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livethevanlife
Samba Member
Joined: May 18, 2015
Posts: 191
Location: La Paz, Baja California Sur
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 Posted: Thu Nov 24, 2016 12:22 pm Post subject: Subaru EJ25 Thermostat Woes |
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Hey Guys, Early 2000's SOHC EJ25 motor in a Vanagon with a EMS instead of OBD. Had the motor rebuilt and installed in the spring. About a month after install, it boiled over on me while driving at a moderate speed on the freeway. I pulled over immediately before there was any serious damage. Took it to a shop where we replaced what looked like a faulty thermostat, you could see on the thermostat where it looked like it was rubbing and sticking. Replaced it with a aftermarket one from Autozone, installed it, pressure bled the coolant at a shop, and drove it home. Next day, same issue. I removed the thermostat and ran it since then without one with no cooling issues. I've deferred this long enough and am going to try to tackle this again tomorrow and see if I can figure out what's going on. This time i'm going to go to a Subaru dealer and get a OEM thermostat and try that as someone had recommended that could be a possible issue. I was just under the van taking a look at things before I try to tackle the job tomorrow and saw this blue bolt, it looks like it's an adjustment for something on the thermostat housing. Does anyone know what it is and used for? Any guesses what could be the issue if I reinstall the OEM thermostat tomorrow and it boils over again? To recap, doesn't overheat without thermostat, overheats with thermostat.
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1991 Syncro Triple Knob Westfalia "Miki" 2.2WBX
1992 Syncro Triple Knob Tintop "Schnitzel" 1.9AAZ
1990 Syncro Rear Locker Doka Subi 2.2
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davevickery
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Joined: July 16, 2005
Posts: 2887
Location: Fort Collins, CO
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| Posted: Thu Nov 24, 2016 1:46 pm Post subject: Re: Subaru EJ25 Thermostat Woes |
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I removed the jiggle pin and drill out the hole a little bit 1/8" or 3/16". Seems to flow just a bit more coolant than it would otherwise. Mine have never boiled over though. Having it out also helps a lot for it to self bleed during cool down cycles.
What size hose to you have as a bipass to the thermostat housing? Is it using the rear heater loop as a bipass, if so that needs to be left open.
I think that blue plug is just a plug maybe it went to an oil cooler. Some of the engines come with an oil cooler housing that sticks down and may not have been used on your conversion, like mine. Mine just has the hose cut and plugged.
BTW, everyone says use OE thermostat but I doubt the aftermarket one was bad out of the box. I think they are just way cheaper made but should still work initially. You could put it in a pot of water on the stove and test it. So you will probably need to figure out why you're not getting coolant through your bipass to tell the thermostat to open. |
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wcdennis
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Joined: July 20, 2004
Posts: 955
Location: Winston-Salem NC
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| Posted: Thu Nov 24, 2016 3:26 pm Post subject: Re: Subaru EJ25 Thermostat Woes |
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| Does your heater work? If so, try driving with it ON and see if that helps. Older Subarus had an always-open heater flow, that was integral to the cooling system. If your heater is not working, you may still have some air trapped in the system. Getting it all out can be a challenge. |
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wesitarz
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Joined: August 20, 2012
Posts: 1488
Location: Victoria,B.C.Canada
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| Posted: Thu Nov 24, 2016 11:37 pm Post subject: Re: Subaru EJ25 Thermostat Woes |
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Is that a stock thermostat housing/water pump? Where is the heater return line? What was there before the blue plug - a nipple? What kind of temp feedback loop do you have plumbed to the thermostat? For example this is my 02 Impreza thermostat with a feedback loop from the coolant manifold to a sandwich adapter between the WP and thermostat housing.
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syncrodoka
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Joined: December 27, 2005
Posts: 12005
Location: Santa Cruz, CA
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| Posted: Fri Nov 25, 2016 1:07 am Post subject: Re: Subaru EJ25 Thermostat Woes |
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Aftermarket thermostat issues for subarus are well documented in many enthusiast groups. Undersized, doesn't open all the way, poor flow etc are the usual complaints.
