Beautiful Banff in our OEV Summit and a hydronics dilemma

[Trail Talk]

We took BLITZEN to Banff National Park for the week and enjoyed warmer conditions. The x-country ski trails are melting out fast and what is left is pretty icy. Nevertheless we had a great time skiing an area adjacent the Lake Louise ski hill that just reopened after a two year closure.



After a couple of nights at Lake Louise we drove to Banff and the superb Tunnel Mountain campgrounds. It was very quiet and we shared hiking trails and viewpoints with only the elk.



We have a winter ritual of snowshoeing up Sulpher Mountain's backside and down the front but this year, after walking a couple of miles to the trailhead, we found it closed! Turns out they are hauling and burning deadfall. So instead we hiked up and down the front tourist route under the gondola. In previous years one could get a free ride down if you walked up, but under new ownership and after extensive, expensive renovations the one-way ticket down was $25/person!! The cafeteria where you could enjoy your pack lunch while admiring the view is now a chic restaurant with reservations required. Ah, Banff....



After several trips this winter in the OEV Summit, we've become very comfortable with its features and layout. The combination of our F350 cab/chassis and OEV's integrated cabin remains a pleasure to drive in all road and weather conditions. The extreme cold experienced during the Polar Vortex event in February confirmed that the Summit is completely suitable for such severe weather. We did discover a few locations of thermal bridging which created interior frost build-up and will have to give some thought to a remedy before any extended winter travels.



The one issue that continues to annoy both OEV and us is the hydronics. OEV has attempted to remedy the issue and incremental improvements have been made. We still have a leak from the coolant overflow tank and, with this trip, one of the 2-way ball valves. OEV discovered early on that the truck engine produces more pressure than the Webasto, which is the apparent cause. At this point, it now leaks only in one scenario: when the truck circuit is used to heat the cabin's interior while driving down the road. If I reverse the situation and use the Webasto to pre-heat the truck engine, no leak. If I close off the truck circuit completely and heat the cabin with the Webasto, no leak. So I'm curious to hear from anyone else with hydronics experience - any leads or suggestions I can pass on at our next service trip?



A post-trip wash always feels good. The winter studded tires have been exchanged for summer Method 701HD rims and BFG T/A KO2 tires. We also had Bushmaster front OE-style flares installed, along with Ford's plastic inner fender liners and front Gatorback mud flaps. Also considering swapping out the front air dam for a smaller version from the 2WD models but, knowing we will rack up more miles on highways than back roads, hesitate because of the possible effect on fuel economy. If it takes a bashing this summer, we can make the call.

 

[Blowby]

Thanks for the great trip report,appears to be a beautifal area that hopefully one day me and the missus can also appreciate.
Also appreciate the updates on your live in experiences with the OEV as this is also one we have been considering.

 

[billiebob]

FABULOUS to see an EXTENDED CAB rather than the wasted spece QUAD CAB !!!!
Pretty sweet wheeler, almost looks aerodynamic too.

Nice rig, great pictures.

ps, i doubt air dam changes will make measurable fuel economy differences. Speed on the other hand, like the difference of cruise at 65mph vs 55mph will make a huge difference. The truck is relatively aerodynamic, the box is not. A fiberglass nose cone might make a measurable difference. I'd just get rid of the airdam completely. Replace it with an aluminium skid.

We always focus on the front, but the rear, drag is equally important to increasing economy. YJ vs TJ is a great example, the TJ has more tumblehome in the roof than the YJ. That BOX says fuel economy is a non starter. SPEED is the only factor.

My TJR towing a SquareBox at 55mph gets a 4mpg boost over towing at 65mpg.



Recognize this spot ??

 

[Joe917]

We have a Webast ThermoTopC with a Mercedes 917AF chassis. The heated towel bar in our bathroom is the high point of the system. No matter how many times I fill it to the top, it always seems to settle with the top 3 inches or so with air. Once it settles at that point it no longer looses coolant. Where it blows off the extra coolant I don't know. Have you waited long enough for the system to stabilize? perhaps it needs some room for expansion in the camper side of the system.

 

[Trail Talk]

We have a Webast ThermoTopC with a Mercedes 917AF chassis. The heated towel bar in our bathroom is the high point of the system. No matter how many times I fill it to the top, it always seems to settle with the top 3 inches or so with air. Once it settles at that point it no longer looses coolant. Where it blows off the extra coolant I don't know. Have you waited long enough for the system to stabilize? perhaps it needs some room for expansion in the camper side of the system.

