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SCM Samba Member
Joined: January 26, 2011 Posts: 3102 Location: Bozeman MT
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Posted: Thu Jul 20, 2017 8:43 am Post subject: Why would ATF cooler hoses melt? |
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My mechanic and the rebuilder are working diligently on it so I don't want to drag anyone through the mud here.
That said, I have a "Go Westy style" ATF cooler on my recently rebuilt auto trans. The first cooler had a small leak at a bad weld opposite the side where the hoses enter. A new cooler was sent and that one leaked worse than the first one. A third cooler was installed and all seemed ok except I noticed a small seep of ATF at the threaded connections to the cooler.
While checking that seep after a drive (16 mile highway ending with 7 mile dirt road climb in 90F temperatures) I noticed that the yellow rings at the end of each hose to the thermostat housing had melted AND the blue hoses themselves had started to crack and were backing off of the fittings.
My mechanic and the rebuilder had never seen this before and are now running diagnostics to figure out what's going on.
Any ideas? Could the cooler etc. have a blockage? _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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jberger Samba Member
Joined: November 17, 2003 Posts: 2476
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Posted: Thu Jul 20, 2017 9:33 am Post subject: Re: Why would ATF cooler hoses melt? |
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I have experienced this on an oil cooler set up. I think it is normal for the plastic ends and the hoses to "melt" and shrink. Mine did not leak, but I ended up replacing the hoses with higher end SS braided units rated for higher temps.
J |
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SCM Samba Member
Joined: January 26, 2011 Posts: 3102 Location: Bozeman MT
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Posted: Thu Jul 20, 2017 9:38 am Post subject: Re: Why would ATF cooler hoses melt? |
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jberger wrote: |
I have experienced this on an oil cooler set up. I think it is normal for the plastic ends and the hoses to "melt" and shrink. Mine did not leak, but I ended up replacing the hoses with higher end SS braided units rated for higher temps.
J |
I don't mean "melt", I mean MELT. The yellow plastic ends melted to the point of falling off completely, but only at the thermostat housing. They looked fine elsewhere. _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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jberger Samba Member
Joined: November 17, 2003 Posts: 2476
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Posted: Thu Jul 20, 2017 10:46 am Post subject: Re: Why would ATF cooler hoses melt? |
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SCM wrote: |
jberger wrote: |
I have experienced this on an oil cooler set up. I think it is normal for the plastic ends and the hoses to "melt" and shrink. Mine did not leak, but I ended up replacing the hoses with higher end SS braided units rated for higher temps.
J |
I don't mean "melt", I mean MELT. The yellow plastic ends melted to the point of falling off completely, but only at the thermostat housing. They looked fine elsewhere. |
How close were they to the exhaust manifold? |
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SCM Samba Member
Joined: January 26, 2011 Posts: 3102 Location: Bozeman MT
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Posted: Thu Jul 20, 2017 11:09 am Post subject: Re: Why would ATF cooler hoses melt? |
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jberger wrote: |
How close were they to the exhaust manifold? |
About 3 feet in front. Near, and inboard, the Westy fresh water drain. _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22568 Location: NYC/Upstate/ROW
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Posted: Thu Jul 20, 2017 11:21 am Post subject: Re: Why would ATF cooler hoses melt? |
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ATF Temps are well under thermoplastic limits. Something is badly wrong here. _________________ .ssS! |
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SCM Samba Member
Joined: January 26, 2011 Posts: 3102 Location: Bozeman MT
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Posted: Thu Jul 20, 2017 1:03 pm Post subject: Re: Why would ATF cooler hoses melt? |
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Abscate wrote: |
ATF Temps are well under thermoplastic limits. Something is badly wrong here. |
Wonderful. I'm glad it's under warranty. I'll report back when it's figured out. _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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AtlasShrugged Samba Member
Joined: October 30, 2008 Posts: 1605 Location: Decatur, Ga. USA
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Posted: Thu Jul 20, 2017 1:31 pm Post subject: Re: Why would ATF cooler hoses melt? |
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That kit has a thermostatic by-pass? Hoses melt on the hot side of the thermostatic by-pass or where?
Could be a bad by-pass? |
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SCM Samba Member
Joined: January 26, 2011 Posts: 3102 Location: Bozeman MT
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Posted: Thu Jul 20, 2017 1:46 pm Post subject: Re: Why would ATF cooler hoses melt? |
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AtlasShrugged wrote: |
That kit has a thermostatic by-pass? Hoses melt on the hot side of the thermostatic by-pass or where?
Could be a bad by-pass? |
They melted on both sides of the bypass but not at the cooler.
I wonder if the bypass was stuck closed and the hot fluid heated up the housing enough to conduct heat through the housing to melt all four hoses connected to it? That still doesn't sound right considering what Abscate said about ATF temps. And if the bypass was closed, how would hot fluid even move to it?
Not sure why I wouldn't have also seen damage at the transaxle - come to think of it, I actually didn't look very closely at that.
I wish I took a picture but I was just too pissed off to think about it beyond, "let's get it back to the shop. Again". _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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AtlasShrugged Samba Member
Joined: October 30, 2008 Posts: 1605 Location: Decatur, Ga. USA
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Posted: Thu Jul 20, 2017 2:25 pm Post subject: Re: Why would ATF cooler hoses melt? |
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I would remove the by-pass..you could make up some temporary lines then run it for awhile. See how hot it gets? An IR gun sure would be helpful.
Nothing like having your own laboratory for VW Vanagon automatic transmissions.
I doubt you damaged the transaxle..Aircooled VW Vanagons ran a close cousin of your automatic with no cooler at all..nothing.
Be sure you plumbed the hoses correctly on the by-pass...ATF flows out from the bottom port on the transmission and returns on the top port. The by-pass is marked inlet and outlet too.
