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wesitarz Samba Member
Joined: August 20, 2012 Posts: 1490 Location: Victoria,B.C.Canada
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Posted: Thu Apr 29, 2021 5:22 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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wesitarz wrote: |
Look for a hot coolant feedback loop to the heater return hose or a sandwich type adapter at the thermostat connected to hot coolant return or there may be an extra nipple on the thermostat housing acting as a hot return to the thermostat. |
Edit: extra return nipple on the water pump (not the thermostat housing) in addition to the heater return
Edit: Also, Smallcar modifies the solid black heater return pipe for hot coolant feedback directly from the coolant manifold. (this would be in the area behind the A/C compressor) |
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harvgwen Samba Member
Joined: February 11, 2021 Posts: 160 Location: British Columbia, Canada
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Posted: Sun May 02, 2021 9:19 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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The engine cooling issue doesn’t seem to be just with the Subaru conversion into a Vanagon. There is quite a bit of discussion on this issue on Subaru forums as well (in Subaru cars). The problem is that there needs to be a way to keep coolant on the top side of the T-stat. As long as you have coolant flowing through your heater circuit, with no air locks, you will keep coolant flowing to the top of the T-stat, allowing it to properly sense the coolant temp, and all should be happy. I ended up drilling 2 1/8” holes in my T-stat. Now in theory (and it seems to work) I can have the front and rear heaters both turned off and the T-stat seems to work.
I haven’t had the van that long, so I’m definitely no expert. Hopefully this info can be helpful to someone else. Also, quite a few of you have years of experience with this and can correct my limited understanding of the issue. _________________ 1986 Westfalia Vanagon, 2.2 Subaru
British Columbia, Canada |
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physast Samba Member
Joined: December 30, 2005 Posts: 675 Location: DC
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Posted: Mon May 03, 2021 12:53 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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Still have not ventured under the van to take a look. I also want to look and see if the rear valve is on/off as I have not used it in many years. _________________ 1967 L633 VW beetle (currently being restored...slowly)
1991 Orly Blue Vanaru 2.5L |
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4Gears4Tires Samba Member
Joined: October 08, 2018 Posts: 3028 Location: MD
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Posted: Mon May 03, 2021 1:29 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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The rear on off rear heater valve is inside. Lift up the rear bench, left side. _________________ '87 Syncro
Ferric Oxyhydroxide Superleggera Edition |
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wesitarz Samba Member
Joined: August 20, 2012 Posts: 1490 Location: Victoria,B.C.Canada
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Posted: Mon May 03, 2021 2:40 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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harvgwen wrote: |
The engine cooling issue doesn’t seem to be just with the Subaru conversion into a Vanagon. There is quite a bit of discussion on this issue on Subaru forums as well (in Subaru cars). The problem is that there needs to be a way to keep coolant on the top side of the T-stat. As long as you have coolant flowing through your heater circuit, with no air locks, you will keep coolant flowing to the top of the T-stat, allowing it to properly sense the coolant temp, and all should be happy. I ended up drilling 2 1/8” holes in my T-stat. Now in theory (and it seems to work) I can have the front and rear heaters both turned off and the T-stat seems to work.
I haven’t had the van that long, so I’m definitely no expert. Hopefully this info can be helpful to someone else. Also, quite a few of you have years of experience with this and can correct my limited understanding of the issue. |
Yes, Subaru uses a heater bypass to get hot coolant to the thermostat so it will open. Some thermostats are vertical (faces up)and others are horizontal (faces back). AFAIK from the Subaru forums, the jiggle pin in the OEM Subaru thermostat either faces forward for the vertical or up for the horizontal. As for as drilling extra holes in the Subaru thermostat it's not needed AFAIK.