For example
That blue allen head plug in the thermostat housing likely doesn't effect anything as the spring side of the thermostat is on the water pump side not the cap side. |
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wesitarz
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Joined: August 20, 2012
Posts: 1488
Location: Victoria,B.C.Canada
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| Posted: Fri Nov 25, 2016 2:00 am Post subject: Re: Subaru EJ25 Thermostat Woes |
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| The Subaru thermostat with the jiggle pin is recommended and I believe the position of the jiggle pin appears to make a difference having it face forward (in the Subaru) so facing to the rear in the Vanagon. |
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livethevanlife
Samba Member
Joined: May 18, 2015
Posts: 191
Location: La Paz, Baja California Sur
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| Posted: Fri Nov 25, 2016 8:01 am Post subject: Re: Subaru EJ25 Thermostat Woes |
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Good suggestions guys thank you. Im calling my local subaru dealership this morning to see if they have any OEM thermostats in stock and then im going to reinstall and see what happens. Ill post back here with any issues and if its resolved.
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www.LiveTheVanLife.com
www.VentureLibre.com
https://www.PeaceVans.com/baja
1991 Syncro Triple Knob Westfalia "Miki" 2.2WBX
1992 Syncro Triple Knob Tintop "Schnitzel" 1.9AAZ
1990 Syncro Rear Locker Doka Subi 2.2
1974 VW Thing 1835cc
1989 VW Carat |
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Jake de Villiers
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Joined: October 24, 2007
Posts: 5911
Location: Tsawwassen, BC
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| Posted: Fri Nov 25, 2016 8:38 am Post subject: Re: Subaru EJ25 Thermostat Woes |
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As others have said already, you need an OEM thermostat and you also need one of Tom Shiels thermostat housings. Tom's housing provides the direct feedback circuit from the engine that keeps the temperature stable.
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http://sites.google.com/site/subyjake/mydixiedarlin%27
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dobryan
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Joined: March 24, 2006
Posts: 16501
Location: Brookeville, MD
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| Posted: Fri Nov 25, 2016 12:42 pm Post subject: Re: Subaru EJ25 Thermostat Woes |
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I would get two stock thermostats from the dealer and check them both along with your old one (if you still have it). The aftermarket thermostats are to be avoided as others said, and you should always check a new one before you put it in.
On my EJ25 I had an issue on my long summer trip where the temps would go up more than expected on hill climbs where before they were steady earlier. While staying over in Calgary I took the opportunity to replace the thermostat and compared the old one with a new one. The old one (and new) started opening at the right temp but the old one only got 50% as open as the new one when fully open. I was getting hotter than normal because it restricted the coolant flow. As has also be asked, what is the coolant system routing for your EJ25? What feedback loop is there? Many times it is set up to use the rear heater circuit and if so the valve on the rear heater must always be in the full open position. What do you have? 
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
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https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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livethevanlife
Samba Member
Joined: May 18, 2015
Posts: 191
Location: La Paz, Baja California Sur
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| Posted: Fri Nov 25, 2016 1:11 pm Post subject: Re: Subaru EJ25 Thermostat Woes |
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Hey Guys, threw the new OEM Subaru thermostat in this morning. The parts guy at the Subaru dealership even mentioned that aftermarket thermostats do not work on these motors which was interesting to hear. I tested it in boiling water before installing. Started it up, bled it for a couple hours (yes hours!), and just took it for a 10 mile test drive on back roads with no issues. The water temp stays a little higher than it would get before, 195-205, then the radiator fan comes on and it stays within that range, which is great. I'm going to go for a 20-30 mile round trip on the freeway in a little bit and see how it does, but I think i'm good. Ill try to bleed it some more after that trip in case there's any lingering air bubbles. If I run into any other issues i'll report back to this thread. In the meantime make sure you guys are using those sweet OEM Subaru thermostats in your builds  Thanks for all the help!
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www.LiveTheVanLife.com
www.VentureLibre.com
https://www.PeaceVans.com/baja
1991 Syncro Triple Knob Westfalia "Miki" 2.2WBX
1992 Syncro Triple Knob Tintop "Schnitzel" 1.9AAZ
1990 Syncro Rear Locker Doka Subi 2.2
1974 VW Thing 1835cc
1989 VW Carat |
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dobryan
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Location: Brookeville, MD
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livethevanlife
Samba Member
Joined: May 18, 2015
Posts: 191
Location: La Paz, Baja California Sur
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| Posted: Fri Nov 25, 2016 1:30 pm Post subject: Re: Subaru EJ25 Thermostat Woes |
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I don't have a bypass. But otherwise it's the same as the cooling diagram by small car. Radiator return line goes to bottom of thermostat housing, heater return line returns to above thermostat. From coolant manifold one side goes out to radiator and the other side goes out to heater core. The coolant expansion tank is T'd into both of the heater lines.