Has to be the thermostatic by-pass miss connected, not working or restricted. |
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SCM Samba Member
Joined: January 26, 2011 Posts: 3102 Location: Bozeman MT
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Posted: Thu Jul 20, 2017 2:40 pm Post subject: Re: Why would ATF cooler hoses melt? |
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AtlasShrugged wrote: |
I doubt you damaged the transaxle..Aircooled VW Vanagons ran a close cousin of your automatic with no cooler at all..nothing.
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That's good to know as it's all I'm really concerned about. Like I mentioned, I'm not doing this work - for exactly this reason (labor/parts warranty) among some others.
Frankly, I would LOVE to be camping out of a tent and our brand new VW Alltrack this summer but my wife has become completely spoiled with the comforts of the Westy and hasn't bought into that idea. _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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wesitarz Samba Member
Joined: August 20, 2012 Posts: 1477 Location: Victoria,B.C.Canada
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Posted: Thu Jul 20, 2017 2:43 pm Post subject: Re: Why would ATF cooler hoses melt? |
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Is the direction of flow correct. That looks like a Derale thermostat like I have in my engine oil cooler setup. It took me a while to figure out the correct flow from the Derale diagrams and I marked it with IN/OUT and to/from cooler. Bottom fitting is OUT from the trans. I have a simple cooler with no thermostat mounted in front of the rad since 2003 Subaru conversion. With a recent inline temp sensor and gauge I have seen temps only up to about 140 F,but I haven't pushed it in the mountains yet. |
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Gizmoman Samba Member
Joined: September 10, 2011 Posts: 1554 Location: Nevada
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Posted: Thu Jul 20, 2017 3:23 pm Post subject: Re: Why would ATF cooler hoses melt? |
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No expert but I do know that hydraulic fluid (ATF) when pushed at high pressure through a restriction can easily get hot enough to melt thermoplastic hose. That said, it typically also makes quite a squeal. _________________ 82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale). |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32432 Location: Reading Pennsylvania
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SCM Samba Member
Joined: January 26, 2011 Posts: 3102 Location: Bozeman MT
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Posted: Wed Jul 26, 2017 2:31 pm Post subject: Re: Why would ATF cooler hoses melt? |
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Not much of an update but;
My mechanic can't reproduce the problem. The temps at all connections are OK. They confirmed the thermo-bypass is opening correctly. They haven't driven it as hard as I was (they didn't climb any hills with it) so they were going to beat on it a bit harder later today.
The rebuilder says that the tranny couldn't be the problem because it would have died catastrophically had it been producing temps high enough to melt things.
I think they may tell me to "just keep an eye on it", which isn't exactly confidence inspiring. _________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9517 Location: Western WA
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Posted: Wed Jul 26, 2017 2:40 pm Post subject: Re: Why would ATF cooler hoses melt? |
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need pics of the melted stuff _________________
'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb |
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scubaseas Samba Member
Joined: May 24, 2013 Posts: 442 Location: ME & Texas, in a Bus or on a boat somewhere
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Posted: Wed Jul 26, 2017 2:54 pm Post subject: Re: Why would ATF cooler hoses melt? |
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X2 on take the thermostat out of the equation. Sounds like restriction at t-stat. t-stat sticking or t-stat not hooked up right. Too cold trans oil will do little or no damage. Oil hot enough to melt plastic will eventually prove to be very expensive. Your tranny rebuilder sounds right _________________ Al
08/1970 T2a Westphalia owned since 1980
ASE Master certification. 50 years pushing a wrench
Retired |
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kourt Samba Member
Joined: August 13, 2013 Posts: 1922 Location: Austin, TX
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Posted: Wed Jul 26, 2017 3:08 pm Post subject: Re: Why would ATF cooler hoses melt? |
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I remember when I had a GW ATF cooler that the thermostat installation instructions were backwards from the Derale recommendations. You might check that. The Derale instructions are here:
http://derale.com/images/stories/virtuemart/product/pdfs/13011.pdf
You could eliminate the issue of plastics by building your own AN-6 hoses in braided stainless steel. I have some example parts for that build listed here:
https://www.thesamba.com/vw/forum/viewtopic.php?p=7512055#7512055
I drive a very heavy Westy automatic throughout the summer driving through mountain passes and on highways at 75MPH. My transmission gets hot--usually around 180F to 200F coming out of the transmission--but the fan driven cooler manages it well and my lines show no signs of heat damage.
kourt
Last edited by kourt on Wed Jul 26, 2017 3:11 pm; edited 1 time in total |
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SCM Samba Member
Joined: January 26, 2011 Posts: 3102 Location: Bozeman MT
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Posted: Wed Jul 26, 2017 3:08 pm Post subject: Re: Why would ATF cooler hoses melt? |
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Sodo wrote: |
need pics of the melted stuff |
Well, that's something I do not have. But, see the little yellow rings at the end of each hose in the photo below? Of the 4 on the thermostat housing, one had come completely off and he other three had become oval shaped and close to breaking off.
One hose, that I recall, had about a 1/8" crack on the end where it attached to the t-stat housing and all four hoses appeared to have backed off of the fittings, but not enough to expose the barb. I thought they had been tight against the housing.
My mechanic is convinced something it wrong, the rebuilder seems to think I parked over a campfire or something.
_________________ '91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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jberger Samba Member
Joined: November 17, 2003 Posts: 2476
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Posted: Wed Jul 26, 2017 8:59 pm Post subject: Re: Why would ATF cooler hoses melt? |
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Were the hoses actually leaking? You may ask volks that have had the blue hoses installed with engine oil cooler kits. I think they have been problematic. Just trying to save you a wild goose chase. The yellow collars melt and fall away and the hoses shrink and crack. |
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