Overheating after climbing hill - why?
Mary Ryan
long hill. At the top of the hill, the 4Runner was overheating. I stopped
the car and lifted the hood, and saw the coolant was boiling over into the
overflow tank. There was no steam cloud coming from the engine, and no
coolant leaking from anywhere, so after it cooled down I drove on to
my destination (with the heater running to help blow off the heat).
Later, when the engine was cold, I added water to the radiator and it
only needed a pint. So I assume this was not a serious overheating -
the temperature gauge has been holding steady ever since.
My 4Runner has 112K miles, and I have driven up much steeper hills than
this without overheating. What could cause this: a bad thermostat perhaps?
I had an unpleasant (and expensive) experience with overheating in my
previous car (a 1986 Subaru which blew both head gaskets after a heater
hose broke), and I don't want that to happen to my 4Runner.
(Apologies if this appears twice; I tried to post this yesterday but
I don't think it made it)
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Mary Ryan mr...@stsci.edu
Space Telescope Science Institute
Baltimore, Maryland
Jim Bruder
: On Saturday, I drove my Toyota 4Runner to Virginia, and drove up a 4 mile
===================================
Have you ever had your radiator "rodded" out? It is possible over time
for the radiator cooling passages to become clogged or for an internal
problem, such as an internal leak, to develop within the radiator. In
these cases, no coolant is lost but the effectiveness of the radiator
is severly diminished. Also, have the radiator cap checked to ensure
that it is maintaining the proper pressure for the cooling system.
Good luck.
...Jim
Todd Hutchinson
> On Saturday, I drove my Toyota 4Runner to Virginia, and drove up a 4 mile
> long hill. At the top of the hill, the 4Runner was overheating. I stopped
> the car and lifted the hood, and saw the coolant was boiling over into the
> overflow tank. There was no steam cloud coming from the engine, and no
> coolant leaking from anywhere, so after it cooled down I drove on to
> my destination (with the heater running to help blow off the heat).
> Later, when the engine was cold, I added water to the radiator and it
> only needed a pint. So I assume this was not a serious overheating -
> the temperature gauge has been holding steady ever since.
> My 4Runner has 112K miles, and I have driven up much steeper hills than
> this without overheating. What could cause this: a bad thermostat perhaps?
> I had an unpleasant (and expensive) experience with overheating in my
> previous car (a 1986 Subaru which blew both head gaskets after a heater
> hose broke), and I don't want that to happen to my 4Runner.
>
been
always using antifreeze? Have you also been using distilled water in your
radiator? If you answered no to either one or both of these questions, you
might have have you radiator rodded or re-cored.
--
Todd Hutchinson
Ron Miller
: : On Saturday, I drove my Toyota 4Runner to Virginia, and drove up a 4 mile
: : long hill. At the top of the hill, the 4Runner was overheating. I stopped
: : the car and lifted the hood, and saw the coolant was boiling over into the
: : overflow tank. There was no steam cloud coming from the engine, and no
: : coolant leaking from anywhere, so after it cooled down I drove on to
: : my destination (with the heater running to help blow off the heat).
: : Later, when the engine was cold, I added water to the radiator and it
: : only needed a pint. So I assume this was not a serious overheating -
: : the temperature gauge has been holding steady ever since.
: : My 4Runner has 112K miles, and I have driven up much steeper hills than
: : this without overheating. What could cause this: a bad thermostat perhaps?
: : I had an unpleasant (and expensive) experience with overheating in my
: : previous car (a 1986 Subaru which blew both head gaskets after a heater
: : hose broke), and I don't want that to happen to my 4Runner.
: : (Apologies if this appears twice; I tried to post this yesterday but
: : I don't think it made it)
: : ---------------------------------------------------------------------
: : Mary Ryan mr...@stsci.edu
: : Space Telescope Science Institute
: : Baltimore, Maryland
Don't overlook the simplest things.
Have the radiator cap checked for holding proper spring pressure.
(caps get tired and are a common failure)
112k miles worth of bug parts jammed into the radiator fins can
have severe consequences for cooling area available to do the job.
(probably requires a blast cleaning of the radiator from the back side, or
possibly removal for cleaning)
Is the radiator fan mechanism working properly? (electric fan or mechanical,
they should be helping move some air)
A stuck thermostat should show up some misbehavior on the temp guage
(if there is one). Thermostats can, and will, stick in intermediate
positions. (not just OPEN or SHUT) If no temp guage, changing the
thermostat is, in most vehicles, not very difficult.
If you've been getting regular coolant flush & refills, have your shop
go over the above points. If you've never had the coolant flushed,
there may be some more difficult problems.
BTW- Shutting off the engine immediately following a long, hard pull is not
the best of practices. If my engine were overheating but not blowing
big steam, under the circumstances, I'd pull over, pop the hood open,
turn up the heater & heater fan, and hold my throttle at a fast idle
to see if the temp will come down. You want to shut down at a
temperature stabilized condition if possible.
Ron Miller
Jon Borman
at 112,000 miles, any vehical that you want to keep, i would get the
radiator rodded and replace the therm - with a dealership item only. do
this just on principal because an ounce of prevention is worth a gallon of
...
rodding the radiator, here if you do it yourself costs only $50.00. its
cheaper to do that than wait until the thing overheats and youve got a
blown head-gasket, or worse. also check the water-pump, timing, etc.
did you consider elevation of the mountain as a possible cause of the
overheating ???