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speeder
Samba Member
Joined: August 17, 2007
Posts: 18
Location: Durango, CO
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 Posted: Fri Jan 22, 2021 12:13 pm Post subject: Thermostat housing temp sensors leaking, O ring replacement, fix |
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A quick story for those of you with a thermostat housing leak. If it's coming from the temp sensors, you may not need to change the whole housing, just the O rings around the sensors.
My housing assembly was replaced about 8 years ago with the factory style plastic piece. It recently started dripping slowly around the temp 2 sensor and the temp sensor units. These units are held in the housing with a simple clip and seem to fit quite loosely for something that is under moderate pressure when the coolant heats up. They are sealed with a very basic O ring, like many german cars these days. I have worked with the same setup in my mid 2000 BMW's, where there is a plastic coolant system junction or male hose neck with a sensor plugged in the side and an O ring to seal it. Over time these rubber O rings shrink and loose their compliance.
All hoses around the tstat housing in the case of my Vanagon looked good, no cracks or signs of leaks, and felt compliant. The thermostat housing looked in good condition with no leaking areas on the body of the unit. So rather than replace the whole housing setup, I opted to jack up the van, don some clothing that I knew would get soaked with coolant, pulled the sensors out one at a time and very quickly swap the O rings with new ones. The new O rings were bit thicker, and far more flexible and compliant than the old ones, which had shrunk and become hard. Yes, I took a coolant shower. I lost about a half quart of coolant. Not sure yet if I will need to bleed the coolant system, but no prob if so.
It appears to have fixed the leak around both sensors, saving me a big job and expense.
Should I have changed the whole unit prophylactically? Sure, that would be an option. But if I get another few years out of this fix, I'll be happy. Swapping that whole housing looks like a PITA and it had been done fairly recently on my van, so I'm rolling with it.
I search the Samba all the time for this type of info. I didn't find much about this particular situation, hence the story here. Maybe I can return the favor from all of you and this will save one of you some time and money somewhere down the line. Thanks! |
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WestyWanter
Samba Member
Joined: February 15, 2017
Posts: 459
Location: San Diego
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| Posted: Fri Jan 22, 2021 12:25 pm Post subject: Re: Thermostat housing temp sensors leaking, O ring replacement, fix |
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| Where did you get the O ring? |
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speeder
Samba Member
Joined: August 17, 2007
Posts: 18
Location: Durango, CO
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| Posted: Fri Jan 22, 2021 12:40 pm Post subject: Re: Thermostat housing temp sensors leaking, O ring replacement, fix |
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Amazon. $10 for 2 shipped to me in 2 days. Auto parts store said they had it, and then showed me a random box of dry, stiff O rings when I got there. Not very useful.
Go westy sells the O rings for $1 each, but I was in a hurry to get it done.
_________________
87 Vanagon Wolfsburg Edition tin top |
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4Gears4Tires
Samba Member
Joined: October 08, 2018
Posts: 3028
Location: MD
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| Posted: Fri Jan 22, 2021 6:57 pm Post subject: Re: Thermostat housing temp sensors leaking, O ring replacement, fix |
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Any Ace hardware will have a whole cabinet of o-rings. After an o-ring and another a bit later, I went in and just bought several of every single metric size. Handy.
_________________
'87 Syncro
Ferric Oxyhydroxide Superleggera Edition |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32598
Location: Reading Pennsylvania
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Abscate
Samba Member
Joined: October 05, 2014
Posts: 22648
Location: NYC/Upstate/ROW
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| Posted: Fri Jan 22, 2021 7:37 pm Post subject: Re: Thermostat housing temp sensors leaking, O ring replacement, fix |
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It really helps if people document the size of orings with a vernier caliper
Outside diameter and thickness are needed.
If you are on the road and need an oring and know the size, you can find one at a local shop,to get you home
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.ssS! |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32598
Location: Reading Pennsylvania
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adventurious
Samba Member
Joined: June 13, 2022
Posts: 4
Location: California
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| Posted: Fri Oct 21, 2022 1:55 pm Post subject: Re: Thermostat housing temp sensors leaking, O ring replacement, fix |
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Is this the spot you’re talking about? I noticed that my van’s been slowly leaking coolant (I’m a new owner of about 3 months now). While poking around under the van this morning I noticed what looked like a bit of a loose connection on what appears to be the Temperature Sender Coolant Display (19.11 in Bentley) When I wiggled it, coolant dribbled out, as you can see in the photo.
If this is the same culprit? If so, is there any way to isolate this section and avoid the coolant shower, or is that the only way to do it?
Thank you!!!
PS: If this is the wrong piece, please let me know too!
| speeder wrote: |
A quick story for those of you with a thermostat housing leak. If it's coming from the temp sensors, you may not need to change the whole housing, just the O rings around the sensors.
My housing assembly was replaced about 8 years ago with the factory style plastic piece. It recently started dripping slowly around the temp 2 sensor and the temp sensor units. These units are held in the housing with a simple clip and seem to fit quite loosely for something that is under moderate pressure when the coolant heats up. They are sealed with a very basic O ring, like many german cars these days. I have worked with the same setup in my mid 2000 BMW's, where there is a plastic coolant system junction or male hose neck with a sensor plugged in the side and an O ring to seal it. Over time these rubber O rings shrink and loose their compliance.
All hoses around the tstat housing in the case of my Vanagon looked good, no cracks or signs of leaks, and felt compliant. The thermostat housing looked in good condition with no leaking areas on the body of the unit. So rather than replace the whole housing setup, I opted to jack up the van, don some clothing that I knew would get soaked with coolant, pulled the sensors out one at a time and very quickly swap the O rings with new ones. The new O rings were bit thicker, and far more flexible and compliant than the old ones, which had shrunk and become hard. Yes, I took a coolant shower. I lost about a half quart of coolant. Not sure yet if I will need to bleed the coolant system, but no prob if so.
It appears to have fixed the leak around both sensors, saving me a big job and expense.
Should I have changed the whole unit prophylactically? Sure, that would be an option. But if I get another few years out of this fix, I'll be happy. Swapping that whole housing looks like a PITA and it had been done fairly recently on my van, so I'm rolling with it.
I search the Samba all the time for this type of info. I didn't find much about this particular situation, hence the story here. Maybe I can return the favor from all of you and this will save one of you some time and money somewhere down the line. Thanks! |
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'91 Westy |
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