Anyone bypass engine coolant water heater?

RKL · 10-02-2009, 02:15 PM

My Journey Water heater has the engine coolant heating loop in it but the it is going on 8 years old. Planning a western trip next summer with lots of mountains and was wondering if it would be wise to uncouple the coolant lines from the heater, splice them together and bypass the waterheater completely.

If the internal tubing ruptured because of age and corrosion, I don't want to be pulling a mountain pass with anti freeze spraying back into the engine area before I got a low coolant alarm...Not worried about giving up immediate hot water when we stop at nite.

I don't know if the coolant loop runs in the water heater thru the water area or loops around the outside of the heater. If it is inside in the water area I assume coolant would enter the water heater and mix with the water in the system....either case is not good. I guess if you have the motor aide option of rear bedroom heat using a coolant loop, the same possibe risk would hold true....thanks for any input that I recieve....RKL

AFChap · 10-02-2009, 03:13 PM

The "motor aid" loop is a metal loop on the outside of the tank that runs in a "U" shape on the outside surface of the rear of the tank kind of around the bottom half of the circular water tank from one side of the tank from the other. After having seen it on mine, I have no worries at all about the loop leaking due to corrosion. Unless you have replaced them all your coolant hoses (which I have not) I would be much more concerned about coolant hoses leaking than about the metal loop on the water heater tank. Personally, I think what you are proposing would be a lot of trouble for no gain.

hemidude13 · 10-02-2009, 05:03 PM

hi you do know that having the motoraid system and the rear heater doubles the coolant capacity of the coolant system,meaning a cooler running motor!

AFChap · 10-02-2009, 08:28 PM

hemidude

Welcome to the list.

The Winnebago diesels have the motoraid heat on the water heater, but DO NOT have the rear heater that runs off engine coolant. And I have to say there is no way in the world that just the motoraid heat on the water heater doubles the coolant capacity on our diesels. All it amounts to is several extra feet of heater hose. Mine has around 48 qt of coolant in the system. And if someone simply removed the hoses from the metal tube on the back of the water heater, and joined them together, that might remove 12-18" of length at the most.

Maybe all the additional heater hoses from the engine in the front to the rear of the coach and back MIGHT double it on a gasser ...are you quoting info from some chassis mfg?

Izzyblueye · 10-03-2009, 05:16 AM

Quote:

Originally Posted by RKL

My Journey Water heater has the engine coolant heating loop in it but the it is going on 8 years old. Planning a western trip next summer with lots of mountains and was wondering if it would be wise to uncouple the coolant lines from the heater, splice them together and bypass the waterheater completely.

If the internal tubing ruptured because of age and corrosion, I don't want to be pulling a mountain pass with anti freeze spraying back into the engine area before I got a low coolant alarm...Not worried about giving up immediate hot water when we stop at nite.

I don't know if the coolant loop runs in the water heater thru the water area or loops around the outside of the heater. If it is inside in the water area I assume coolant would enter the water heater and mix with the water in the system....either case is not good. I guess if you have the motor aide option of rear bedroom heat using a coolant loop, the same possibe risk would hold true....thanks for any input that I recieve....RKL

Couldn't you just install a gate valve at the start of the loop? You could then turn it off if you wanted to or if a problem did arise. If you are concerned about old hoses, I would get them replaced for peace of mind.

Chief · 10-03-2009, 08:02 AM

It can happen. Had a leak occur in the motoraid loop in our previous rig (96 Vectra, gasoline engine). Luckily I had enough parts that I simply disconnected the loop for the run into Ft Benning from south of Atlanta. Since then I have carried several hose size splice adapters along with a short section of "heater" hose. That being said, if it were to happen again I probably wouldn't have the right equipment for a temporary repair,(Murphy seems to show up during these times), but it makes me feel better.

As the Chaplain indicated above, all rubber hoses would be just as likely to fail as the short hoses connecting the motor-aid loop. For true peace of mind you would have to change out all the rubber coolant hoses. Not sure what the useful life of these hoses are but my old 92 ford pickup still has the factory hoses on it. Looks like it is about time to change to change them out. Good luck whatever you decide to do.

hemidude13 · 10-03-2009, 01:34 PM

yes sir, it was the gasser i was talking about!

RoadRohrers · 10-07-2009, 08:36 AM

I installed a manual heater shut-off valve in the coolant line to the motoraid heater. I was getting too much residual heat. Now when I want the heat, I just slide the doghouse (gas model mh), open the valve and am toasty. When I don't want the heat, I reverse the process. Very pleased with the results. If I were more ambitious, I would upgrade valve to one with a cable pull so did not have to move doghouse.

dirko · 10-11-2009, 11:18 AM

Hi Ho: As you point out we have mountains here in the west. One reason for the motoraid is to provide additional cooling for the engine. I agree with Paul that the best approach is to leave things alone. We recently drove to northern Washington where there is a long (maybe 20 minutes) of 8 percent grade. Since I am still getting used to having a good way to monitor both engine and transmission temperature I just left the cruise control on. The engine was putting out about 240 hp with the tach at about 4500 rpm. Both the engine and transmission were at about 194 deg. F. I have never had a motorhome that would keep its cool with such a long hard load. I love the motoraid. By the way, we had lots of nice hot water when we stopped.

Dirk