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rfsod48

Engine Block Heater & Air System Questions In Freezing Temps

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Roland and I have been trading PM's on this.  Probably good information for many, so will continue here.

Roland asked: " Got my manual and it says I have automatic tanks. Should I be worried about air dryer? How would I check it, find tank and do a manual dump?"

Since you are not able to see what comes out of the tank drains (unless you just happen to catch them during purge cycle), it would be very difficult to use them for a "report card" on air dryer condition.

And, air dryer maintenance is one of the more neglected items on many coaches, since it is a new component for most new DP owners.

Air dryers need to be serviced (filters changed) or replaced about every three years.  The main "got ya" if they are not serviced is that the desiccant in the filters can break down and get in the air system, clogging LOTS of valves in air suspension and air brake systems.

My strong preference and what I do on my coaches is to just replace them with a FACTORY (I.E. THE FACTORY THAT MADE THEM, NOT, REPEAT NOT A "REPLACES" OF UNKNOWN QUALITY) REMAN.

That way, not only the filters, but valves, heater, etc are all new and to the high standards of the OE dryer.

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18 minutes ago, rfsod48 said:

Is this something you do when it is above freezing or even when it is below freezing?

If there is water in the tank, it will not purge if below freezing, as it is ICE.

Now, if you air dryer is functioning as it should, its built-in 12 VDC heater should allow purging of moisture at the dryer.  Again, it is only with a failed dryer that water will reach the air tanks.

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A good idea.  Another option is to alternate replacement with FACTORY reman and just filter replacement.  So replace now, three years from now new filters, 6 years from now factory reman....

 

Don't know your skill level or location of your dryer, but it is a pretty simple operation-- replacing is much less mechanically demanding than properly rebuilding one.  Yes, air has to be drained from system (in case the tank check valve is defective) and you will need to block the coach up so you are safe working under it.  Then, basically hand tools.

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Don't know how my answer got to the end of this chain...:rolleyes:

Linda replaced hers earlier this year & has the pictures to prove it. 

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Roland.  Did you by any chance air up your tires before the cold set in?  I took mine to 115 all 8 of them!  Bet mine will be 5 to 10 pounds less, when I check them in morning before we leave!

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My simple test of my ISC Cummins engine heater; I turned the switch on, came back 2 hrs later, turned on key and temp gauge read 80°. The outside ambient temperature was -4°F.

Sure it allows the starter to work more easily, but it does nothing to warm anything but the coolant and engine. One must drive judiciously until every drive train component is warmed to operating temperature in sub-freezing weather.

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20 hours ago, manholt said:

Linda replaced hers earlier this year & has the pictures to prove it. 

:wub:

But the hammer to the inverter is still my favorite :lol:

Roland, I have found on a large diesel 3-4 hours with the block heater on and a small Diesel (8 liters or less) 2-3 hours is adequate. Some engines have a thermostatically controlled block heater, (comes on and off as needed), you would need to call your engine manufacture with the engine serial number to confirm what was spec'd on your coach. When temps are below 50 I switch ours on just before making breakfast (switch is next to the shift pad up front of the coach) after we are all cleaned up it goes off and I start the coach. I have a Scan Gauge unit mounted to the instrument area, when I switch the ignition on I can see the coolant temp, I am not a fan of starting a diesel in cold temps.

Air dryer; I replace our complete unit as Brett mentioned at the three year interval. My dryer runs around $190.00 for a complete remanufactured unit and it only takes around an hour to replace it. My air tanks I drain once a year at the time of the oil change, haven't found any water in them yet, but part of Monaco's cold package was heated automatic tank drains, personally I'm not a fan of them but I guess they or the dryer is working properly. Blocking the coach properly is critical before crawling under even if just to take a peek around.

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Carl, we did air up the tires to 110#, last I checked them with the cold they had dropped to 105#. 

Joe, I plan to check into the air dryer while we are in Arizona, not sure if I will attempt myself or go to Freightliner. I think I will use Freightliner and have the entire chassis serviced.

Ray, I agree with slow start and do practice that .

Thanks all for help, we have moved up leave date to Friday for a better weather window.

Roland

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If you do not have automatic purging systems you should purge the air tanks at least monthly but especially in freezing conditions.  If you have a  Freightliner chassis there is a pull cord behind each front wheel. The cord looks like a loop of braided wire.  Pull the wire and you release air from the air tank along with any built up water.  Note: This only applies to coaches with air brakes.  Hydraulic breaking systems do not have this problem.

 

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7 hours ago, aphotowizard said:

If you do not have automatic purging systems you should purge the air tanks at least monthly but especially in freezing conditions.  If you have a  Freightliner chassis there is a pull cord behind each front wheel. The cord looks like a loop of braided wire.  Pull the wire and you release air from the air tank along with any built up water.  Note: This only applies to coaches with air brakes.

 Hydraulic braking systems do not have this problem.

 

I agree, checking the tanks for signs of water or worse white powder (desiccant broken down) is a very good idea. Basically a "report card" on the functionality of the air dryer.

I would restate the last sentence: "Hydraulic braking systems do not have this problem."  There are coaches with air suspension and hydraulic brakes.  Their air systems have the same compressor, dryer and tank arrangements as those with air brakes. Our 2003 Alpine 38' was an example of just such a set up.

And, yes there are a few coaches without air dryers.  On these much more frequent tank draining is needed.

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