Community Forums

TinMan Trvlr · 03-29-2014, 08:14 AM

Since several posts have stated Newmar will not supply an engine preheat loop from the Oasis system as a factory option, have any owners done it themselves or had it done by a 3rd party shop? I am told that the parts and replacement Oasis three rocker switch panel for inside the front cabinet are worth less than $400.00, and that the wiring is already in place in the cabinet.

What challenges or issues have those of you who may have done this encountered? Any photos?

For those of us who may have to park without power in up to minus 40 temperatures when heading south or back home, the engine preheat loop seems a much more sensible, energy efficient way to warm up the engine after a cold night of boondocking than starting the non-preheatable Onan generator to run the block heater.

All input from those with personal experience will be happily absorbed.

PDR John · 03-29-2014, 09:57 AM

You can have it installed when they build the coach. Redbaron73 did on his 2013 Dutch Star.

We were going to have Newmar add while they had our system drained last spring, but we would have had to wait a week for the pump to come in.

You will need to purge the whole system of air to do it, which can be a pain. The tech doing our work and I went through what it would take. It's not hard, just tedious.

Here's a link from RVcruzer adding to his Aqua Hot system.

RVcruzer.com - Installing the HydroHot Engine Preheat System

redbaron73 · 03-29-2014, 11:32 AM

All the wiring and hose exists. It is a splice and install of the pump and then connecting the wiring.

As PDR John stated the problem is the purge of the system. It had to be done twice on mine and I still have some air pockets that worked out this last month when I used it again.

96 Wideglide · 03-29-2014, 11:59 AM

So, if I've got this right, without the engine preheat, you also dont have coach heat from the engine while your going down the road. (Other than dash heat)

spinn · 03-29-2014, 01:35 PM

Quote:

Originally Posted by 96 Wideglide

So, if I've got this right, without the engine preheat, you also dont have coach heat from the engine while your going down the road. (Other than dash heat)

The 2 are separate systems. The preheat loop is independent of the coach cabin loop.

Hope this helps-Steve

96 Wideglide · 03-29-2014, 01:50 PM

Ahh, I see.
Always assumed they were the same loop, just used in reverse.

redbaron73 · 03-29-2014, 04:12 PM

The waste heat loop is installed by newmar factory. This loop heats the oasis from the engine antifreeze.

The add on for preheat cuts into this line and adds a pump. The pump allows it to run in reverse.

The boiler fluid never mixes with the antifreeze, stays separate.

TinMan Trvlr · 03-29-2014, 09:00 PM

Redbaron73, when you had the engine loop added, was it done by a service shop? Did you have any engine cooling issues or Oasis heating issues due to the retained air in your cooling system? Do you know what the "trick" was to finally purge the remaining air from your cooling system? Also what motivated you to make the "mod" of adding the engine preheat loop?

TinMan Trvlr · 03-29-2014, 09:05 PM

PDRJohn, thanks for the link to the process of making this mod on an Aqua Hot system. I'll review it and see if Oasis offers instructions and recommendations for a successful install.

redbaron73 · 03-29-2014, 09:36 PM

Quote:

Originally Posted by TinMan Trvlr

Redbaron73, when you had the engine loop added, was it done by a service shop? Did you have any engine cooling issues or Oasis heating issues due to the retained air in your cooling system? Do you know what the "trick" was to finally purge the remaining air from your cooling system? Also what motivated you to make the "mod" of adding the engine preheat loop?

newmar did this for me on the production line. When I did my pdi delivery at Newmar, I had to have the heater upgraded which caused the lines to be opened again. This introduced air in that side, and took a lot of purging.

Thinking about my previous statement, the air in the system had nothing to do with the pre heat loop.

The final purge on the system is best done with usage. It will purge thru the overflow canister.

I got the system installed because I don't want to have to rely on the generator to preheat engine overnight when boon docking in cold weather.