_________________
www.LiveTheVanLife.com
www.VentureLibre.com
https://www.PeaceVans.com/baja
1991 Syncro Triple Knob Westfalia "Miki" 2.2WBX
1992 Syncro Triple Knob Tintop "Schnitzel" 1.9AAZ
1990 Syncro Rear Locker Doka Subi 2.2
1974 VW Thing 1835cc
1989 VW Carat |
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dobryan
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Location: Brookeville, MD
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livethevanlife
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Location: La Paz, Baja California Sur
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| Posted: Fri Nov 25, 2016 9:08 pm Post subject: Re: Subaru EJ25 Thermostat Woes |
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It was pretty warm out today and I didn't have the heater on, seemed to work fine with no issues, did about 10 miles of around town driving and another 40 or so on the freeway at 65-70mph. Was about 80 degrees out. Didn't go up any crazy grades or anything super taxing, but held steady at 195-205, at 205 indicated on my water gauge the thermostat would open, and then the water would drop to 195-200 and stay there.
_________________
www.LiveTheVanLife.com
www.VentureLibre.com
https://www.PeaceVans.com/baja
1991 Syncro Triple Knob Westfalia "Miki" 2.2WBX
1992 Syncro Triple Knob Tintop "Schnitzel" 1.9AAZ
1990 Syncro Rear Locker Doka Subi 2.2
1974 VW Thing 1835cc
1989 VW Carat |
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16501
Location: Brookeville, MD
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| Posted: Sat Nov 26, 2016 10:06 am Post subject: Re: Subaru EJ25 Thermostat Woes |
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| livethevanlife wrote: |
| It was pretty warm out today and I didn't have the heater on, seemed to work fine with no issues, did about 10 miles of around town driving and another 40 or so on the freeway at 65-70mph. Was about 80 degrees out. Didn't go up any crazy grades or anything super taxing, but held steady at 195-205, at 205 indicated on my water gauge the thermostat would open, and then the water would drop to 195-200 and stay there. |
Here is what happens when the rear heater circuit is closed. The thermostat is set to start to open at it's rated temp. The idea is that this is the is the temp of the coolant in the manifold of the engine. But when you run that coolant up through a long run of feedback loop it cools down on its own and by the time that coolant feedback is at the temp to start to open the thermostat the actual coolant temp at the manifold is much greater. My coolant temps run in the 180's under the same scenario you have. Freeway driving at 100 degrees outside is still at 190. The only time I have elevated coolant temps (up to 202) is in stop and go traffic, or climbing a major incline in 2nd or 3rd. If I was in your situation (and I have been) I would strongly consider this...
http://www.thesamba.com/vw/forum/viewtopic.php?t=522274&highlight=shiels
Some think it is not necessary but I like it a lot. YMMV.
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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davevickery
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Joined: July 16, 2005
Posts: 2887
Location: Fort Collins, CO
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| Posted: Sat Nov 26, 2016 11:48 am Post subject: Re: Subaru EJ25 Thermostat Woes |
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That first drive isn't a good test of the temps though because there can still be a little air in the system. After a couple cool down cycles it should be fully purged.
| dobryan wrote: |
| ... But when you run that coolant up through a long run of feedback loop it cools down on its own and by the time that coolant feedback is at the temp to start to open the thermostat the actual coolant temp at the manifold is much greater. |
This is the reason I remove the jiggle pin and drill out the hole slightly. I don't hear others talking about it but it seems to help. It does take slightly longer for the engine to fully warm up and going down long grades the temp will go lower than it would before but it seems like a good compromise. It certainly helps bleeding if you give it a couple heat up cool down cycles.
I like the TShiels T-stat housing but have not tried one. I recall on my first conversion (KEP) messing around with the hoses so it would bleed easier. And I also removed the jiggle pin on that van.
On my current van, the engine ran a bit warmer than the WBX (maybe 1/2 needie width so not much) but the low speed fan would come on more. It seemed to heat up more under load than the WBX did. It always maintained mid-led going down hills though and great heat output. But with AC on and running up tough grades the high speed fan would come on some times in summer. That made me think me it wasn't getting good feedback, especially since I replaced the radiator as a first step. |
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