A couple of weeks ago I installed a LeeceNeville IdlePro 240A alternator on my '02. This alternator, with upgraded cabling, used to live on my e99 (18 months and 5k miles) before I had to put it out to pasture. No probs when it was on the e99 and no probs up until today.

Upgraded cabling: 1/0 welding cable alt to drivers batt to pass batt then back to alt, with fuses; 1/0 alt to engine ground connection; 1/0 alt to driver batt; 1/0 driver batt to engine ground connection. 2/0 pass batt - starter; original Blk-Or charge line kept intact (connection at pass batt); original crossover remains (but I did not retain this on the e99, just the upgraded one); Where needed, the cable ends were crimped with a proper tool. Battery connections per the photo. Current batteries are 1 month old Interstate sized for the application.

After returning from a couple of errands (total run time 20 min, including 15 min of warm-up), I took advantage of the nice weather to check things out under the hood. Visual inspection type stuff. That alternator was almost too hot to the touch. I have never noticed this before.

Aside: When I first got the '02 in 9/02 and was driving AZ back to ME, the alternator gave up. Did a NAPA parking lot swap out in TN. After a month or two I saw the dash volto-o-gauge moving around. Since I had it, I quickly installed the above noted L-N IdlePro, but did not install the upgraded wiring. Took it for a quick 5 min spin and noticed the alternator was pretty dang hot, including the charge wiring. OK, I guess you really need the upgraded wiring when adding these things. I took the L-N off and traded in the NAPA alternator. Fast forward to a couple of weeks ago when I finally got the chance to install the whole smash. No problems with basically the stock charging system from 9/02 to 12/23.

All connections are tight, secure, and clean. I did not crawl under the truck to check the engine mounted grounding..yet. 14+V at the batts while idling. I have a NOCO dual batt tender on-board. When I plug that thing in, it takes less than 10 seconds for it to register "green" on the status lights (which is float/maintain). No different now. Nothing to suggest one of the batts is having a tech difficulty. Batteries and cabling are not warm to the touch. Starts up as expected for the cold weather up here, but with an asterisk. No added electrical gear at the moment.

The asterisk: For the past week or so I have noticed a slight/subtle decrease in start performance. A couple of revs longer on the crank, a few seconds longer of that rough time upon start, a bit more white exhaust. I am thinking that maybe a glow plug or 2 (or a bank) may have headed south. That was why I was doing the visual inspection in the first place: to make sure the valve cover plugs were good, no obvious chaffing, etc. Everything checked out on that front. RiffRaff sourced glow plug relay installed 12/23, with no probs to date.

I could touch the case, but I couldnt keep my hand on it. Since the truck is always on a batt tender, and I ran the truck for enough time to recover from the first start of the day (at least I think I did), I do not believe it was a catch-up battery charge thing going on. I also dont think it is a draw through the alternator, because the alt did cool off to ambient temps in short order (about 30F up here this afternoon, and I had the hood open into the sun). Belt tension seems normal - no squealing or other belt/pulley noises since the install.

Back to the original question: how warm is too warm? Something going on with the GlowPlugs?

Photo is from the original install back in 2021. Note: the cable from alternator-drivers side - crossover - passenger side - back to alternator is a continuous run. Those batt terminals allowed me pass it through instead of cutting the cable.

 

Are you running a lot of accessories? Big stereo always on when the engine is running or something?

 

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Nothing. All stock electric load wise. I don't even have a radio in there (there is a story).

 

so what's the question? how hot alt's run?
I can tell you that you can't keep your hand on an alt, that's normal. everything under my hood gets too hot to keep a hand on...thats metal

hopefully I answered correctly and not sitting out here looking like an idiot

 

Yeah, a short 20 min run with most of that idling, the alternator probably hadn't even finished topping up the batteries from the glow plug and starter drain. Just being bolted to the engine will make it hot. If it's working too boot then she'll be damn hot. Like hotter than two chicks making out hot, and I think we all know how hot that can be.

 

as just said, topping off the batteries after a cold start requires a lot of Amps.

as for how hot is too hot?
the wires won't melt until way up there, 400*F plus.

use an IR temp gun, and if it is Hood temp plus 100* it is just fine.
so, running down the road, I would expect it to be 220* or more.
300*F is not too hot


I read you have fuses in the Alterator feed line?
if so, those fuses and Holders better be rated at nearly twice the output of the Alternator, or they will cause a High Resistance, forcing the alternator to climb to a higher voltage output, making it hotter.

use that IR Temp gun and shoot the fuse terminals, hot? replace them.

 

@pvdiag

After really reading, rather than my usual skimming, every word of your opening post, I was intrigued by, and impressed with, how you painstakingly anticipated and answered all of the usual questions preemptively.

Based on this and your prior posts, I trust your judgement, and believe your alternator is too warm. If it was normal, I don't think you would have pointed out all of the circumstantial details so painstakingly.

I have the same alternator, but not the same truck. 2002 and up Ford Super Duties are wired a bit differently than my 2000 and your old 1999. Still, having the same alternator means I have an interest in learning what is going on with yours, because my Leece-Neville is never too hot to touch or keep my hand on to support myself when nosing around the engine bay after driving.

