Another engine pre-heat blow-out

[DonnaB]

When we arrived here 10 days ago, while setting up, Don found anti-freeze all over the basement. It was quite the mess. Fortunately most of our stuff is in plastic bins, but any cardboard (that case of wine) holding stuff was disintegrating. Lots of stuff had to be cleaned off and re-packed.

It seems that even though we ordered this coach with the AquaHot, but without the engine pre-heat, Newmar connects hoses for the engine pre-heat on all diesel hydronic systems (at least those built around when ours was). If you order the pre-heat option then they also install a pump at the AH to pump the heated fluid back to the engine. We sure wish we had known then as we would have specified, NO pre-heat hose installation.

Newmar used the same hose type that Spartan used for the heater loop. The difference being that we’ve used the dash heater maybe a dozen times since being in the coach from April 2007 and the heat pressure apparently aren’t there unless that flow is opened. The engine pre-heat loop to the AquaHot/HydroHot is “in use” every time the engine is on. The heat and pressure causing the hose breakdown. There are better hoses. We’ve discovered we have a friend that had a similar thing happen, but it took out his inverter. This did spray our inverter, but wasn’t a “direct hit” so it still seems to be working fine. Another person wrote to us that their friend had the same thing happen but the inverter caught fire and the MH was a total loss, so this isn’t an insignificant problem.

We were not able to find anyone who wanted to work on this at our site, so Don added anti-freeze and made a closed loop at the back of the AH, then clamped off the pre-heat hoses from the engine. At the engine there are 2 valves (look like water faucets), but the one he could reach would just spin and not cut off. After driving the coach to a local fixit place, the guy showed him how that type of valve is “fixed” when spinning like that by completely backing it out then retightening. He wishes he had known that before. They had the valves turned off within a few minutes and not too much damage to our pocketbook. If you want the pre-heat option maintained, then the fix is certainly more involved and would be more expensive. But for us, we don’t plan to spend much time in weather requiring that and we have a block heater if the need arises. We have much more peace of mind without those hoses running thru the basement.

This is just a heads up. We've read of others with this problem, but never really had a real appreciation of it and truly, thought we were immune since we didn't order that option. I'm signing off with a word to the wise.....check your hoses

[alan1]

Look at my thread Hydro-Hot Hose Bursting

[Iron Man]

The Auqahot is installed inline with the heater hoses that goes to the dash heater. I don't know if Newmar offers the Aquahot preheat option. On 2007 models Spartan/Newmar had some issues with sections of heater hoses developing "pin hole" leaks.

[DonnaB]

Ironman,

We don't have an Essex, but can't believe this part is installed differently. The Cummins engine comes with 4 barbs off the engine, 2 with cutoff valves. Assume they are ordered by someone that way. The 2 cutoff valves are for the AH and the other 2 are for the heater loop. The heater loop is installed by Spartan and runs down the frame rail. Those hoses are enclosed and tied down and would be a bear to get out if/when they fail. Don has already said he will install a conduit underneath and run new hoses if that happens.

The AH connection to the engine is two hoses in & out that runs from those cutoff valves to the in & out ports on the back of the AH. There are distinctly 4 hoses that we are concerned with.

Yeah, I wish our would have been a pin hole . It is a 1 inch split and obviously failed suddenly. When our coach was built there was the pre-heat option (which we didn't take), but the problem is that they put in the hoses anyway. Newer models may not have that option, I haven't checked lately.

[alan1]

Why not have Newmar do the repair? They will be doing mine in may on a goodwill basis. See my thread posted above. Leave the two valves closed and go.

[DonnaB]

Well, the repair is actually done. We never wanted the option and the hoses and they are now out of the picture. We have sent off a letter of complaint to Newmar to let them know of this issue with our coach (aside from the several conversations we've had lately with tech support). Felt it was important they have a feel for how many it happens to. We had a couple of other complaints to get off our chest in areas where they cheaped out or had poor quality. Case in point...when working on this issue, found 2 other water hoses rubbing on bare metal. Both had some wear apparent so it was only a matter of time. Took pictures of them both and forwarded to Newmar. Both hoses were a result of poor quality control & follow-up on the build.

[alan1]

I noticed the same thing. The hoses should have been covered with wire loom everywhere, as they are in some places.

[footdoc]

I had heard about a batch of 06 units blowing out and was worried about it...called Newmar and was told my series..unit 9033xx had different hose. No problems YET..25K miles...might have just jinxed myself!!

[Cruzer]

Up until mid-2007 Tiffin did not utilize the engine preheat feature. After that they included it as standard. But even in the earlier models they did run the hoses. Those hoses work in either direction. If you have the preheat pump it pumps engine coolant that is heated bythe boiler to the engine and recirculates it back to the AquaHot boiler. If not, the coolant flow is in the reverse direction while driving. Your engine's water pump pumps hot coolant to the AquaHot boiler to provide some free heat to keep your boiler hot when driving. This is referred to as the MotorAide feature and is the recommended installation by AquaHot. That's undoubtedly why Newmar still ran those heater hoses to yuor AquaHot boiler, so that the Motoraide feature would work. OUr Bus came that way but I ordered the preheat pump and switch from AquaHot and added it. I do use it because it's faster than the electric block heater and works when boondocking as well. Then again, I live up in the frozen tundra while most normal RV owners don't.

[Chickadee]

Donna:

Experienced same hose blow out and coolant puddle in basement bay on our previous 06 Mtn. Aire back in 07. Investigated cause and notified Newmar about defective hose running between engine and AquaHot (cross section of hose at blow out location revealed absence of most hose reinforcement cords which are normally imbedded in the wall of such hose....even sent sample to Nappanee).

We replaced all such hose with top grade hose lines....but, of course then it was still under warranty.

Steve