Yet another overheating problem, please

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Old 28 Apr 2004, 01:00 am   #1 (permalink)
JT
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Default Yet another overheating problem, please

My 1990 Lexus ES250 (aka Camry V6) has had an annoying but not fatal
cooling problem for a couple of years, without any significant change.

The car runs flawlessly if the outside temperature is no higher than
say the mid 80's or maybe a bit higher, but when it gets into the 90's
or higher, it's really marginal.

Usually the first thing that happens when it's hot outside and I drive
up a shallow grade (after a half hour at freeway speed) is that the
aircon stops cooling. The temperature gauge remains at its normal
point, where it's run within a couple of needle widths since the car
was new. I get off onto (flat) surface streets about that time on the
way home, and in about 5 minutes the aircon usually comes back on.
When I pull in to the garage, if I shut down but turn the ignition
back on (the Lexus fans don't stay on with it off) the fans stay on
high for five or ten minutes, then drop to low for a couple of
minutes.

Today it was near 100, and the aircon actually shut down much earlier,
on a section of the road that you'd have to know to realize it was
climbing a bit. It came back on after a few minutes. Then at the hill
it shut down and for the first time I can remember the temperature
gauge climbed to about halfway between the normal point and the red
line. I took it relatively easy up the hill, but it stayed at that
temperature the rest of the way home. I left the fans running and it
cooled off fairly quickly. I figured I'd lost a lot of water, but in
fact it didn't seem so, although I refilled the expansion bottle after
while.

The water pump was replaced a few years ago, and at least isn't
leaking. The thermostat is just a few months old, genuine Toyota part
fwiw. No water in the oil, and mechanic thinks engine problem is
unlikely since he thinks gasket/block problem would show the problem
even at normal outside temperatures, not just when hot.

The only other symptom I can think of is when I turn the heater on
there's a "waterfall" sound especially if I accelerate up a ramp.

My present prime suspect is the radiator, for no good reason other
than it was cheap.. It's an aftermarket replacement I got several
years ago when the plastic tank on the oem cracked. I'm thinking
perhaps I shouldn't have bought it from the guy who gave me the
cheapest price on the phone. It was okay for a while, of course,
otherwise I would have taken it back and had a word with the
installer.

Thanks for your comments.



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Old 28 Apr 2004, 02:06 am   #2 (permalink)
Bruce Chang
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Default Re: Yet another overheating problem, please


"JT" <NgPoster@missing.org> wrote in message
news:i9gu80h3enpsg7tpg4kk7cgfnsser4c4ft@4ax.com...
> My 1990 Lexus ES250 (aka Camry V6) has had an annoying but not fatal
> cooling problem for a couple of years, without any significant change.
>
> The car runs flawlessly if the outside temperature is no higher than
> say the mid 80's or maybe a bit higher, but when it gets into the 90's
> or higher, it's really marginal.
>
> Usually the first thing that happens when it's hot outside and I drive
> up a shallow grade (after a half hour at freeway speed) is that the
> aircon stops cooling. The temperature gauge remains at its normal
> point, where it's run within a couple of needle widths since the car
> was new. I get off onto (flat) surface streets about that time on the
> way home, and in about 5 minutes the aircon usually comes back on.
> When I pull in to the garage, if I shut down but turn the ignition
> back on (the Lexus fans don't stay on with it off) the fans stay on
> high for five or ten minutes, then drop to low for a couple of
> minutes.
>
> Today it was near 100, and the aircon actually shut down much earlier,
> on a section of the road that you'd have to know to realize it was
> climbing a bit. It came back on after a few minutes. Then at the hill
> it shut down and for the first time I can remember the temperature
> gauge climbed to about halfway between the normal point and the red
> line. I took it relatively easy up the hill, but it stayed at that
> temperature the rest of the way home. I left the fans running and it
> cooled off fairly quickly. I figured I'd lost a lot of water, but in
> fact it didn't seem so, although I refilled the expansion bottle after
> while.
>
> The water pump was replaced a few years ago, and at least isn't
> leaking. The thermostat is just a few months old, genuine Toyota part
> fwiw. No water in the oil, and mechanic thinks engine problem is
> unlikely since he thinks gasket/block problem would show the problem
> even at normal outside temperatures, not just when hot.
>
> The only other symptom I can think of is when I turn the heater on
> there's a "waterfall" sound especially if I accelerate up a ramp.
>
> My present prime suspect is the radiator, for no good reason other
> than it was cheap.. It's an aftermarket replacement I got several
> years ago when the plastic tank on the oem cracked. I'm thinking
> perhaps I shouldn't have bought it from the guy who gave me the
> cheapest price on the phone. It was okay for a while, of course,
> otherwise I would have taken it back and had a word with the
> installer.
>
> Thanks for your comments.
>
>
>


