Ventana/Allstar defrost vent

[jjbsmith]

We bought the 2007 Allstar on a warm day and didn't see the cracks in the defrost vent. On the first cold day this is what we saw.

That was the 2007 vent, which was replaced on warranty. (15 hrs labor)
This is our redesigned 2008 defrost vent.

I thought the sun was the main factor causing the vent to crack so I built a carpet cover.

I now think the bigger factor is the thermal shock that the vent undergoes when the dash heater in a cold coach is switched to defrost.
Our dealer had the Allstar all winter fixing over 30 unrelated warranty issues.
While in the dealer was shuffling the coach in and out of his shop the defrost vent cracked again and the side mount hydraulic fluid heat exchanger burst from the pressure of pumping the viscous oil. The dealer said the coldest day was about -25 degrees C
I suggested to the dealer that he ask Newmar to consider expansion joints in my second warranty replacment defrost vent.
Newmar said forget it, so I called Newmar and I asked how many defrost vents will they replace post warranty. The answer was "maybe one but no more". The Owner Relations Representative suggested, "The cold climate market was just too small and we can't afford to keep replacing defrost vents"
We were not impressed!
As I was pondering the vent while sitting in the coach at the dealer I noticed that the 2008 vent had cracked half way between two vent holes and that the crack was very straight.

An expansion joint was possible and the crack was conveniently located at the 1/3rd point of the vent. All I had to do was cut a matching crack at the 2/3rds point.

It was still very cold at night so I rushed to saw matching crack before the vent had a chance to crack in an unwanted location.
At this point I wasn't sure how I was going to cover the cracks in a pleasing manner but no guts no glory.
I traced the profile of the vent and went back to the shop where I made a crude die out of some aluminum plate.

By this time the third vent had arrived and was in my possession so I was able to design a snap on stainless steel cover for my homemade expansion joints.

It was a bit of a trick placing the trim pieces but they snapped into place nicely.

I will keep the forum posted on the success or failure of my homemade expansion joints.
A side benefit of this most trying defrost vent adventure is the black carpet. I have posted before that the black is very easy on the eyes and cuts down the glare in the cockpit area making a drive on a sunny day seem cooler. Try it with a black blanket you will be pleasantly surprised.
Another side benifit is that our dash was not taken apart a second time.
Also, Newmar saved 15 hrs of labor.

[Dav5942]

Great idea! Fortunately we have stayed out of the cold weather and do not have the problem. Will keep your excellent mod on file, just in case!

[jjbsmith]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dav5942:
Great idea! Fortunately we have stayed out of the cold weather and do not have the problem. Will keep your excellent mod on file, just in case! </div></BLOCKQUOTE>

Dave,
I can bend up a set of expansion joint covers and send them to you. They are not that easy to install but you'er a handy guy.
If you never plan to spend any time in locations below freezing then don't worry about the joints.
The expansion joints must be cut into the vent before any cracks appear. My first vent cracked in a location that was not appropriate for the expansion joint. See photo

[Dav5942]

Thanks Bob, but will hope we don't need them. May regret decision after Alaska next year.

["007"]

Dave if you go in the summer months you could hit +100* in the flats , Big D Buffalo country than if you want to stick around till Jan in Fairbanks your vent may crack at the -65* below.

Bob another Quick tip.

[Dav5942]

Tok(AK) has the record for coldest spot in North America - 86 below! Did not see anything below 45 above last year.

["007"]

Temps were back in winter 57-58 must be warming up in Alaska, did see cold temps in TOK at Forty Mile Road House.

Taylor Highway meets Alaska Highway and travels behind the roadhouse 40 miles from Canadien border to the south.

[jjbsmith]

For those of you who might visit Alberta in the winter you may see -40 a point at which the celsius and the farenhieght themometers read the same. Last winter I think the coldest we saw was about -30C (-10F). It's surprising how many class A coaches we see driving south at these temps. Snowbirds "eh"
I'm sure we will see a lot more cracked vents even in the milder climates because the plastic gets more brittle as it ages in the sun.
The photos I took last year showed the cracks growing during a temperture swing caused by the sun shining in the window on a day where the air temp was maybe -5C (+22F)
The vent had two cracks each of which grew about 1/16". I figure the whole vent grew about 1/2".

My RV technician said that some Fleetwoods use this same vent and they have a cronic crack problem too.

["007"]

Bob, would think Newmar would find some better vent material for MH's going to Canada, because of the temperture extremes.
Your idea is a good one for expansion, will need to put in Quick tips for future reference for people.

[jjbsmith]

007 thanks for the thumbs up,
Not just Canada. The vents are cracking in Iowa. Someone e-mailed me from Iowa with a cracked vent.
Newmar figures the problem is too small to fix. I think Newmar should step up and recall all the vents.