Whenever I turn on my rear defroster or heater in general a weird thing occurs. It happens randomly but as I begin to accelerate I hear a screeching/squaky noise coming from the engine bay. It only lasts for about half a second- second and then goes away. This only happens when I have the rear defroster on, or I have my heat on (or both). I have no idea what it could be but it only occurs on the onset of acceleration then goes away. Any ideas?

 

Probably a loose or worn fan belt. Check it again with the hood open to be sure.

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92 Camaro RS, LO3, 5-spd, T-tops

Performance:
K&N Open Air Filter, Edelbrock performer TBI intake, Fastchip Prom, Timing +4 degrees, Centerforce clutch, Xact 8mm wires, SLP 1 3/4" Headers (coated), Flowmaster Catback Exhaust, Richmond 3:42 gears, Torsen HD Posi
Sights & Sounds:
Alpine 8030 Alarm System, Valentine One Radar Detector (How did I ever drive without one?), Pioneer DEH 7450 Head Unit w/6-pack CD changer, Pioneer DEQ 7600 Sound Processor, 2 Kenwood KAC-846 Amps powering 2 12" Pro Red subs, 2 Pioneer 6x9 and 2 MTX 4x6 speakers. Z28 grille w/aftermarket lights, MacEwen whiteface gauges
NEXT UP: TBI & Suspension mods

 

I second the belt idea.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R
and 2 POS commuters...

R.I.P. #3
"He can see air"

 

Judging by your description this sounds like it's probably not the problem, but I thought I'd mention it just in case:

When the fan/blower motor starts to wear out, they will make an obnoxious noise intermittently (usually for a few seconds at startup of a higher speed on the fan). This has nothing to do with the rear defroster except for the lower current (amperage) that would be available to the motor. The fans on these cars run all the time but sometimes only make the noise while at a higher speed setting.

Like I said, it's a longshot, but a possiblity. It's more likely that it is the alternator belt (now that I re-read the acceleration part of your post). Just tighten the belt and use some belt dressing compound. Either way, it's a cheap easy fix.

Clem

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Clem
SCCA TransAm Series Race Mechanic/CrewChief
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1983 Z28 with LG4, 5 speed, and (unfortunately) T-tops
1983 Z28, NO T-tops, (unfortunately) Auto Transmission (hopefully not for long)

[This message has been edited by clemsparks (edited November 06, 2001).]

 

Thanks for the suggestions, I know it isn't the belts since I just replaced them last month and it didn't solve the problem. I really think it could be the fan motor as you said, I'm going to check that out later in the week when I have some time. Thanks alot, also I have another question. The amperage on my readout seems to fluctuate greatly, if I have a lot of things on (defroster, heater, lights) it really goes low and my right/left turn signal tend to lag. Any suggestions there?