Dash A/C - Page 2

Airstream402001 · 04-16-2002, 10:26 PM

Hi Peter and Alan
The manual for my 87 reccomends using the generator and roof air in hot weather.
In cold weather, go ahead and use the dash air ?
Go figure
Cliff in Indiana

FrankR · 04-17-2002, 12:16 AM

I hope NOT to step on any toes........ But using ball vales to bipass a heater core is not wise........... because.. the water in the heater becomes stagnant and foul smelling. This is not a good mix for any coolant. Stagnant water will grow some bad stuff. The price of the valves is not of much value. An easy bipass is to just use a plastic or brass coupling to couple the in and out hose together. It is good to flush out the core with the garden hose and finally blow out the remaining water with air. Replacing a heater is nearly as costly as a radiator replace because of the R&R labor. Any one who can get an engine over heat to run cool using the heater needs some serious cooling work. In many cases, a lower heat number can be used in place of the recommended temp t-stat. Lots of smog built Chevy V-8 350 engines call for a 192 degree t-stat. We install 180 degree t-stats with no problems... With a 192 degree t-stat and and a 15 pound cap, the engine cooling system can operate as high as 220 degrees. A good cooling system uses 60% distilled water, like in a clothes iron, and 40% coolant. Coolant test strips are available to check for correct chemistry. The best cooling system will not do any cooling with bad belts and adjustments. Not real tite...just rite. Lefty...loosey Righty ...tighty... Frank

williamhenshall · 04-17-2002, 01:11 AM

Anyone else who has had AC issues might find this of interest...

I bought my 1990 345LE from a gentleman in his 70s who had bought the coach and driven 28,000 miles in 10 years, with most of the mileage in the first 2 years he had it.

When I got it all rubber items were perished, as well as brakes, shocks, hoses, belts, airbags etc. The drive train and pistons and gear box etc were perfect (the expensive stuff, or should I say the more expensive stuff...) and the tires had been recently replaced too.

The dash heater/AC didnt work at all and the guy told me it never had and to use the gennie/roof AC

The problem is driving here in CA I am often on the 5 between LA and SFO and the evening sun is on my face and the roof air is on the back of my neck...

So I tried to get it fixed. I replaced or fixed all vent hoses, and the compressor. This kind of fixed it. At least I had hot air and vented air but the AC wasnt working at all. It turned out that the new compressor was faulty.

Next the service tech found a vacuum hose loose under the hood, the one that goes to the little globe shaped vacuum pump on the passenger side.

This fixed the air coming through better and also returned my vacuum gauge to working ok.

Next the facia plate with the air controls broke and fell into the dash itself. This got fixed by epoxying it together and remounting it - a royal pain to get it in the right place. I was told the part is not available any more.

The faulty compressor is still not replaced as I haven't been back to the GM dealer yet but I do have some cooled air. I think this fixed should do the job.

It makes a big difference for driving comfort to have the dash air working.

I guess my take on it is that the roof AC is obviously much more powerful and if you need to recharge batteries well it's a no brainer to use it.

Funny though I actually prefer the dash AC when on a 600 mile trip.

Anyone have any real figures on how much more HP and gas is used up by running the dash AC? I think my gennie (the one that this coach comes with..a 6.5 Onan I think) uses about .7 galls per hour...

Best wishes

Will Henshall

PeterH-79MH · 04-17-2002, 06:46 AM

some simple facts (measured in 2001, Texas summer)
outside temp 100
inside with roof A/c ~80
cab temp with roof A/C, without dash A/C ~95
cab temp with roof A/C, with dash A/C ~80-85

driving all day in 95 degrees with the sun blasting through the large windows gets very old.
Generator shut-off @1/4 tank will send the temperature to 110 degrees within a few minutes.
A great recipe for cranky drivers and passengers!

