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Wednesday, September 3, 2014

RV Repair - replacing gaskets on rooftop Duo Therm Penguin Air Conditioners

As many of you know, our motorhome is now 18 years old.  Yup.. it's old enough to vote!

Routine maintenance has kept it up in tip top shape, with 99% of it being done by ourselves.  The few things we have had other people do, we realize we could have done ourselves with a bit more information.  And also I think we would have done a better job, with more attention to details, and cost us much less in labor and parts.

So I try to take pics of the things we do ... step by step... and hope they will help someone else to do the job themselves too.  (rather than paying someone $100 an hour to do it)  

We noticed a bit of water leaking down onto our bed from the back rooftop air conditioner.  This has happened once before on the front unit, and we learned a trick to remove the bottom plastic housing and tighten down on the three big bolts... compressing the gasket a bit more.

This time, we realized the gasket was almost flat and not doing it's job on the back unit.  So we picked up two new gaskets to replace both of them when we had time.   Gaskets are generally available at most RV dealers.  We bought ours at Merz RV in Fond du Lac and they were pricier than what we found online.  We paid $35 each, but Steve wanted them NOW.... and not wait to order them I guess. Gotta keep the local RV dealers in business too I guess.

Here is one I found online so you can get an idea of what I am talking about.  Yup, it is just a square shape of closed cell foam rubber that is sticky on one side.  We didn't use the leveling pads, perhaps those are for some fifth wheels I see with sloped rooftops where the AC unit is attached....  I think most RV's use the same gasket, as the hole in the rooftop is pretty universal in size.

You know Steve... NOW was the time!  In all fairness, we are due for some more rain this week and prefer to not have any more water on the bed!   As it was, the drips hit our LED tv we lay flat on the bed during travel, and we now have a red streaky line vertically on the screen, probably permanent.  Sigh.

I took step by step pics of the process. We have two Duo Therm Penguin rooftop air conditioners but I only documented changing out one of the gaskets.  They both were replaced the same way.

First .... UNPLUG your rig from any power source!   Then assemble all of the needed tools (aluminum sticky tape, oscillating power tool, permanent marking pen, rags & acetone, and a ladder... with an assortment of various screwdrivers, ratchets, sockets and fun stuff like a camera to take pics)

 We looked up inside and saw why our gasket was leaking:

this part might be easier if done with TWO people, but Steve is strong.... 

I would suggest here that before you remove the old gasket material, 
to make some marks with a permanent marker. 
This will show you exactly where the new gasket needs to be attached... 
so it will perfectly line up with the rooftop hole.

If you had marked with a permanent pen here, 
you wouldn't have to guess where the gasket needs to be applied. 

Again, this next part would work better 
with two people lifting, 
and a third person on the inside 
to eyeball how it's lining up 
with the hole in the roof.

You could use duct tape here, but Steve had some of this on hand too

now to take care of a couple air leaks that were never done from the factory either.

We feel the air will flow better by plugging up the leaks
that should have been plugged from the time it was built.

Next RV modification on our "to do" list is putting a riser on the floor under our RV toilet! The toilets in many RV's are pretty low, and unless mounted up on a deck like our Coachman was, they are pretty low compared to household toilets. We had talked a few times about getting one of these riser devices. They run from $40-50 for one so we had kinda put it off.

Just the other day, Steve found one still in the box brand new at a thrift shop for $8.00 and it happens to be the right one for our model of toilet. Stay tuned!


  1. Thanks for the lesson! It is now pinned into my Motorhome Maintenance Pinterest board.

    Now If Steve could fix the noise in our "squirrel cage" in the front air conditioner. Even the guys at Tiffin said they did not know how.....

  2. Yes, thanks for the instructions. My rear unit is acting up so I just run the front unit. Since both ACs blow their cold air into a common duct, one can service the whole rig if it ain't too hot out.


  3. Steve always gets the job done...... He is the best get'er fixed man I have ever come across ...... And the way he helps others too...... He's THE BEST !!!!

  4. Great pictures and step by step instructions. Steve is quite the fix - it man. Having the toilet raised is great!


  5. I wanted to replace our gaskets but we have no access via the inside... sigh.. so I will have to have someone else do it for 100 per hr...

  6. Looks like I need to add this project to my list. This spring I decided the Trek could needed a new toidy and I opted for the riser,too. Today I replaced all the blinds (sure could have used Stevio's help there!) which didn't turn out as perfect as I planned but do look nice.

  7. Veronica, you didn't leave an email address to get back to you with. Hope you come back here for a few more ideas.

    First.. are you sure your roof is leaking from the air conditioner? Many times it is also around the "marker lights" on a roof of an RV and water runs in between the outer roof and inner ceiling and seeks the lowest spot to enter the rig (which is often the AC unit because of the weight) ...

    Second... could your air conditioner condensation water be running INISDE your unit's chamber instead of draining to the outside? On a hot humid day the water runs off our rooftop in a pretty steady stream and amounts to a LOT of water.

    Third... could your unit have a hole up above somewhere that is letting in the rain water such as a crack in the upper cover?

    Hope these things help!


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