E-450 temp and electrical warning light

[bajajoaquin]

have a 1998 Class C camper on an E450 chassis with a V10. I’m currently pulled off in a campground because it’s like 110 out and because of my issue, I didn’t want to drive it in the heat.

Engine has 24k on it. I’ve put the last 5k on it since buying it last November. I put a Scangauge on it and monitor my coolant temps and try to keep it 209 or under. It typically runs 193 for about 20 minutes then goes to 197/198 unless I’m on hills.

After climbing a hill that requires 3rd or 2nd and it gets hot (209), then shifts back up to 3rd or 4th (OD), and I let off the gas completely for the downhill, the battery light will come on the dash. It goes out if I touch the brakes and will sometimes go out if press the throttle. After it cools back down to 197 or 193 on the downhill, it goes away.

Because it is so hot, it was running at at a constant 202 to 204 and the light kept coming on.

I pulled into the next campground I saw and plugged in. I’ll sleep for a bit and drive the rest of the way in the middle of the night when it cools off.

anyway, sorry for the long post. I wanted to give as much detail as possible. Any ideas about what’s going on? Anything I can do to help it? I’ve got about 800 miles to home and an appointment with a mechanic but want to keep the family out of a tow truck if possible.

also, what’s actually considered “hot?” The factory gauge doesn’t move at all between 180 and 211.

thanks!

 

[Rebuilder]

I'll chime in.... I definitely wouldn't worry about 209. I'd personally only get concerned if it goes over 220 and keep rising. Not sure about the battery light but, and this is a big reach, but maybe your belt(s) are loose or slipping which might result in reduced cooling fan and alternator speed which in theory would result in overheating and lower alternator output.... like I said that would be a big reach but that's the only thing I can think of that would affect both systems. Unless you have an electric fan?

 

[bajajoaquin]

So I thought I’d reply and give an update. Thanks to all who offered their opinions.

I have a good mechanic home in San Diego (finally: had to search a bit). He says this generation of alternator is dual wound and can cause weird things to happen. It was only putting out 13.3v when under load and he suspected that it was getting hot and the change in RPM at the crest of the hill was causing one winding to go astray. He said it’s also the original alternator from 1998, so even with 25k miles, it’s time to change it.

He also thought it was running a bit hot given how easy I go on it, and inspected the radiator but decided that it was fine but the thermostat needed replacement. We yanked out the aftermarket alarm that would set itself off silently but disable the starter while we were in there.

He also found the serpentine belt to be in need of changing the AC to be low on charge and found my grinding wheel noise to be a stuck rear brake caliper. None of these issues were found by my previous mechanic even when I specifically asked about my concerns in these areas.

TL;DR looks to be an old alternator and bad thermostat

 

[vintageracer]

Just read this post and was going to suggest your alternator could be your problem.

Had similar issues with one of my Ford trucks in the past all related to the alternator putting out 12+ volts but little to no current (amps).

Remember Ohm's Law:

V = I (Current/Amps) x R (resistance).