Crankcase breather heating element questions

[Ronzo_volvo_guy]

Forum;

In studying the Wiring Diagram for our '87 Waterboxer, I note this heating element is powered any and all the time when Ignition is powered!
I have exercised the search function, found and studied this ( https://www.thesamba.com/vw/forum/viewtopic.php?t=635294 ) and see that this element should be between 4 and 17 Ohms!...that a lot of Watts (36 - 8.5W)!
I could see this for cold operation (to stop icing, similar to "carb heat"), but is it really necessary to have that powered up ALL the time? ...or is it some California emissions thing, where they don't care about electrical usage, or how much extra and unnecessary heat this causes to be generated in the engine compartment, as long as those mean old crankcase gases are properly handled? Can anyone shed some further light on the crankcase Vent system and function.

TIA!

[djkeev]

You are correct, it is on with the key.

Why?
I don't know.
In 1986 it was a late year introduction and added on after the fact. Some very early 86's may not have it yet.

The heater has a reduced orifice size.... 5.5 mm IIRC?
Anyway, I wonder if that small orifice creates a Venturi effect on the air rushing through it?

Dave
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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[Ronzo_volvo_guy]

Dave;

Thanks for response.

PCV systems typically have flow restriction through a calibrated orifice (to prevent excessive False Air), so that is not so new or unusual.

With crankcase ventilation, it's not like there is a huge flow, more like drawing away any blowby gasses, so I would not describe it as "air rushing through" so much, but if there is ANY flow, it must follow Bernoulli's Principle, and so some cooling at the limiting orifice will occur...but again, I would expect this to be pretty insignificant and incapable of "icing up" (certainly after engine warmup), and that's the reason I asked. Until I understand it better, it still seems like a waste of electrical energy and components, and a questionable source of waste heat to me...can you give any symptoms when this heater or other components of the crankcase venting system fail. Maybe I'll search for some threads on this...

Cheers

[Howesight]

The orifice in the heated PCV oricie is 7/32nds in diameter. A cold Vanagon engine in winter starting will typically have some amount of congealed milky-looking detergent gunk from the engine oil sitting in the breather plumbing.

On a Chevy or Toyota, the PCV valve is typically attached to the cam cover or valve cover and heated by the block and radiator air. In the Vanagon, this part of the PCV plumbing does not get any ambient heat from the radiator (rear engine and front rad), and there is no warming from the engine block because the breather tower is heat-insulating plastic. That orifice can easily become blocked by frozen gunk, but the heating element prevents this.

Remember the very cold environments in which this vehicle was expected to operate. In a cold engine, there is usually a significant amount of condensed water in the crankcase (from blow-by when the engine was last run) and in the PCV system - - more than enough to ice up the restrictor orifice if it were not heated.
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'86 Syncro Westy SVX

[Ronzo_volvo_guy]

How;

Thanks for a reasonable functional explanation!

Cheers

[djkeev]

You should know that your engine crankcase vent tower is most likely not functional anyway.

The rubber diaphragm in the top portion probably rotted out years ago, decades ago most likely.

The little vent hole that was an atmospheric balance for the diaphragm under the top lip now spews out oil vapor all over your engine.

There'$ been much discussion about this diaphragm, what it did, is it needed snd is it worth $80 to get s new tower that (knowing todays rubber quality) will also rot out in a few years?

Mine is rotted, when I pulled out the inner baffle assembly I could see the shredded rubber. I sealed off the tiny hole to keep my engine clean and bolted it back on.

Dave
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[DanHoug]

might not be a bad idea to put a snap action thermostat inline with these to cut out heating at a specificied temp. Senasys snap t stats can handle plenty of current, are dead reliable, made in the USA, and CHEAP!

http://senasys.com/product/2511-series-34%E2%80%B3-thermostat-switch-large-bracket-l

for those in warm climates, it may never come on, saving some pin 15 wear and tear.
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[Ronzo_volvo_guy]

Dave;

Thanks for additional info...I had seen mention of the "tower" in several threads, but haven't looked at in person yet...
The van is expected to be here today for Service and PMs, so this will be another item on our list of things to inspect. If I find it "rotted... and spewing out oil vapor", I will seriously consider loosing that (therefore useless) heating element also...

The factory had a number of variations in the PCV systems on vintage Volvos, even changing the direction of flow of the gases in the plumbing from the early carbed to the later FI engines, which causes owner uncertainty, and also has resulted in a lot of "creative owner engineering" which has been observed on these cars. At the very least, when it is not configured or functioning correctly, it can result in oil fumes and stink (I call that Open Crankcase Venting OCV!), at the worst, pressurized Crankcase resulting in oil leakage as oil gets pushed out at seals. It's not really that difficult to install a functioning system at the Goldilocks point, between those two extremes... I've documented PCV in general and specifically for the Volvos here, including info for the Bosch D-Jetronic (forerunner of the Digifant) equipped engines if anyone is interested (it's all applicable): https://www.sw-em.com/pcv_diagrams_and_notes.htm

Cheers

Edit: Dan; A reliable temp sensing switch to power/depower that heater seems like a very good idea to pursue!

[bkleysteuber]

I have a related question about the resistance of the heating pipe for the crankcase. I have been trying to find the reason that my ‘86 waterboxer will die when I come to a stop or downshift as Ii go into a turn. To that end, I checked my breather pipe/heater for possible air leaks and function of the heating element. Bentley does indicate that the resistance should be between 4-17 ohms @ 77deg F. When I checked the resistance of my unit I found that it was better than 45 ohms resistance. Since the value was high, and the ambient temp was low, I used a hair dryer and to bring the temp up. The resistance was still greater than 45 ohms.

I don’t understand how the resistance/heat is generated but it seems like a very simple system. If the previous post was concerned about 4-17 ohms, I feel that I should be very concerned about 45+.

Your thoughts would be appreciated. I would replace it if I could find another but I haven’t found one for sale.

[jlrftype7]

[brickster]

Agree with jlrftype7 that it's most likely added resistance from the ancillary wiring from age. Since these were only offered in Canada, it may be a tricky part to source.

I've never seen one in real life, but perhaps detach the connector(s) and inspect. If you see oxidized buildup instead of shiny metal, try some diluted acid or electrical cleaner to remove it.

Also, if you can measure the resistance without taking into account the loom/wiring, that would isolate the test to the heating element alone. Unless that's how you did it here?

[DanHoug]

i disconnect mine seasonally to Save the Amps off the circuit. both my US spec 87 and 89 have them, don't think it is a Canadja only deal.
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[do.dah]

[DanHoug]

nope, lazed out and just pull the plug when i'm underhood when getting warmish out. absolutely no issues running it unplugged in spring, summer, fall. winter here is a must to have it plugged in as it WILL freeze shut.
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com