Tonight was pretty cold and wet, very dewy in the air. Started the car and put the heater on full because it was steamy like a cold sauna (wtf?)

Anyway, put the air con on to de-humidify the air and as soon as i did that there was a screeching sound from engine bay so i figured it would be the belt running the AC compressor. Then the fan dropped suddenly to very low speed and lights went dim. I drove it gently all the way home and idled it for a bit on the driveway. When i let it idle and then give it some gas in neutral, the lights go from dim to bright. Is my alternator and/or battery in need of replacing?

check belts.

I would be looking at the Compressor clutch,could have thrown or smoked the belt already due to it being siezed,i would check that first,hence the screech and lights dimming from the extra load from the possibly siezing compressor?

If not,then have the Battery and charging system checked by a sparky

Steve

it sounds like your AC cut in and the belt wasn't tight enough to drive it and just skipped a bit.

Replace the belt and see what happens.

it sounds like your AC cut in and the belt wasn't tight enough to drive it and just skipped a bit.

Replace the belt and see what happens.


possibly,but how does one explain the extra load on the engine at the same time?,im still thinking clutch

I pretty much agree with Steevo - at least initially you should check Air-Con clutch, cos that's where problem seemed to start (plus I have horrible memories of a compressor seizing in a TN, and having to continue driving from Shepparton to north of Dubbo in 40degress ++ at Xmas time, with no prospect of getting air-con fixed).

If the air-con clutch and compressor seems to operate OK, and there is no damage to the drive belt, then obviously check tension of belt is within normal limits. While you are at it, listen for bearing noise etc from alternator.

The screeching noise suggests belt to me, the poor level of charging (dim lights etc) could also be down to a damaged/loose drive belt not driving alternator properly.

I'd certainly be investigating the belt before considering an expensive option like replacing the alternator. If you can access the PDF workshop manuals in Tech Torque thread, check in them for a trouble-shoot of this problem - the solutions are usually ordered in priority of common/simple problems first, and progressing thru other less-likely possibilities.

I pretty much agree with Steevo - at least initially you should check Air-Con clutch, cos that's where problem seemed to start (plus I have horrible memories of a compressor seizing in a TN, and having to continue driving from Shepparton to north of Dubbo in 40degress ++ at Xmas time, with no prospect of getting air-con fixed).

If the air-con clutch and compressor seems to operate OK, and there is no damage to the drive belt, then obviously check tension of belt is within normal limits. While you are at it, listen for bearing noise etc from alternator.

The screeching noise suggests belt to me, the poor level of charging (dim lights etc) could also be down to a damaged/loose drive belt not driving alternator properly.

I'd certainly be investigating the belt before considering an expensive option like replacing the alternator. If you can access the PDF workshop manuals in Tech Torque thread, check in them for a trouble-shoot of this problem - the solutions are usually ordered in priority of common/simple problems first, and progressing thru other less-likely possibilities.

Too true,I may have jumped the gun on the belt bit,havent really looked if these engines run a seperate belt on the charge system,and another for water pump and ac comp etc,if not belt could well be slipping and not turning the alt etc

I had that exact problem in another car........ it was a loose belt slipping

cheers guys, i just remembered that when i first got the car the belt snapped clean off and was fixed and replaced by the holden dealer i bought it from 3 hours earlier. Bloody greasemonkeys probably didnt put enough tension on the belt.

cheers guys, i just remembered that when i first got the car the belt snapped clean off and was fixed and replaced by the holden dealer i bought it from 3 hours earlier. Bloody greasemonkeys probably didnt put enough tension on the belt.

Maybe so, but new belts "bed in" a little bit, and belts may stretch slightly as they age, etc etc. The workshop manuals often state measurements for "new" belts and "worn" belts, to account for this. The manuals for the Magna suggest straight "run" of belt between two pulleys, and you feel/measure how much the belt can be deflected by pressing on it - a loose belt has more "give".

Just be guided by what the manuals suggest, as too much tension can put excessive force on alternator bearings, and cause them to fail. If the belt seems too loose, check the inner "grip" sections of the belt for the full length, to ensure no patches of wear have occurred. (When an air-con compressor seized on my old TN, it wore completely through the belt, lots of friction and belt was gone in seconds - while doing 100kmh approaching Shep).