I just replaced the radiator on my 95 Camry 4 cyl. I used new hoses
for the upper and lower radiator feeds and 2 new hoses for the
transmission cooler. I had a little trouble with the new transmission
cooler hoses engaging them as far onto the fitting as I would like.
The clamp is defnintly on over the bump in the fitting. I believe
these hoses are not under high pressure.
Is this correct? How much pressure is on the trany fluid that passes
through the tranny cooler hoses?
Likewise, I'm not sure about the particular car being discussed, but
when vibration against one of the clips holding it to the frame ate a
pinhole in the metal line of an 80's vintage Ford F-150, and started
spewing tranny-juice all over bottom of the driver's side exhaust
manifold one evening far from home (I thought the freakin' engine had
caught fire, the smoke was so heavy!) I found that 3-4 wraps of typical
black electrical tape was an adequate "until the parts places open in
the morning and I can get a new piece of line" repair. Ended up not
having any option but to drive it for almost 4 days before being able to
actually crawl under and fix it proper, and when I did, found that
leakage after applying the tape was close enough to zero, and the tape
showed no inclination to "blow out". So for that case, the answer is
"comparatively low". Mileage is all but certain to vary from one setup
to the next, though - I have no doubts that there are vehicles out there
running high pressure to the cooler, and that such rides would have
popped the tape almost instantly.
Don Bruder - firstname.lastname@example.org - If your "From:" address isn't on my whitelist,
or the subject of the message doesn't contain the exact text "PopperAndShadow"
I have never measured it directly, but I believe the cooler circuit
runs about 10 to 30 psi. You should be OK if the clamp is past the
tubing flare, but I can't help but wonder how you had any difficulty
replacing the hoses. The factory hoses go back on quite easily, and
new hose (of the correct ID) fits easily as well.
That said, the cooler circuit can move fluid at a high rate of volume.
If the hose pops off it won't take long to drain the sump.
Toyota MDT in MO
they were generic hoses for tranny coolers,,, they were snug and I just
didn't get them inserted as far over the flare as I would have liked,
but they are on far enough that the clamp is fully past the flare so I
should be ok, just my usual bit of paranioa after a big job...
wondering about what I may have done wrong...
The ATF is not under high pressure when it is traveling to the transmission
cooler. High pressure lines will not be held in place with a spring clamp
and are usually threaded.
The pressure going to the transmission cooler is probably under 20 PSI.
On Tue, 31 Oct 2006 18:43:02 -0600, "Ray O"
But remember that doesn't apply as a blanket rule to all cars, and
it's good that you thought to check.
As an example, on some old GM Powerglide transmissions the cooler
line pressure is low in Neutral and Drive - but it spikes to around
150-200 PSI when you shift into Reverse, and can blow cooler hoses
that aren't made to handle that much pressure.
Even at 150 PSI with 1/4" hose the hose fittings don't have to be
too special, besides having a positive retaning bump or 'arrowhead'
groove as a retainer, and the hose has to be clamped past the bump
with wide worm-drive clamps to make sure it can't come off.
(No 'wire spring' clamps, not enough clamping force.)
But when you get much higher in pressure than that, or larger hoses
that will see the effects sooner, you have to go to a mechanically
clamped hose fitting system of some sort. Notably the ones using the
Aeroquip design (or equivalent) if you want to field assemble the hose
They have a threaded mandrel 'nut' that clamps the outer sheath of
the hose into the fitting, so it can't pull out short of severe abuse
- things like a motor mount shearing and the hose tries to hold the
engine in the car...
--<< Bruce >>--
Look above (a little closer) for the answer - I snipped it down to
only the relevant bits for ease of reading comprehension. ;-)
Ray was a District Service Manager for Toyota for many years, and
went through all the same training as the line technicians...
He can't give you an exact figure, obviously, but "under 20 PSI" for
the models of transmissions offered in that vintage Camry is more than
"close enough for Gummint Work".
Any purpose-made hose that they shipped with a trans cooler kit, the
rubber compounds used can handle the fluid without deteriorating and
should be fine, they are usually rated at 100 PSI or better in those
small sizes. The hose ratings should be printed on the side of the
hose, and on the package.
You do NOT want to use regular "fuel line" or "heater hose" - that
is NOT meant for transmission fluid, and will go bad and leak/burst on
you much faster than the right hose.
--<< Bruce >>--
Actually, "under 20 PSI" is just a guess on my part, I can check a factory
service manual when I get home tonight. IIRC, the pressure going to the ATF
cooler is much lower than internal line pressures, which is how I came up
with 20 PSI.
You are correct about your pressure guestimate, the cooler circuit
pressure is regulated (reduced) in the valve body. I suspect you will
not find a spec on cooler pressure, but if you do let me know. The
only spec I have ever seen in any model/year Toyota RM is for line
pressure under various conditions.
Toyota MDT in MO
I typically only reply to rec.auto.tech but sometimes a poster will
query multiple groups so my reply and followups go to all groups
The Toyota group has really turned me off for a while now with the OT
junk and those few idiot regulars that try to ruin it for everyone. At
rec.auto.tech the idiots are easier to shoe away, or so it seems :)
Good to hear from you, Ray.
Toyota MDT in MO
Simple enough to fix - but first, you'll have to get a real
newsreader, as Google Groups doesn't offer any forms of filtering.
<cough www.forteinc.com cough>
Then you warm up the Twit Filter in the offline news reader
software, and plonk all the people who are normally way off in left
field, and wouldn't know a clue if it walked up with a name tag on and
Set the filter with a 30-60-90 day timeout if you think they may
develop a clue in time.
I have 18 entries in my filters for a.a.toyota at the moment (many
for one person) and all of the political threads that have turned into
inane shoutfests marked "Ignore", and I feel much better.
Doesn't take much to pull the Signal/Noise ratio out of the mud.
--<< Bruce >>--
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