Hi all. In my 1987 4Runner with a 22RE I recently noticed the voltmeter gauge was moving back and forth a bit, especially at idle. It was still charging fine but the needle was ticking back and forth randomly, like if you had a high electrical load at idle and you can notice it move when the turn signal turns on and off....But a bit more random. Just a small amount, barely enough to notice. Seems to get better when driving at higher RPM's but it still does it.

Truck runs and starts great so I didn't think much of it until I pulled into the garage last night with my lights on. The lights were dimming and getting brighter in sync with the voltmeter ticking up and down. Okay, its real...so time to dig in.

I put a voltmeter on the battery. It was randomly going back and forth from 14.1V to 12.9V so it was charging, then not charging. I put a new battery and alternator in last year. Not OEM, just average parts store stuff as I needed it quick. The truck hasn't been in any water or rainstorms lately aside from a few car washes. I don't have a winch or big stereo system, its more or less stock so no heavy electrical loads.

Before I look further into this...are these trucks known for having any specific issues? Anything obvious to look out for? Thanks!

 

Nine times out of ten, it's alternator brushes. It's about the only thing that really wears out commonly. How many miles are on your alternator?

Also, since it's a 22R-E, if you get a coolant leak from that pipe above it, it'll dump on the alternator -- check that before pulling the alternator.

 

Alternator is a year old. Probably 2k miles. It's just a fun occasional weekend truck. Gets driven in nice weather and parked in a garage.

No coolant leaks. It's a cheap Duralast alternator....but I figured I'd get better than a year under ideal conditions.

I'll start saving up for an OEM one.

 

parts quality is poor these days. a lot of brand new items fail out of the box.

i have replaced the alt in both of my '87s; one with a denso, the other aftermarket from o'reilly with a lifetime warranty. the denso has been just fine; i'm on my third o'reilly altenator - good thing i got the lifetime warranty. seem to be averaging about 9 months each with them. i just installed the third one last month, and i will be surprised if it makes it through winter.