Have you ever opened the radiator cap and looked in the radiator? You may
have a full expansion tank but your radiator might be dry.

I didn't really see anything that said you checked it so I figured I'd
mention the simple things first.


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Old 28 Apr 2004, 05:59 am   #3 (permalink)
m Ransley
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Default Re: Yet another overheating problem, please

How often have you changed your antifreeze, How often has it been
completely flushed.
Do you have an air bleed on the motor.
Do you run a 50-50 or less mix
A new thermostat doesnt mean it hasnt gone bad.
Try a professional flush, a 25% antifreeze mix, New thermostat. Look at
your radiator to see if visible buildup is evident .

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Old 28 Apr 2004, 08:08 am   #4 (permalink)
JimV
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Default Re: Yet another overheating problem, please

JT wrote:

> My 1990 Lexus ES250 (aka Camry V6) has had an annoying but not fatal
> cooling problem for a couple of years, without any significant change.
>
> The car runs flawlessly if the outside temperature is no higher than
> say the mid 80's or maybe a bit higher, but when it gets into the 90's
> or higher, it's really marginal.
>
> Usually the first thing that happens when it's hot outside and I drive
> up a shallow grade (after a half hour at freeway speed) is that the
> aircon stops cooling. The temperature gauge remains at its normal
> point, where it's run within a couple of needle widths since the car
> was new. I get off onto (flat) surface streets about that time on the
> way home, and in about 5 minutes the aircon usually comes back on.
> When I pull in to the garage, if I shut down but turn the ignition
> back on (the Lexus fans don't stay on with it off) the fans stay on
> high for five or ten minutes, then drop to low for a couple of
> minutes.
>
> Today it was near 100, and the aircon actually shut down much earlier,
> on a section of the road that you'd have to know to realize it was
> climbing a bit. It came back on after a few minutes. Then at the hill
> it shut down and for the first time I can remember the temperature
> gauge climbed to about halfway between the normal point and the red
> line. I took it relatively easy up the hill, but it stayed at that
> temperature the rest of the way home. I left the fans running and it
> cooled off fairly quickly. I figured I'd lost a lot of water, but in
> fact it didn't seem so, although I refilled the expansion bottle after
> while.
>
> The water pump was replaced a few years ago, and at least isn't
> leaking. The thermostat is just a few months old, genuine Toyota part
> fwiw. No water in the oil, and mechanic thinks engine problem is
> unlikely since he thinks gasket/block problem would show the problem
> even at normal outside temperatures, not just when hot.
>
> The only other symptom I can think of is when I turn the heater on
> there's a "waterfall" sound especially if I accelerate up a ramp.
>
> My present prime suspect is the radiator, for no good reason other
> than it was cheap.. It's an aftermarket replacement I got several
> years ago when the plastic tank on the oem cracked. I'm thinking
> perhaps I shouldn't have bought it from the guy who gave me the
> cheapest price on the phone. It was okay for a while, of course,
> otherwise I would have taken it back and had a word with the
> installer.
>
> Thanks for your comments.


