(Not so much) Fun with freezing temps

[Geom]

Hello All,

We've been in the St. Louis area for the last few weeks and it's been colder than a witch's t...oe for a while. Today it warmed up a bit, and we were planning on moving-on. I started the engine and was surprised that despite a bit of initial hesitation, she actually started up nicely. Anyway, I went back outside to do my initial walk-around, and when I got to the engine bay, I thought the sound from the air compressor was louder and more clackety than usual, but I just ignored it. Usually by the time I've finished my initial walk-around, I can see the bags starting to fill and the coach rise to her proper stature. But not this time. When I got back inside, I noticed the warning light (in place of buzzer) was still flashing and the air gauge read 0.

Figuring that we obviously have an air problem, I went to shut the engine off. But turning the main switch and the key accomplished nothing. The engine just kept humming along. Now in a slight bit of worry, I was concerned because the engine was not shutdownable and whatever the air situation was, it was clearly bad enough that even the piston used to kill the engine was affected. After a couple of minutes, it dawned on me to try and "choke" the engine, using that same piston, manually by hand. I was finally able to pull the piston lever forward enough to accomplish that (and learned something new ).

In checking on where the air problem might be, I opened the purge valve underneath the air muffler assembly, and it sounded loud (highly pressurized) and there were splatters of water coming from around the valve drain. So there's obviously water in the system.
I really try to make a point of draining the air system when we get somewhere, but clearly I'm not draining it enough.
The main air tank had no pressure at all, and the air gauge still showed 0 pressure.

In addition to that fun, I also noticed that the power steering reservoir was also pressurized and was spitting hydraulic fluid through the fill hole/cap. After we stopped the engine, it continued to remain pressurized for a few seconds longer, but eventually stopped. While I was inside, it felt like the power steering system was still working ok, because I was able to rotate the steering wheel with ease.

One other odd thing I noticed was after I choked the engine, and killed electric to it, I could still hear something "whirring" in the engine (on the right side, I believe). It would spin up, then spin down, then spin up, then spin down. It did that several more times and then eventually stopped.

So that's where we're at.

I can understand the air system issue. Clearly there's water in the line and it froze. Then when the compressor came on, it was just pressurizing the line between it and the freeze point. There's supposed to be a "safety valve" at the front end of the air-muffler. There is, however, no such thing there. It just has a metal plug in that spot. So hopefully there's no long term damage.
I didn't see any blown air lines (other than the one coming out of the drain valve to the ground).

I do NOT, however, understand what happened to the power steering. There should be no water there, and nothing should've frozen. We've not had any power steering issues before, other than a bit of a squeal when it's cold. We have also had an issue with a leak near the front piston assembly, and while annoying it hasn't been more than that. All things I was going to have our mechanic look at. But clearly something is clogged and not allowing the pressurized fluid from flowing.
I removed the power-steering filter/tube-thing and it looked... "normal". It had fluid inside (although it looked a bit frothy).

I'm not sure at all what that other noise was that kept whirring after the engine was shutoff and with the electric off.
When we turn on the electric, normally there is no sound. So even if the electric was still on somehow, there should be no sound with the engine off. And it just stopped, after a few seconds (15-20), on its own. I'm not sure if maybe the air system could be involved with that, and it was somehow bleeding off??


Anyway, we're going to just stay here a few more days and hope to thaw things out soon. Fortunately it's supposed to get warmer in the next few days.

Any thoughts you have on the air problem, the power steering issue, on what these other issues might be, or whatever else are greatly appreciated.

Thanks
George

[bigred]

The thing we used to do with trucks was to put alchol in the air lines.If you can get some in there it will take care of the moisture.

[MB LeMirage]

Methyl hydrate otherwise known as gas line antifreeze and air brake antifreeze.

Ryan

[goutoe]

is your air dryer working? Do you hear it blouse normally? it could be froze too. Yeah it is always good to know how to shut your engine down manually! been there done that.>>> John.

[Dave5Cs]

Hey George, Just this week our air dyer purge valve on the bottom caught open with grit and would not close. We just took the incoming line and out going line lose and connected then together with some 1/2" DOT plastic line and a few compression fittings. our gauge was at "0" also and then up to 120 after we did that. Another place to check would be your compressor governor and unloader valves to make sure they are working on top of your compressor under the incoming air line to the compressor. But probably just iced up line like you were thinking.
If your power steering is frothing then there is air in it and probably just needs bleeding. If you have been sitting for awhile there may have been condensation in the system somewhere that could have frozen also enough to block a valve in it and pressured the line somewhere where it is not able to move along.
Dave

[John316]

George,

Been there done that, with the air. Your air dryer is frozen. Our AD9 had a heating element in it, that needed to be replaced. Take the dryer apart, get it clean. If you have a good source of heat, warm that sucker up. I have used anything from a big propane heater, to a long flexible tube from the exhaust (when I needed to thaw something in the engine bay). If you don't have any air, my money is on the air dryer.

