family cat and not noted any other extraneous wildlife under the hood, I'm trying to isolate this sound, now that we've eliminated at least a couple of "the usual suspects".
On the assumption that the noise originated from one of the three serpentine drive belts, I lightly applied some belt conditioner (WD-40) to both the belts and the pulleys. None of this seemed to have any effect whatsoever. Given that this is a front-wheel drive vehicle, with a transverse engine, and all the components under the hood are pretty well jammed in the available space, I've not been able to audibly geo-locate the source of the noise, just by listening, since the noise is intermittent (doesn't occur every time, but most times) - but it's clearly associated with starting the engine and the engine running initially. Likewise, there doesn't seem to be any noticeable, detrimental mechanical effects from this noise and it does not sound to be an engine-related problem either. There's clearly some significance to the fact that the noise totally disappears, when the car is placed "in gear" - but beyond that, I'm clueless. Any help?
@CDobyns,
How many miles are on the car? Perhaps you have 200k miles or more? When was the water pump changed?
Are the belts glazed or cracked?
If the belts are in good shape and properly tensioned, I'm guessing here but could it be water pump bearings?
Rocky? what do you think?
@Ragman,
Sorry. I didn't mean to volunteer 'ya, Rocky.
@Ragman,
Okay, some good quick conjecture of potential culprits - but on the water pump theory, I think we're going to come up "dry".
The vehicle has under 130K miles, and coincidentally the water pump (and timing belt) were changed out just a couple of months ago. The drive belts themselves all seem to be in good condition (flexibility, pulley track grooves, etc.). This was some good diagnostic speculation, but I'm nearly certain that there's some kind of "nexus" to the initial sound, and the fact that the sound completely disappears when the vehicle is placed "in gear". Any other?
Have you tried someone else starting the car while you stand in front of the car (and to either side) with the hood up, listening? See if you can fine down the location a bit? I'd have thought belts would be the most obvious point too.
The usual suspect is slipping belt(s). Sometimes low power steering fluid.
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