Interesting, thanks for sharing your experience with the Thermo Top C. LOL, nifty idea with the towel bar . Initially there was air in the system, which sounded like popping corn, but that was rectified and hasn't reoccurred. My system has a 1.5 litre expansion tank which fills up then leaks out an overflow port onto the ground. The truck's coolant level drops correspondingly.

 

[Trail Talk]

Here is the layout of my hydronics; cabin circuit in orange and truck circuit in blue. Leaking now occurs only when driving while on the truck circuit, but the leak is at one of the cabin valves and out the cabin coolant overflow tank. If higher pressure from the truck circuit is forcing past the valves into the cabin circuit and then out the overflow tank, what is the remedy? Somewhere the system needs to relieve this excess pressure or resist bypassing the valves.

 

[Joe917]

Here is the layout of my hydronics; cabin circuit in orange and truck circuit in blue. Leaking now occurs only when driving while on the truck circuit, but the leak is at one of the cabin valves and out the cabin coolant overflow tank. If higher pressure from the truck circuit is forcing past the valves into the cabin circuit and then out the overflow tank, what is the remedy? Somewhere the system needs to relieve this excess pressure or resist bypassing the valves.

View attachment 649466

This is a professional Webasto install. (1994) original unit replaced 7 years ago.

 

[WanderingBison]

Have you considered isolating both circuits and using a plate heat exchanger between the two loops?

This is how I have my DIY install setup and it allows using engine heat to heat the cabin/hot water. Engine coolant is circulated by the engine side.

It would require a second pump placed in the engine coolant loop to preheat the engine.

As a bonus, you lower the risks of the cabin/water heat system having a failure and affecting the engine.

Food for thought.




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[Trail Talk]

Have you considered isolating both circuits and using a plate heat exchanger between the two loops?

It seems that completely isolating the two circuits is the only option left...

 

[WanderingBison]

It seems that completely isolating the two circuits is the only option left...

It’s not all bad - and with a bit of wiring and an additional pump in the engine loop to circulate coolant to pre-heat the engine (if that’s important for you to maintain) you solve your issues.


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[RAM5500 CAMPERTHING]

I'd 100% isolate the circuits.. No questions asked..

If you get a leak or failure with an isolated heater circuit, you dont have heat.. not a huge deal or emergency

If you have a leak or failure with a coolant circuit connected to the truck, you can potentially lose coolant and destroy your entire motor, a much bigger deal..

Theres at least 2 stories on here of that happening to Earthroamers and the repair cost is insane, and not a warranty item.

This is one of those things i considered very very heavily in my build and simply decided the above for the reasons mentioned.

End of the day, we all want convenience, but more often than not, we give up some of them for reliability and safety. This is one of those, IMHO

 

[Trail Talk]

If you have a leak or failure a circuit connected to the truck, you can potentially lose coolant and destroy your entire motor, a much bigger dear.. Theres at least 2 stories on here of that happening to Earthroamers and the repair cost is insane, and not a warranty item.

You've put your finger on my biggest worry with having this situation go unresolved into the summer driving season. While it typically loses less than two litres over our shorter trips, the level in the truck's reservoir drops below minimum, which I'm sure is stored for the service department to see. This 7.3L gas engine does have an enormous 21 litre capacity, however.

 

[Trail Talk]

Our Summit was at Lite Industries this week for what is hoped to be the final fix for our hydronics. Although it is a very nice 4hr round-trip drive in the country (and coming from farming roots, I really mean that), we are hoping this sixth time is the charm. The solution is simple and straightforward; the vent cap on the high-point fill tank in the cabin was replaced with a non-venting cap, leaving the only vent in the system at the truck's coolant tank. Pressure is equalized by a small-orifice venting tube between the high-point tank and the coolant overflow tank at the bottom of the system (dotted orange line). In addition, a leaking ball-valve was replaced.

As mentioned by others, the risk is that a leak anywhere in the system will affect both truck and cabin coolant levels. OTOH, truck coolant level is easily monitored and 21 litres is a lot to spill without noticing ;-)

 

[calicamper]

Small sailboat diesel heat exchanger looped into the system to separate them might be a easy fix. I can’t imagine having a vehicle cooling system tied to a camper heating system seems like a really easy way to have a cooling system failure that strands you.

 

[Joe917]

Small sailboat diesel heat exchanger looped into the system to separate them might be a easy fix. I can’t imagine having a vehicle cooling system tied to a camper heating system seems like a really easy way to have a cooling system failure that strands you.

It is common practice to tie the vehicle and camper coolant loops together. There is no reason the camper cooling loop should be any more prone to failure than the vehicle system. Shut off valves between the two circuits should be installed and easily accessible.