Replacing Alternator


Asked by Mar 09, 2013 at 07:26 AM about the 2003 Chevrolet Venture LT Entertainer

Question type: Maintenance & Repair

I can't find an exact match for my broken alternator GM P/N : 10448038, 14V, 140Amps (Valeo). I'm
considering to replace it with a 12V, 120Amps. Will this work without worrying about anything?

32 Answers

You will be fine with that. A 120 amp is a moderately high out put alternator and dropping only 20 amps should operate everything just fine. For example, an ambulance with all those high draw devices usually has about a 300 amp, and a mid size or compact car use about a 90 to 120. As for voltage, an alternator RATED at 12 volts will actually produce about 13.5V. BUT now if you have a super duper stereo amp, or any aftermarket high draw device, then all bets are off on what I said

2 people found this helpful.

PS only one thing: driving habits. If you normally only go short distances, say 2, 3 miles and shut you car off, go in grocery store or whatever, start again drive 1 mile home, and do that time and time again, then also all bets are off.

1 people found this helpful.

Great! I don't have any additional high draw device other than the occasional LCD TV and DVD player that my kids use for karaoke during out of town trips. Hahaha. I was just worried about the computer going cocoo with les than 20amps. Can I push my luck and ask you a question about Throttle Body and Mass Airflow Sensor?


You will be good. shows 105 amp and 120 amp for your application, no 140 amp alternators. Prices range from $130 to $245 and a couple don't have a core charge.

2 people found this helpful.

The alternator puts out what the regulator tells it to, at any given time depending on draw, the 120 is maximum for when there are a lot of things demanding power, like EVERYTHING on . lights, wipers, heater fan, rear window defroster, and so on...then you decide to put window up and push cigarette lighter and...

1 people found this helpful.

Thanks Tenspeed!

Good morning TS..and Sid go ahead with your other question...


Morning people!


It's a beautiful morning indeed. Thanks for the help guys!


If it fits properly meaning pulley position in relation to belt alignment. If it were mine I would take it to a electric motor repair shop, one that does alternators, by doing so you can put the same on e back in and eliminate a lot of potential problems associated with any type of cobbling.


Sound advise mrmoony, I did take it to a shop unfortunately we don't have the broken spare part here in the Philippines. The Auto electrician told me that the thing mounted on the butt of the alternator is the one broken (Is it the regulator? I'm not sure). So I searched the net and found that the cost of the "regulator" (as I think it is) is almost the same with the whole alternator. Hmmmm, should I just replace the "regulator", taking it off from my replacement part to the old one? Does this make sense?

I don't think you can change the regulator. it's integrated in with the alternator, with the rectifier diode transforming the AC the alt. makes to the DC your car consumes. That's why it's called an 'alternator', it reverses poles back and forth for better efficiency in producing power, but then of course must be 'rectified' to DC. And I agree mrmooney makes a great deal of sense there. It MUST have the sheaves aligned

2 people found this helpful.

Very nice explanation on the AC-alternator-DC, now I know. Coming back to your P.S. on driving habits, yes I do make short trips similar to what you described. Now will this be a problem? Will idling the engine 10mins before I shut it off help charge the battery to prevent re-start failures or draining the battery? Before my alternator broke my battery died every month. So I purchased a new battery - problem solved. Then one night as I was driving home (a 3-hour trip) the instrument panel went cocoo, turning on and off. The next day i brought it to my mechanic. This is when he said that my alternator is broken.

As for your question: yes. idling for w while will help keep the battery up. I have heard conflicting information/opinions about how long it take to re charge a battery after starting, Some say 10 miles or 15 minutes, others say 2 minutes. I am somewhere in the middle. But it happens, like a neighbor of mine; it is about 3/4 mile to a little 'general' store and she drives there about every other day, Start, drive 2 minutes, shut off, start, 2 minutes home. Nowhere else. I have had to jump start her several times, she asked me what it would cost to "fix" it, and I told her there is nothing to fix except DRIVE it. So for one, she leaves it running while in store, (we live in one of the last places on planet Earth where a body can do that..) and drives with O/D off to get a few more rev's up, and goes the "long way" home, a 10 minute drive. I have not had to give her a jump start since....NOW... I really don't understand how or why the alternator being "broken" will effect your instrument cluster. Do you have a multi~meter? Check voltage at battery with both engine running and not, running, going waaaay back up to the top here, should show 12.5 to 14V. Off, 12 to 13 or so.

2 people found this helpful.

So I'll be back to old-school habit, start the car, idle for 2mins, go wherever, go back to my garage, idle for 2mins, then shut-off engine. My mechanic showed me the multi-meter when the engine was running. It was not charging. Then he took out the alternator, tested the regulator thingy, did not flick the meter, then concluded it was broken. Thanks for the story master DavidH25 !

Afterthought. Idle is not a real good way to re charge battery, after I re read your post. Sure, it will, but at 2500 rpm it will happen much faster..exponentially. A 900 rpm idle will NOT charge at half the rate of 1800 rpm. Only about 20%. 2000rpm will charge 4X faster than 1000rpm. Follow?

1 people found this helpful.

We were typing at the same time


Yes David I follow. This is getting better...Now I have a reason to drive around before going home...hahaha!

oooooh... that's what I need, excuses, Opps I mean reasons


Hey Sid, since you park in a garage can you hook up a battery tender? It provides a trickle charge to keep your battery topped off.


Here's a ebay BIN as an example - Battery-Float-charger-12v-Trickle-Tender-Loving-Care-for-your-car- /130863419127? pt=Motors_Automotive_Tools&hash=item1e78114ef7&vxp=mtr


Another great idea! Eh...what's a battery tender? Can you send me some item number fro eBay or Amazon?


I got it TS! This is a cool gadget, thank you very much! Now I can go home late without actually driving around, but still say "I needed to drive around honey to charge the battery". Hahaha! You're the best!

A trickle charger that puts out a very small amperage to keep the battery up. Wal Mart. kMart. autoZone. No need to pay shipping et al


I saw a lot on eBay, what specs should I go for? Hey, will this charge a dead battery as well?

Ok. First, if it is not a deep cycle battery and has been dead a long time, no charger will charge it. But the trickle charger usually has a ''trickle, like 1 amp or less, and a 5 or 10 amp setting, so, yes. It will. eventually

1 people found this helpful.

Nice, so I should go for something that has a high amp setting also?

You do NOT need to spend a lot. It's a simple 120 volt to 12 volt transformer/rectifier for 120V ac to 12V DC

1 people found this helpful.

Yeah I saw one at $13 free shipping

No. Not really. They get expensive for high amperage chargers and usually only professional mechanics need those for a quick charge. Not something you need around the house for ordinary use

1 people found this helpful.

Got it masters, thanks a ton!

I live in Canada, and bought a charger for $70.00 CDN at Napa.I also am in the midst of changing my alt and battery on my 2002 Montana. I could not buy the parts in Canada, but they are available in the USA. Both bearings, brushes and regulator. The brushes and regulator are together. Only 3 bolts hold it in place. Good luck. I put a rebuilt on, and had to replace it, as it was no good.

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