The vertical WP housing has an extra nipple for the oil cooler return that can be used for the hot return or there is a sandwich available. A dedicated return to the thermostat rather than a crossover in the heater lines might work better in colder climates where you want maximum heat for the cabin. Same for tapping the hot coolant directly from the manifold like Smallcar does. |
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physast Samba Member
Joined: December 30, 2005 Posts: 675 Location: DC
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Posted: Mon May 03, 2021 3:23 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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OK. I got a few minutes to take a look under the van and at the rear heater core. The pictures below show the current view of the rear heater core and the thermostat housing. It looks like the housing has a smaller hose going to it which might already be a hot return. I didn't have enough time to look where that smaller hose was going.
I also found what looks like a trans leak, but will post that in a new topic to keep this on topic.
_________________ 1967 L633 VW beetle (currently being restored...slowly)
1991 Orly Blue Vanaru 2.5L |
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physast Samba Member
Joined: December 30, 2005 Posts: 675 Location: DC
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Posted: Mon May 03, 2021 6:52 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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OK. After looking at other Subaru conversion cooling system images online it looks like the smaller hose is coming after the thermostat so is likely not the return I was thinking. _________________ 1967 L633 VW beetle (currently being restored...slowly)
1991 Orly Blue Vanaru 2.5L |
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wesitarz Samba Member
Joined: August 20, 2012 Posts: 1490 Location: Victoria,B.C.Canada
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Posted: Tue May 04, 2021 5:51 am Post subject: Re: rear heater delete question (vanaru conversion) |
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That's the heater return line to the thermostat (spring portion). Before that the heater return line is hard black pipe. In the A/C compressor area on top of the engine is where the pipe can be modified to get hot coolant feedback direct from the coolant manifold (Smallcar design). If nothing there, look for a crossover 'T'
between the hot and cold heater lines,usually near the back of the engine,but could be anywhere except above the gas tank.
If you can't find anything, then the rear heater is your feedback loop. You can put in a crossover 'T' between the heater lines (brass PEX 3/4x3/4x1/2 from Home Depot is what I've used), then delete the rear heater loop. |
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harvgwen Samba Member
Joined: February 11, 2021 Posts: 160 Location: British Columbia, Canada
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Posted: Tue May 04, 2021 12:21 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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Wesitarz, am I correct in thinking that since I have drilled the holes in the T-stat I should not need to keep a front or rear heater valve open, or have a cross-over installed? _________________ 1986 Westfalia Vanagon, 2.2 Subaru
British Columbia, Canada |
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skills@eurocarsplus Samba Peckerhead
Joined: January 01, 2007 Posts: 16865 Location: sticksville, ct.
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Posted: Tue May 04, 2021 2:55 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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harvgwen wrote: |
Wesitarz, am I correct in thinking that since I have drilled the holes in the T-stat I should not need to keep a front or rear heater valve open, or have a cross-over installed? |
NO
you will still need a feedback loop of some sort. that hole (which i agree is not needed in a properly set up system) will never flow enough to make a difference.
i have heard reports that the tom shiels adapter isn't big enough, i think it's for a 3/8 hose. many have upgraded that to a 1/2" from what i have read on various platforms.
in a subaru it's not needed as the heater core/hoses are a short run vs a vanagon. it may work ok if the rear core was always open (which is how i set up my bay window swaps) and works fine.
you have to think of the subaru design as having priority heating, as in the heat from the engine goes to the heater core first. once that can't shed the heat anymore, the thermostat starts to open and pisses in cold coolant from the rest of the system.
the t stat will open and close, open and close until the entire cooling system is up to temp. _________________
gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
Jake Raby wrote: |
Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
Brian wrote: |
Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
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harvgwen Samba Member
Joined: February 11, 2021 Posts: 160 Location: British Columbia, Canada
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Posted: Tue May 04, 2021 3:05 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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Thanks skills. I’ll need to leave the rear heater valve open all the time then. _________________ 1986 Westfalia Vanagon, 2.2 Subaru
British Columbia, Canada |
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wesitarz Samba Member
Joined: August 20, 2012 Posts: 1490 Location: Victoria,B.C.Canada
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Posted: Wed May 05, 2021 4:58 am Post subject: Re: rear heater delete question (vanaru conversion) |
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skills@eurocarsplus wrote: |
harvgwen wrote: |
Wesitarz, am I correct in thinking that since I have drilled the holes in the T-stat I should not need to keep a front or rear heater valve open, or have a cross-over installed? |
NO
you will still need a feedback loop of some sort. that hole (which i agree is not needed in a properly set up system) will never flow enough to make a difference.
