Look what I found! (rear heater content)

[Crughy]

I know Ben of Benplace's found one on an engine once. Just to fill a plug. I can't remember, I don't think it was for the oil drain. but something as weird.

They can do a nice job anywhere on a van...

JP

[McVanagon]

[floggingmolly]

[PDXWesty]

If you really don't want to spend the $75 to replace the core, I would try and leave it so the next owner could do so if they wanted. I would simply plug the hoses behind the fire wall and save the heater core for the next owner.

[floggingmolly]

Agreed. Far too many people toss the original equipment, and it can very very difficult or expensive to replace. I've got mine in the garage.
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'85 Wolfsburg Weekender

[tencentlife]

WT is right about the layout. The rear heater and front heater cores are parallel branches of one long single heater loop off the engine cooling system. It receives flow under all engine conditions, warm or cold, if either or both of the valves are open, and you regulate the flow manually with the control valves. If you short-shunt (connect together) the rear heater hoses, that makes an clear, short, and easy path for the heater flow to return to the engine. That will rob the forward heater core of a good part of its flow, since it is further from the motor and presents plenty of restriction to flow compared to an open line. That's not likely to be a problem for our warm-weather friends; if you didn't need the rear heater, you probably wouldn't notice the loss of performance from the front, either, since you probably rarely use that either.

I don't agree that short-shunting the rear heater would have any effect on overall cooling efficiency, though. It has already been shown to me that there is more than adequate flow throughout the system, even at idle, if there isn't a bunch of air trapped at the top of the radiator. When the air is all bled out, the entire cooling system becomes a closed-loop dynamic head system. It takes very very little effort to create active circulation in such a system, and an open-impeller pump will increase flow depending on how little resistance to flow there is in the loop. If there is air trapped, or restriction in the radiator, there will be lowered flow volume under all conditions, and in a system with those deficiencies I doubt that short-shunting the rear heater loop would have any measurable effect as the extra flow volume would just be potential volume that wasn't allowed to flow when the rear heater was there to presenting restriction. The only functional loss would be in the flow delivered to the front heater. The reason that is so is because the open shunt is only slightly smaller than the main heater feeds from and back to the engine.

So, if you're of a mind to remove the rear heater, but would like to use the front from time to time (defrost is a very good thing, in my opinion), then block the rear heater hoses. The fix with the spark plugs is actually a reasonable solution; try finding two 14mm bolts around to use as plugs and you might find that those old spark plugs are your only option without a trip to the hardware to buy some short 5/8" bolts or copper plumbing plugs.

If you don't care about any heat and never see the need for quick windshield defogging (and I'd like to know where you live where you have that luxury, because we need it often enough here in the high desert!), then by all means, loop the rear heater hoses together. Hell you could just remove one feed hose from its tee underneath the car and loop it back to the return for that matter. It won't impact your overall cooling efficiency. If your cooling is already bad, it won't make it any worse.
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[Jamos]

thanks for comments 10c...
after reading some of this thread, I have a better understanding of how the system/flow works.

Just to clarify my situation, my system has bled out just fine and I have no issues with heat up front. I don't use it often, but the defrost is indeed nice to have as well as some heat on my feet at night since I choose to wear sandals/flip flops a lot.


I tightened up the hose clamps around those spark plugs, and they haven't leaked a drop. I pushed them back through their holes a bit, put a support between them, and then a zip tie to snug them in place.
The heater and cover are now sitting in storage, and the extra room under the seat is fantastic. I do have to be aware not to let anything I put under there push on the hoses too much, but it's not really a big deal.
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'86 Wolfy Westy Weekender
2020 Audi Q5

[floggingmolly]

Thanks 10c. Great info as usual.
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'85 Wolfsburg Weekender

[faretheewell]

thanks 10cent.

I will be plugging my hoses while i await new heater core. Because in my neck of the woods, its cold, and that heater is clutch.