FrankR · 04-17-2002, 11:40 AM

To improve cooling requires some patience and work. A good a/c unit may be working to the max and still not provide good interior comfort. To maximize the a/c performance a auto a/c tytpe probe temp gage is required. Some basic temp readings in any given area should be recorded to make later comparisons. A a/c unit that produces 40-44 degrees F at the front dash discharge duct is doing good. This temp discharge air should not change after established. Cooling usually improves after vehicle is moving forward. After getting a low air temp, the trick is keeping low temps in cab area. Some RV's use a curtain behind the occupants to creat a smaller area to cool. The a/c unit is in fact just removing heat, lots of it, at the rate os about 18000 per hour.Covered side windows also help keep hi temps out. It requires a helper to see if the control linkage is traveling to the full on position for the air door. A person inside and one out side can observe linkage travel and adjust for max. Most linkage are adjustable with just a single hold down screw. When the a/c unit is operating, the heater hoses can be checked to notice any temp change to determine if the control is stopping water flow. It is hard to reduce any temps when the heater is also heating incomming air. It is good to check the control vacuum at several places to observe any leaks or poor conections. The fan clutch is an important part of the a/c system along with drive belt tension. Frank

ALANSD · 04-17-2002, 01:14 PM

visit Idaho the skies are great!!
also nice workshop on the other post...

PeterH-79MH · 05-20-2002, 07:07 PM

On my recent trip I did some water temp checks.
I have no water temperature problems running my dash a/c, even when stuck in traffic. The outside temperature was around 90 degrees.
I was surprised by the different temperature running with the heater core shut-off valve open or close. With the core closed, I was running a good 15 degrees hotter (195 degrees). I guess the core acts like a small secondary radiator.

Inland RV Center, In · 05-21-2002, 09:49 AM

It is considered a "trick of the trade" to turn your heater on, full bore if necessary, when making a loooooong climb, as well as shutting the dash air "off."
It does add additional cooling for the engine.
Better to be warm for a bit, instead of standing by the edge of the road, looking for help. Andy

ALANSD · 05-21-2002, 09:50 AM

Another concept open for opinions- I saw replacement fans at the Parts store yesterday- aluminum blades with rubber edges riveted on for max air flow, "even at low rpm". Might this be a good add on? JC Whitney has these also

Also what about using that "water wetting" agent.?

thenewkid64 · 06-03-2002, 01:15 PM

Well I finally broke down and had my Dash AC Fixed. All it needed was a new fill valve on the High Pressure side and an evac and fill. While they were working on the Coach I had a new fan clutch and Alternator installed as well. Best $312.00 I have spent so far.

Now for the rest of the to-do list.......... Maybe I should just go rob a bank

Just kidding.

kzener40 · 08-03-2002, 07:38 AM

I know it's been a while since all you talked about the dash a/c but I need some advice. My dash a/c doesn't throw out the air worth beans....I had it checked by a mechanic. He said the motor was working fine and the 3 speed switch was working but on high the amount of air coming out is really weak. He wonders if possibly there could be a duct or hose clogged or loose. Has anyone ever run into this? If so what's the best way to check? I assume you go through the dash to check it out. Do you get a good amount of air blowing out in you MH when you have it on high?

Any advice on how to get the air pouring out (if possible) would be appreciated. As mentioned above, the roof a/c's are great for the passengers in the back but even with those on the driver seems to bake without some air up front....

Thanks
Ken

Inland RV Center, In · 08-03-2002, 10:02 AM

Ken. Check the water heater control valve. They have been known to leak, therefore adding heat into the AC duct.

Andy
inlandrv.com
airstreamparts.com

kzener40 · 08-03-2002, 10:14 AM

Thanks Andy. My problem hasn't been so much the air isn't cold. There's just not any real volume blowing out. Even on high speed it seems to barely come out, like something is clogged in the vent. Should I take off the dash and start exploring around to see if anythings come loose?

Thanks
Ken

thenewkid64 · 08-03-2002, 10:50 AM

Ken,

The dash AC in my MH is a modified aftermarket type unit. Kind of like the ones that folks added in the 06s and 70s to a non ac car. It has a front cover that all of the AC Ducts hook on to. I would assume yours would be somewhat the same. Mine is mounted in the center of the dash over the doghouse. I have som of the same lack of blow. It has low, and med. but high is no better than med. I wonder if there is a blower motor resistor that could be bad, not allowing all of the power to get to the blower????

We are getting rain again here today, this just might be the project to work on. I will let you know if I find anything.