Another quick question. Temps here have been sub 20's.

Start up has a 'loud' whine from under the hood. As the car warms up, approx. 5 minutes, it quiets down.

Last night I observed the digital battery voltage readout: Cold start 15.1
A few minutes later 14.9; after 20 minutes of driving 14.7; and when I got hope 40 minutes later 14.3,

Does this sound normal? Could the whine be an alternator ready to go out?

In normal weather there isn't the whine, but the air pump IS fairly loud.

Thoughts & direction most appreciated...

 

Your battery at 15.1 means that it was a little low when you first started the car but the volts dropping the whole time your driving the car means your alternator is working properly ..The whine your hearing is probably bearings being cold, my airpump does this when the temp gets real low like we have had lately, but stops within a few minites.If it would keep whining after a few minites then I would worry...WW

 

If i´m not mistaking the digital readout shows the charging voltage when running.

See what happens when you start the car and start turning on some power users like rear window heater, if it stays in the +14 volt range, there is nothing wrong.

If you turn off the engine (after 10-15 minute drive), read it again.

It will most likely be around 12.5 volt, wich is OK.

If it´s under 12 volt, you might be in the market for a new battery.

My air pump is also loud, it´s their way of letting know they are there too.

I think they feel lonely sitting all the way up there...

 

I dont know about you guys but my alternator makes a barely noticeable whining noise even after it warms up... It works fine, but when the hood is up it sounds like a supercharger (except not as loud)...

Any thoughts? Any way to stop the noise?

 

You should have heard my S-10 when it was sub-zero. The noise was horrible until it warmed up.

 

Id open the hood n see where the noise is coming from.

 

sounds like the power steering pump, fluid is heavier when it's that cold. Wouldn't worry about it but check your level.

 

Been experiencing rough cold starts past week. it was 17 this morning. had trouble turning over.

 

I have a `02 Jeep liberty that whines loudly at startup when its cold outside. After a minute or two it goes away. Found out that its the power steering pump. Its not bad, its just the way it is. A lot of Jeeps do this. When the weather is warmer--no noise--.

 

Mine has done that twice. It was the alternator going out both times. The second time was just today. Heading out to pull it off now.

 

first remove serp belt, start engine, see if whining stops...serp belts get noisey when 'mature' (underside 'cracking' is a clue, not proof), low or old p/s steering my second guess, tensioner pulley bearings my next guess, then the others.

 

'synthetic' oil in crankcase has pretty much ended that prob 'out here'...'good' battery, 'up' on charge is still mandatory...weak/old battery cranks slow, simply 'too many' short trips without sufficient recharge time between can lower battery's enthusiasm.

 

Sounds like the power steering pump.

 

The 'volt gauge' in our cars is barely a good enough indicator. I wouldn't trust that even over a cheap multimeter. Get your self a multimeter and test the battery terminals with engine off, then with engine on. Avg. of 12.9~13 is okay with engine off, 13.6~14+ with engine on. Of course YMMV, but you get the drift.

As for the alternator, see below. On that note, the air pump is such a waste of space. Anyway, for a dump fix you can try squirting some WD40 in it through the holes and see what happens. Other than that, you can either spring for a new old stock airpump (I'd say don't), get a junk yard part, or do what I did... get the air pump eliminator kit.

Not cool to hijack OP's thread, but it's okay, I'm not the forum police. If it's indeed the alternator, you can either live with it until it dies or take it off and find a local alternator rebuild guy and let him repack the bearings (or fix whatever's worn out) Other than that, no way to quiet it, it's not like there's places to squirt grease. My advice if you guys ever get new/rebuilt alternators get it here:

http://www.alternatorparts.com./CS-1...cial_offer.htm

I tossed my crappy CS130 with a robust CS144 and never looked back. Lasted me a good 5+ years until I had it rebuilt by a local guy. No doubt it'll be good enough for another few.

Best simple response! Guys, try look/hear for where the problem is first. Then come back and report.

All good areas to check. However to the OP, my bet's on the alternator or the air pump... you can only tell by putting your ear close to each one and find out. Be careful though!

Good luck.