Recent Topics
AMSOIL Euro Classic 5W-40 (EFM)
by The Critic
07/15/18 06:27 PM
Occasional battery dummy light
by dja4260
07/15/18 05:59 PM
Weird experience with old separating brake grease
by d00df00d
07/15/18 05:54 PM
Ceiling Finish Help
by coopns
07/15/18 05:10 PM
Thunderbird to Outlook Converters??
by doitmyself
07/15/18 04:41 PM
Blaines does it again
by Nitronoise
07/15/18 04:40 PM
BMW E34/M60 Water Pump Replacement
by kschachn
07/15/18 03:30 PM
Okra: how do you make it and like it?
by car51
07/15/18 03:28 PM
2005 Sienna trans issue
by i6pwr
07/15/18 01:46 PM
How is your MLB baseball team doing
by car51
07/15/18 01:02 PM
(8) WIX 57356 + (4) Fram Ultra XG7317
by redhat
07/15/18 12:51 PM
Royal Purple oil filter
by 4WD
07/15/18 12:43 PM
Elon Musk calls Thai Rescue Diver a "Pedo Guy"
by DoubleWasp
07/15/18 12:27 PM
Cam Cover Pics...'96 Mazda
by splinter
07/15/18 12:24 PM
1994 Civic LX 1.6L Drive axle boot replacement
by Gito
07/15/18 12:04 PM
F 11 and other magic Spray~On Top Coats?
by HammerDown
07/15/18 11:43 AM
Fuel Line
by Warstud
07/15/18 11:00 AM
Baldwin P9600 Cartridge
by Bighorn2500
07/15/18 10:25 AM
The meaning of POP
by buster
07/15/18 09:02 AM
Malta Goya
by car51
07/15/18 08:49 AM
Newest Members
ShadowSama, Heidi1975, Dieselman24, mikeyh, tmpokc
65478 Registered Users
Who's Online
78 registered (69Torino, 08z06, alcyon, Al, ak1059, 11 invisible), 1686 Guests and 32 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
65478 Members
67 Forums
287071 Topics
4790097 Posts

Max Online: 3590 @ 01/24/17 08:07 PM
Donate to BITOG
Topic Options
#4808768 - 07/09/18 02:44 AM Help! Strange charging system symptoms. Bad alt.?
Happy Birthday 19jacobob93 Offline

Registered: 02/12/14
Posts: 701
Loc: Gold Coast, QL, Australia
Symptom: washed engine - now alternator intermittently over charging, lights go bright and engine labours every 20secs or so when battery light comes on. Engine power loss under load.

I gave my engine bay a quick rinse down a couple of weeks ago, I've done this dozens of times before without an issue but this time I was heading away and the car wouldn't be started for another 5 days = cold sitting water.

When I came back my battery light was on and the engine sounded slightly labored like the alternator was working over time and I figured it will just be topping the battery up after sitting...
I took it for a drive and the light would go on and off but got less frequent, but now the engine would lose almost all power when under load like setting off from the lights and would take a few seconds to pick back up, which I had to be light on the throttle and fether the revs up. Revved out perfectly fine in neutral/park though.

The battery now showed red or 'replace' so I took it back under warranty but the multimeter test showed it to be fine.
They swapped it anyway and I just fit it but the car still intermittently shows the battery light (every 10-30secs) and when it comes on the engine drops revs a bit like it's laboring and the headlights and dash cluster lights brighten significantly, then back to normal again when the battery light goes off...

Could this random overcharging be a sign of a bad alternator? My guess is water could have sat in it for a few days and caused damage
Car: 2000 Ford Falcon AU2 - 4.0L SOHC I6 @325,000km
Oil: Castrol GTX UltraClean 15W40 + Ryco Z9 filter
Fuel: 95 octane E10

#4808862 - 07/09/18 07:56 AM Re: Help! Strange charging system symptoms. Bad alt.? [Re: 19jacobob93]
spackard Offline

Registered: 03/24/11
Posts: 1750
Loc: CA
It sounds like the regulator to me.

#4809184 - 07/09/18 12:36 PM Re: Help! Strange charging system symptoms. Bad alt.? [Re: 19jacobob93]
JMJNet Offline

Registered: 09/06/07
Posts: 950
Loc: TX, USA
In most cases the voltage regulator is part of the alternator.
So, YES, the alternator is bad and needs to be rebuilt.
Depending on the model/type of alternator, a good rebuilder can test it and see if it is just the regulator that needs replacement.
  • 2017 Toyota Sienna
  • 1995 GMC Suburban 6.5L Turbo Diesel

#4809484 - 07/09/18 06:08 PM Re: Help! Strange charging system symptoms. Bad alt.? [Re: 19jacobob93]
Colt45ws Offline

Registered: 08/15/06
Posts: 9680
Loc: Central Washington
You might pull the electrical connector off the regulator and make sure there is no water in there, no corrosion or something messing up the works. Since it was sitting for 5 days, it may have possibly devloped corrosion in the connector if water was forced into it. Might even be worth de-pinning the connector and just checking to make sure.
This is why I dont wash engines ever. Too many electrical items and connectors that can get water trapped in them, more so if you are using a pressure washer, forcing the water into places it shouldnt be.

Edited by Colt45ws (07/09/18 06:11 PM)
2002 Ford Crown Vic PI 207k, Ex-Kootenai County, ID Unit #42
Down for engine swap
2003 Ford Crown Vic PI 75k
Castrol EDGE HM 5W30, Fram XG2