Fonman

Three quick questions:

1-Did you just come off the road before the jockeying?

2-How hot does it run on the hwy / or in other words how hot to start with?

3-How long did it take to reach 300? Not unusual to take some time getting into the only spot left these days.

Could be as simple as a dirty trans cooler, fan not working properly, temp sender bad.

Seems like the Air Dryer and governor have a little more tendancy to give trouble on motorhomes. I think they get sticky and act up from lack of use.

You could try a new governor, $20 from Napa. My old girl was acting pretty odd recently and a rebuilt air dryer had her back on the straight and narrow.

Your #8 comment has me confused.

Having trouble visualizing at what point you are checking for flow. After the pump or check valve?

Actually a cold hose is exactly what I would expect. Seems like the pumps are flow oriented not pressure so soft doesn’t surprise me.

I would for sure find a qualified Aquahot hot guy if you take it in. Regular RV service departments are likely give you an appt weeks out and then throw their hands up when you finally get a turn. This is not meant as a slam on dealers, by the way.

You have the good (in my opinion) thermostatic wax valve along with an electric over ride which I believe is to run the fan when you have the AC on.

Dunno if this could have any bearing on the first couple, but In general my preference is thread sealer vs teflon tape.

Little shreds can let go and get stuck in valves causing leaks.

Just 2 quick comments to add.

Voltage vs state of charge needs to be measured with no load.

Have you checked the actual voltage at the batteries with a good meter to verify what you are seeing inside the coach is accurate?

Have you had a chance to try and oil any pivots?

Can you “help” it?

OK, I am going to go out on a limb here.

Peoples comfort level will vary, but…

Some facts,

plain water boils at 212

50/50 coolant mix boils around 235

50/50 with a 15# radiator cap boiling point is 265

If it gets 215-220 AND STAYS THERE, I would continue to take the precautions that you have, slow a bit, downshift, keep the RPM’s up, and run it.

A little aside.

Our first pusher, Cummins ISC, 300 hp, the fan ran full time.

We brought it to The chassis manufacturer and had the “2 speed” fan upgrade done. So, basically the fan ran at a very slow speed UNTIL…the water temp got to 205. Only then did the fan finally kick on.

Again, YMMV.

How hot is “too hot” and are you really really sure the radiator is clean?

Some of these coaches have 3 and 4 layers ( rad, charge air cooler, ac condensor, fuel and hydraulic coolers etc) so the rad might look clean…

A picture might help.

Can you start up cold with fluids full and let it run until it is good and hot and look for another leak?

Hopefully over a paved surface?

Typically expansion by itself won’t leave you with enough loss while still driving to set off the alarm. Only after it cools should you get the buzzer.

First my disclaimer. I am not familiar with your coach.

A bunch of things can trip a buzzer. Low oil pressure, (should sound whether in gear or not) low coolant, antenna up, slide out, maybe jacks not fully up.

Typically you would have an idiot light or other indication to tell you what it is complaining about.

Since the air buzzer goes off and it buzzes when put in gear, I would be looking for something besides air pressure. Parking brake alarm should give a visual. Easy to test that one.

If you get different readings the governor is starting to stick.

A new one is less than $20 at NAPA if you can change it yourself before you get stuck somewhere.

End Hijack!

Just to clarify in my own mind. Is what you are calling the reservoir a metal tank with radiator cap or the plastic burp bottle?

i assume you have both? 

Did you happen to look and see if the contacts on roof end of the cable were green?

Does the fuel gauge stay past full when you turn the key off?

Any chance the water pressure is excessive? Time for a regulator?

Hose old and hard?

I don’t think the amps are an issue. As long as the isolator is “bigger” you are fine.

Your voltage regulator is not working properly.

The regulator is likely inside the alternator.

OR…you could have a sense lead problem.

I am not familiar with your coach, but if you have a sense lead, that would be a small wire from the alternator going to the start battery which is how the alternator knows to dial it back when it gets up around 13.8 or 14 volts.

It is even possible it got connected to the house batteries.

17 volts is wrecking batteries for sure.

Any smoke from the exhaust?

The two systems are so separate that I would trouble shoot one at a time. Don’t let the “both” thing cloud your efforts.

If you do find something that carries over to the other then great.

If mine, I would start with the Cummins.

Maybe even a brake hanging up?

Has it been setting unused?

I feel your pain brother. Your story is mine.

(Buncha other drivel deleted)

It seems there are 4 possible connectors.

6 or 9 pin round.

12 pin molex and a ? different 12 pin for DDEC.

IF you go to Silverleaf, then very near the bottom of the page you can click to see the various connectors.

The 9 pin is what I use on my Cummins ISM (M11).

RV upgrade store has some helpful info also.

I’m glad you got her going!

Or possibly start the generator first using the boost?