i have heard reports that the tom shiels adapter isn't big enough, i think it's for a 3/8 hose. many have upgraded that to a 1/2" from what i have read on various platforms.
in a subaru it's not needed as the heater core/hoses are a short run vs a vanagon. it may work ok if the rear core was always open (which is how i set up my bay window swaps) and works fine.
you have to think of the subaru design as having priority heating, as in the heat from the engine goes to the heater core first. once that can't shed the heat anymore, the thermostat starts to open and pisses in cold coolant from the rest of the system.
the t stat will open and close, open and close until the entire cooling system is up to temp. |
3/8 effective opening at the nipple with 1/2 inch hose. I think it's enough.Some have gone bigger at the heater crossover (1/2 effective with 5/8 hose) The heater return or adapter brings hot coolant feedback to the spring side of the thermostat so it will open. Drilling holes in the thermostat,I don't think will do anything. |
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physast Samba Member
Joined: December 30, 2005 Posts: 675 Location: DC
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Posted: Sun May 09, 2021 3:08 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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I have convinced myself that I should just connect the two heater hoses together after deleting the rear heater.
- What is the best way to do this? A 5/8 90 degree?
- Should I also add another reducer since the rear heater core likely did act as a 'reducer'? _________________ 1967 L633 VW beetle (currently being restored...slowly)
1991 Orly Blue Vanaru 2.5L |
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dobryan Samba Member
Joined: March 24, 2006 Posts: 16503 Location: Brookeville, MD
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physast Samba Member
Joined: December 30, 2005 Posts: 675 Location: DC
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Posted: Sun May 09, 2021 5:25 pm Post subject: Re: rear heater delete question (vanaru conversion) |
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dobryan wrote: |
Can you contact Hans at Vanaru for guidance? |
I emailed him at the last known email I had for Hans and it bounced. I also contacted everyone from https://www.vanaru.com/ and never heard back.
I am not in a huge hurry to delete the rear heater, so have time to keep investigating. I just want to do this when I do my next coolant flush some time this year. _________________ 1967 L633 VW beetle (currently being restored...slowly)
1991 Orly Blue Vanaru 2.5L |
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physast Samba Member
Joined: December 30, 2005 Posts: 675 Location: DC
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Posted: Tue May 11, 2021 7:06 am Post subject: Re: rear heater delete question (vanaru conversion) SOLVED! |
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Solved!
Just heard from Hans. He said the conversion already has a feedback loop, but that he recommends connecting the rear heater core hose together for that little extra feedback.
I plan on replacing the plastic tees with metal ones (keeping the 1/2 inch branch), looking for 1/2inch silicone hose either molded in a 180 deg turn or enough to create a loop and connect the tee branches together.
I am going to keep the rear heater core assembly in case I want re-install. _________________ 1967 L633 VW beetle (currently being restored...slowly)
1991 Orly Blue Vanaru 2.5L |
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mdub Samba Member
Joined: February 05, 2020 Posts: 48 Location: Bellingham, WA
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Posted: Tue May 11, 2021 11:16 am Post subject: Re: rear heater delete question (vanaru conversion) SOLVED! |
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physast wrote: |
looking for 1/2inch silicone hose either molded in a 180 deg turn |
Here’s a good source for stuff like that, 180 degree ½” U section:
https://www.pegasusautoracing.com/productdetails.asp?RecID=11861 _________________ '86 Syncro / Reimo Poptop / EJ22 |
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physast Samba Member
Joined: December 30, 2005 Posts: 675 Location: DC
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Posted: Tue May 11, 2021 11:43 am Post subject: Re: rear heater delete question (vanaru conversion) SOLVED! |
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Thank you for this source. _________________ 1967 L633 VW beetle (currently being restored...slowly)
1991 Orly Blue Vanaru 2.5L |
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