[GrindGarage]

Goy my van with the heater long gone. Wish it wash there love to take snowboard trips up to vt and thats gotta be a good boot warmer!

The van started to overheat when the temps got below 15deg. I have been spending some time now replacing all the hoses, rad, fan switch. I also have a new thermostat and water pump. I have been toying with the idea that the high flow back there hasn't allowed the thermostat to open at low speeds. the only time it would overheat is after a long trip on the highway 2hrs heading into traffic.

I guess its time to remove the coupler and put in the spark plugs.
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-cliff

91 Vanagon AUTO
97 Single Port EJ22 all smallcar.com

[sbbfuk]

I know this is an old thread but here goes.
I was planning on installing a rear heater into my Atlantic along side the eber heater, to use whilst driving to get extra heat into the rear of the van for the little one, but after reading this I'm not to sure now.
Are these heaters problematic??? or do they go on for years if looked after.

Someone did suggest driving with the eber on! can this be done and is it OK too?? as this would save me a lot of work plus I don't have to drive any holes.

Cheers
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My bus is the muts nuts

[Bruce Wayne]

first trip we took with the van after I bought it,the rear heater leaked all over the place. pulled it out in the campground and plugged the hoses. replaced all the hoses a couple of years ago and it hasn't leaked a drop. doesn't get that cold here to justify repairing it and putting it back in,plus it's only me and Mrs. Wayne that ever ride in it and the front heater is plenty. the extra storage is great too.

[Wildthings]

Just buy one of these

http://msrheaters.com/1hiout.html

[bread geek]

so just looping them together under the seat is a bad idea???cooling problems may occur???maybe my coolant light issue??

[Wildthings]

[dumptdeluxe]

My '88 had the exact same thing when I checked under the seat for the first time. Spark plugs plugging those heater hoses. They had no clamps whatsoever, but did not leak at all. Too bad the rear core was previously bad (hence the disconnection) and caused significant rusting on the floor, which has caused the exterior seams to show rusting now Replaced the rear core, cleaned and reassembled the fan, and reattached hoses. Scrubbed carpet a dozen times and put all back together. All is well and dry now, but the rusty outside seams show trauma from her history
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'65 Notch S
'85 Vanagon GL
'16 Tiguan TSi

[chojinchef]

[Team WorldTour]

FWIW- I have a BRAND NEW rear heater at my mothers house in Santa Cruz. I pulled it out of the '90 Carat this summer. I guess my brother swapped it out some time ago, and we never use it. If anyone wants it, PM me...
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1990 Feldjäger Syncro AAZ
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H6 Subaru Engine Swap Thread
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"Where am I going? And what am I doing in this handbasket?" -Nicodemus Jordan
When All Else Fails: Lather, Rinse, Repeat!

[timbo]

How was your fuel economy with only 2 spark plugs connected?
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1988 Vanagon GL/ 1991 2.2 Subie power
"Never tell a lie and you'll never have to play dumb" Anthony Kiedis

[73thingsale]

So, I have read lots of threads about pulling the rear heater, or temporarily plugging the hoses. I believe I read that the end that attaches to the rear heater is 5/8". I had seen a couple of notes about the spark plug being a good fit, and now I've seen a picture, as well as a dry erase marker, and rumors of an AA battery ( which I also thought about briefly until I talked myself out of it for fear of the battery exploding due to the heat.)

My question then is this: If I just wanted to plug the two heater hoses for a week while I wait on my new core and valve and O-ring to show up, what's the BEST and EASILY OBTAINED plug?

I don't really like the spark plug or 5/8 Bolt because the threads seem like a great way to have fluid drip under pressure, which I already had with the core. Or if I clamp down real tight on the hose at the threads maybe it cuts into my expensive VW hose. Although I noted that the original pic in this thread showed TWO clamps on each hose with the spark plug.

Any other ideas for things that have a smooth circumference that are 5/8"?
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Dave
86 GL Hardtop Blue