Thinking about when is warm too warm, I can recall my original production 6G small case alternator, which lasted about 17 years, that was equally cool to the touch and useful as a body prop to nose around the engine bay. Until the day that it failed. THEN that little 6G could fry some eggs. That was too warm, and that excessive warmth was the clue that led to diagnosing my original 6G alternator's failure.

If, in the estimation of your life experience, you question the high amount of warmth coming from your Leece-Neville, which you already have had 18 months of experience with, then I would listen to your spidey sense and accept that warmth as an early warning that something may not be quite right in the kingdom of Denmark under your hood.

Let's look around...

The first suggestion that came to mind while reading your post is to inspect the B+ terminal block directly on top of the driver's side front wheel well liner.... which is a new for 2002 electrical connection that fails a lot (corrosion develops resistance), and that our 1999/2000 trucks never had.

The second suggestion that came to mind is influenced by my personal bias against any battery connection that relies on the torque of a set screw in a vibration prone environment, made of material that may have a different coefficient of thermal expansion, that can heat jack the set screw over time.

Subscribed.

 

Ok, some data.... I have a FLIR I7 thermal imaging camera, and a decent multimeter. I'm going to figure this out....

Photos will be in a separate post. After I upload one, it deletes everything I typed prior.

Truck off for 16+ hrs overnight, 10-12F at first light, 17 when I went out to start. Batts @13+/-V off the tender, but were on it for the previous 16 hrs. Alt casing at 17-20F ( I should have taken a picture).

Had to cycle 3x. Like I noted earlier, I think I have some GP thing going on. And it wasn't all that cold. Just before start, batts recovering from 11V up to 12.2 or so. Also, I don't crank excessively, if it doesn't catch after 3-5sec, I'll start over.

​​In the time after it started and to get back to the front: batts @ 14.4, alt casing on top at 19-25F.

*After 1 min, 14.4 and 30F. Voltage will remain at this value throughout.
*2 min, alt casing 85F. First photo.
*4 min, 95-100F
*8 min, 113-115F, about 330 at an internal point. You can see it in the photos (next post)
*17 min, 115-ish, 350F at internal hot spot.
*About 20 min, same stuff, but this time took pic of the pulley.

Had an AHA moment. Maybe the prob was the hood. Up to now it's been open. The alt makes a slight indentation in the hood insulation, so I thought maybe it isn't cooling itself that well when its closed and driving. Close the lid and kept idling. 5 min later...115F on the casing, and that internal point is still 330-350F. Maybe that isn't it.

After 1 hr from first photo, which included 20 min of driving, nothing has changed. Casing at 115 or so, internal spot still around 300 (it's hard to capture the highest temp with my cell).

This 115F is a comfortable temp, you can leave your hand on it, and is generally what I have experienced in the past.

Today I idled about 15 min longer than yesterday (as I collected data), but drove about the same distance. Not quite the same conditions, but close, including outside temps (night and day). The only elec load was the heater fan. No lights, radio, nothing plugged into the 12V socket.

Now I'm stumped. From the perspective of batt charging - as noted by another poster - both days were the same: 3x GP cycles, on the tender overnight, and idling/driving 45 +/- min. Close enough, but very different situations.

This now puts it as an intermittent issue - the worst scenario.

One thing to add about when I observed the hot alt yesterday. The truck had been off for about 30 min before I discovered it. So it had a little time to cool down, and it was still nearly too hot to touch.

I'll keep an eye on things. Suggestions and opinions always welcome!

 

Local hot spot after 17 min

17 min - pulley

2 min after start

After 1 hour. Didn't quite get the top of casing when photo snapped. Still at 115-120F or so.

After 17 min

 

I do. One at the start and one at the end of the cable loop. Don't know if I needed to do that, but it made sense at the time. I used a 1 into 2 type fitting on the alternator hot side. They are rated for 150A, which is the rating of the wire based on length and size. So I think with 2 like I have, I am slightly higher than the nom 250-ish output of this thing, while still preserving line protection.

 

35-40 total. I'm good for 15-20 min of idling before I take off during the winter time.

I know that it takes awhile to replenish the batts after a start cycle. I know the stock alternator @ 120A (or whatever) huffs and puffs to catch up. But I have to say, I never noticed that it got ripping hot.

 

I know from reading about all the big alternator upgrades on the camping van forums that your alternator will get hotter when idling vs running at speed, it needs some RPM so it's fan can move more air. I also know that an alternator can get pretty dang hot when it is supplying amps even in the 30-50 range. I don't know how hot is too hot though.

 

I will take a closer look at that B+ term block. You seem to have some super-duper encyclopedic knowledge of these vehicles, like knowing some subtle-ish power distribution details between model years. It has not gone unnoticed to me on many of your posts.

I hear you on the set screw thing. It wasn't until I started using these things that I realized the potential weak link. Because of that, it is a routine check every time I pop the hood. So far so good on those, though. I know I have had to do a tighten here or there, but it isn't a chronic deal.

 

Engine temps will actually rise in the first 10-15 minutes after shutting down. If you're seeing temps of 300+ in the core of the alternator then shut everything off, which stops the cooling fans, that 300+ is still in there. It will radiate outward raising the case temperature. I don't know that this would explain what you experienced before, but it would contribute I'm sure.