View Full Version : Keep melting alternators

07-28-2016, 10:25 PM
ST162 with a gen1 3SGTE swap. Same setup as pretty much all the other 3sgte though. I know you guys aren't melting your alternators so whats up with mine. I'm on number 2 now and it is going out after only a few hours drive time. They get so damn hot you can't touch them after even a short 5 min drive. Pretty sure the heat is melting the voltage regulators inside. It's gotta be from my 3" downpipe, but I know other people with large pipes and they don't have this problem. I've tried with and without the OEM alt heat shield and it really makes no difference. The hell man? I'm down to cutting holes in the hood to get heat out.

07-29-2016, 04:17 AM
wrap the downpipe....

07-29-2016, 01:03 PM
wrap or heat coating would help under hood temps. a quick search and this site said their product is able to reduce heat by 35-55%


07-29-2016, 10:15 PM
It's wrapped. Twice.

08-01-2016, 04:12 AM
Is it maybe a wiring issue causing the alt to short out quick, especially with added heat? I have a 165 with 3" dp. No alt ducting or wrap and I haven't had any issues. Have you dismantled the previously toasted one?

08-01-2016, 10:15 PM
That ducting does a LOT to keep the alt cool. The OEM heat shield is also good. I know many run without them and have no issues but the amount of heat in these engine bays is pretty massive and they were put there for a reason.
Also, if you can afford it, doing a ceramic coating on the DP is better than wrapping it in the long run. A wrap will perform admirably for a decent time but the heating and cooling of the pipe will cause condensation to build and over time it will rust whatever is under there.
All up to you. Just throwing in my 2c from experience.

Also, even without those things in place, you should definitely not be smoking alternators. I would look to the wiring and ensure that there are no bad wires or shorts and that everything is in good shape before going further.
The other option is that you got a bad alt from the vatozone, which is relatively common. Go to the wrecking yard and pull one from a Toyota that is OEM. a Camry V6 alt should work just fine.

08-03-2016, 04:01 AM
DP is stainless so rust isn't a thing, but anyways. I went through two alternators that had been used on my engines over the past few years, both were always working good. Visual inspection didn't show anything, I assumed I'd see signs of the voltage regulators getting hot but nothing other than the smell of burnt electronics. I've been over the wiring several times, and checked amperage draw on the system. I went and bought a new one and put it on along with this hood I've had around so we'll see what it does this time.

08-03-2016, 05:03 AM
Check the grounds as well as the mains. Corrosion or rust at those points can mess with things too. This is all just spaghetti though, hopefully one of the things sticks. :)

08-03-2016, 09:12 AM
If you're killing them that fast I'd be looking at wiring issues, not external heat issues.

08-03-2016, 03:16 PM
That's a nice Harley living in the garage with Mudhoney.

08-03-2016, 06:41 PM
Did you do the hood Monkey? or did you buy it from someone who did that?

08-04-2016, 02:32 AM
I can promise it's not a grounding issue. I have huge ground wires that I put on while I was building it, in many more locations than stock. I have checked all three wires of the connector and they are as should be. It's heat I'm tellin ya. So far so good with the vented hood though. Voltages are still steady and in spec after several cruises around town. I got that hood with the all trac I bought. It was a mess with fiberglass resin all over. I sanded it and put some bondo on to hide the ugly. Only thing that bothers me is I can't always park in the garage and I don't want rain getting on my shit. I put plastic over it last night but the wind just blows it around. I'll deal with that later though, got a couple kids interested in buying it so it may be someone else's issue soon.