Good luck,

John

[brmax]

Hmm sorry, Missouri will be a bit warmer tomorrow I heard.
That dryer is probably way up front, and brakes set, and no bag air so while considering all things can one check a relay stud for voltage going to  the dryer.
I have had a lot of air govenors freeze also so consider that sometimes.
That exhaust pipe trick John mention might be the hot ticket if able to muster up equipment.
Good luck there
Floyd

[kyle4501]

A small space heater will provide a suprising amount of heat - if you can keep the wind out. We left one in the engine bay over night and used cardboard to limit the wind - morning temp was 30F.  The engine fired right off & heater provided warm air almost instantly.

A hair dryer works too for providing heat, 1500 watts is 1500 watts.

[Scott & Heather]

Coach didn't shut down cause it's an air cylinder that moves the shutdown lever. No air; no shut dowb


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[Geom]

Thanks all for the advice,

I'm pretty sure that we don't have a line dryer, at least I don't know where it could be.
From the compressor, the line goes directly into the air muffler, and the. out of that straight into the line running to the wet tank in the "air bay". According to the manual there's an optional "moisture ejector valve" in the air bay, but we have no such animal onboard.

I am curious though, so even with a line dryer, this issue would've happened because I strongly suspect the frozen spot is between the compressor and the wet tank. For some reason I thought a line dryer would be further back in the system, and closer to the compressor.

There is also an optional alcohol evaporator assembly that can be installed and its job is to inject alcohol vapor into the intake side of the compressor. We don't have that either, and I'm not sure how else to inject alcohol (or any antifreeze) into the air system. I'm hesitant to take apart the air intake and expose it to just regular (unfiltered) air.
I'm curious if anyone has a trick to get alcohol into the system some other way.

Dave, thanks for the bit on the power steering. I sure hope you're right. Because for the life of me I can't figure out what the heck is wrong with it. It was clearly compressing the power steering reservoir enough for it to spurt power steering (hydraulic) fluid out the top fill hole (screws in with a rubber gasket). I suppose it's possible the pump flow control is stuck and is pressurizing the system thinking that steering was being actuated. It seems to have worked for a little while, but I didn't test it once I noticed the air issue and the pressurized power steering reservoir, and just focused on shutting the engine down

I'm now also thinking since I removed the power steering filter assembly, (to see what was happening) I've definitely introduced air into the system. I suspect some was already in there and is likely responsible for the sqealing we've been getting occasionally. I don't have the ability to jack the front up to bleed the system (as the book instructs) so I'm hoping it'll be functional enough to get us to the mechanic :/

Anyway, it is supposed to be warmer tomorrow. I'm going to fire the engine up again and give everything a look over and see.
Hopefully whatever is blocking the air lines will thaw by then and we'll see what the PS system does as well.

Thanks again,
George

[brmax]

I'm a bit curious where the dryers generally are on a PD 4107 and others in the series.
The dryer I'm wondering about a model on the PD series are they Ad-4 models possibly or a previous one.
Was gandering around early looking at pics in some of the projects area but didn't catch up to a photo yet.
Had wondered a bit does the compressor inlet have the 3" air filter mounted on it style, or have a pipe or hose going to the big air cleaner.
I am hoping for a quick sunrise for you, so firing up the coffee to get it started good luck.
Floyd

[bigred]

GEOM:Most buses {vehicles}with air brakes there should be a connection for feeding air to a disabled vehicle for towing purposes. On my Prevost it is on the passenger side of the engine compartment.You should be able to inject alcohol into this port .

[Dave5Cs]

George, don't know where yours is or if you have one. Mine is all the way up front next to the wet tank. The air goes there first and then to the wet tank. If you don't have one then it goes right to the wet tank.
If you have a shop compressor you may have a air fitting up front in your tool bay. Probably is a Schrader valve like a tire valve. If the wet tank is not getting any air then this one will fill your bags and tanks if the blockage is before it. Take awhile but it will fill them up to be able to run stuff that needs air. Don't go to far unless it hold air well and just for emergency repair or to get it off the road.
If you need to pour in Dryer alcohol you can also take the big line at the compressor head off and pour it in there and put it back on. It will go through the system fast.
Dave

[Oonrahnjay]

... If you need to pour in Dryer alcohol you can also take the big line at the compressor head off and pour it in there and put it back on. It will go through the system fast.
Dave

     If you do it this way, be sure that you don't have an air dryer.  With most air dryers, if you put alcohol in the system and the alcohol gets blown into the air dryer, it will turn the filtering material to mush and plug up the passages in and after the dryer.  Nothing is ever simple, is it???

[Scott & Heather]

I was just going to say what he said ^ you'll be sorry if you find out you did indeed have an air dryer!!

Don't sweat the power steering bleed too much. Mine did that too until it self bled all the air out of the line. Then it never did it again. Drove it 1500 miles without issue after that


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