The alternator in my '04 Lumina SS is its Achilles' heel. It lasts a few years before it starts to overcharge the battery, after which the only practical remedy is to replace it.

While I cannot be sure of the cause for this, I have always noticed that a tremendous amount of caked-on dirt and dust accumulate in the windings over time. In order to extend the life of the alternator I would like to clean it out as much as possible.

I don't mind taking the alternator out of the engine bay to do this. I'm a little nervous about disassembling it though since I tried it once upon a time and ended up damaging it.

Obviously water and alternators don't really mix well. One idea that springs to mind is to hit it with brake cleaner, though I'm concerned that doing so may compromise the in-built voltage regulator.

So, questions:

  • What options do I have?
  • What precautions should I take?
  • And are there any recommendations or tried-and-tested methods that I should follow?
  • 2
    Chevy Lumina SS a.k.a Pontiac GTO (US), Holden Monaro (Australia), Vauxhall Monaro (UK)
    – Zaid
    May 5, 2014 at 14:53
  • Just to clarify, I'm interested in how to clean an alternator, and not the possible causes for the alternator overcharging. That kind of stuff is better discussed in chat.
    – Zaid
    May 5, 2014 at 14:54
  • 2
    While I haven't tried it, I would assume the alternator is cleanable with a high pressure hose. You could douse it with engine cleaner and hit it with some water, should do the trick. Components under the hood are (in most cases) made to withstand water. It's not like it never rains (unless you live in the desert or something). I'm not putting this as an answer, as other people may have other thoughts. This is just a "knee-jerk" comment, so don't take it as gospel, but I bet you'd have no issues. May 5, 2014 at 15:06
  • I'd also guess that water probably whouldn't hurt it (unless it already had a problem started anyways). Even then, I'd be hesitant to use high pressure for fear of working water deep in where there's a problem already brewing. On a side note, I do know that oil is definitely bad for them... :-) All that said, I doubt dirt is the root cause. May 5, 2014 at 19:10
  • My first inclination would be to blow it out with an air hose if you have access to one, it sounds like you're dealing with dust and dirt and not so much oil or other sticky stuff. If you find that it doesn't blow out, then engine degreaser followed by flushing with a hose (as best you can avoid the bearings). Engine compartments get wet or at least damp in most climates. Then get it warm to dry it out before anything has a chance to rust.
    – dlu
    Jul 6, 2016 at 8:04

3 Answers 3


I'm not even close to being a mechanic but after doing web research for myself, I found out most if not all brake cleaners have chlorides in them, therefore internally can cause rust and then, well you know the rest.

I decided to go to Bursons Auto and ask for a circuit board spray. $22 a can. I sprayed my alternator this afternoon all over and in it and watched the black oily crap drip from the underneath. Apparently, any spray remaining anywhere will evaporate away.

Ill keep you posted.

I don't want to piss off any mechanics out they're either. I'm not a mechanic and am definitely learning the basics up so only try my options at your own risk.

  • 1
    Please don't shout...
    – Nick C
    Mar 1, 2016 at 10:02
  • By shout, you mean CAPITALS? I really didn't think people would be so touchy about such things. I shall speak softer from now on
    – Ryne
    Mar 3, 2016 at 7:28
  • No dramas and noted Nick C
    – Ryne
    Mar 5, 2016 at 5:46
  • My only worry about this method is that it may push grease out of the alternator bearings. Jul 26, 2016 at 8:42

My first thought would be to find out why the alternators are failing. Make sure you have good connections at the battery, the alternator and any ground cables. If you frequently let the battery run low with a power robbing device like a large stereo, power inverter and such you may be overworking the alternator recharging the battery. Another possibility is that the alternators you are getting are poor quality. Are they reconditioned (only the broken parts are replaced) rebuilt ( the broken parts along with any wear items are replaced) or remanufactured ( anything that is worn or could wear is replaced). If you decide to clean it I would use nothing but compressed air. Any solvent or water sprayed in the alternator has a chance of getting into the bearings ruining them. I would blow some air in from both sides. Be prepared for some really nasty dust from the brushes.

  • 1
    I hope you realize the OP is located in Doha, Qatar. Sandstorms and such are very common there. And when I say "sand", it's more like glass powder. Even with a minimal amount of lubricant exposed, this stuff cakes up on it. Then it becomes like sand paper and will destroy moving parts ... Yes, my comment above does not reflect location, either. May 6, 2014 at 12:06

You could try using Isopropyl alcohol. It is the main component in allot of electronics cleaners since it evaporates quickly and leaves no residue. Quoting wikipedia:

Isopropyl alcohol dissolves a wide range of non-polar compounds. It also evaporates quickly, leaves nearly zero oil traces, compared to ethanol, and is relatively non-toxic, compared to alternative solvents. Thus, it is used widely as a solvent and as a cleaning fluid, especially for dissolving oils. Together with ethanol, n-butanol, and methanol, it belongs to the group of alcohol solvents, about 6.4 million tonnes of which were utilized worldwide in 2011.[13]

Examples of this application include cleaning electronic devices such as contact pins (like those on ROM cartridges), magnetic tape and disk heads (such as those in audio and video tape recorders and floppy disk drives), the lenses of lasers in optical disc drives (e.g., CD, DVD) and removing thermal paste from heatsinks and IC packages (such as CPUs[14]). Isopropyl alcohol is used in keyboard, LCD and laptop cleaning, is sold commercially as a whiteboard cleaner, and is a strong but safer alternative to common household cleaning products.[which?] It is commonly used to clean prepared optical fibers just before splicing. It is used to clean LCD and glass computer monitor screens (at some risk to the anti-reflection coating on some screens[citation needed]), and used to give second-hand or worn non-vinyl phonograph records newer-looking sheen. It is effective at removing Hot-Melt Adhesive from a large variety of surfaces. It is effective at removing residual glue from some sticky labels although some other adhesives used on tapes and paper labels are resistant to it. It can also be used to remove stains[clarification needed] from most fabrics, wood, cotton, etc. In addition, it can also be used to clean paint or other oil-based products so that they may be reused, commonly known as "repainting." It is used as a wetting agent in the fountain solution used in lithographic printing, and often used as a solvent for French polishing shellac used in cabinet making.

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