If the fan kicks on when it should, then I'd replace the radiator. It
was probably marginal to begin with and is now partially clogged.

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Old 28 Apr 2004, 08:33 am   #5 (permalink)
TCS
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Default Re: Yet another overheating problem, please

On Wed, 28 Apr 2004 09:08:51 -0400, JimV <jv9999@yahoo.com> wrote:
>JT wrote:


>> My 1990 Lexus ES250 (aka Camry V6) has had an annoying but not fatal
>> cooling problem for a couple of years, without any significant change.
>>
>> The car runs flawlessly if the outside temperature is no higher than
>> say the mid 80's or maybe a bit higher, but when it gets into the 90's
>> or higher, it's really marginal.
>>
>> Usually the first thing that happens when it's hot outside and I drive
>> up a shallow grade (after a half hour at freeway speed) is that the
>> aircon stops cooling. The temperature gauge remains at its normal
>> point, where it's run within a couple of needle widths since the car
>> was new. I get off onto (flat) surface streets about that time on the
>> way home, and in about 5 minutes the aircon usually comes back on.
>> When I pull in to the garage, if I shut down but turn the ignition
>> back on (the Lexus fans don't stay on with it off) the fans stay on
>> high for five or ten minutes, then drop to low for a couple of
>> minutes.
>>
>> Today it was near 100, and the aircon actually shut down much earlier,
>> on a section of the road that you'd have to know to realize it was
>> climbing a bit. It came back on after a few minutes. Then at the hill
>> it shut down and for the first time I can remember the temperature
>> gauge climbed to about halfway between the normal point and the red
>> line. I took it relatively easy up the hill, but it stayed at that
>> temperature the rest of the way home. I left the fans running and it
>> cooled off fairly quickly. I figured I'd lost a lot of water, but in
>> fact it didn't seem so, although I refilled the expansion bottle after
>> while.
>>
>> The water pump was replaced a few years ago, and at least isn't
>> leaking. The thermostat is just a few months old, genuine Toyota part
>> fwiw. No water in the oil, and mechanic thinks engine problem is
>> unlikely since he thinks gasket/block problem would show the problem
>> even at normal outside temperatures, not just when hot.
>>
>> The only other symptom I can think of is when I turn the heater on
>> there's a "waterfall" sound especially if I accelerate up a ramp.
>>
>> My present prime suspect is the radiator, for no good reason other
>> than it was cheap.. It's an aftermarket replacement I got several
>> years ago when the plastic tank on the oem cracked. I'm thinking
>> perhaps I shouldn't have bought it from the guy who gave me the
>> cheapest price on the phone. It was okay for a while, of course,
>> otherwise I would have taken it back and had a word with the
>> installer.
>>
>> Thanks for your comments.


>If the fan kicks on when it should, then I'd replace the radiator. It
>was probably marginal to begin with and is now partially clogged.


Does the lexus have a bleeder valve for removing air from the heads?
Would explain the waterfall sound.
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Old 28 Apr 2004, 08:51 am   #6 (permalink)
m Ransley
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Default Re: Yet another overheating problem, please

Using a greater than 50-50 antifreeze mixture will reduce cooling-heat
transfer. Test mixture and try reducing it to 25 antifreeze-75 water by
adding distilled water.
Do both cooling fans run, one or both should come on when the AC is
turned on.
Do fans come on when motor is hot.
The pressure cap on the radiator should be replaced it may open to
early..
Water pump belt may be bad or out of adjustment .
Engine timing my be advanced, does the motor knock on acceleration.
The cheap radiator may be bad or to small or defective, or clogged.

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Old 28 Apr 2004, 09:22 am   #7 (permalink)
JT
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Default Re: Yet another overheating problem, please

TCS <The-Central-Scrutinizer@p.o.b.o.x.com> wrote:


>
>>If the fan kicks on when it should, then I'd replace the radiator. It
>>was probably marginal to begin with and is now partially clogged.

>
>Does the lexus have a bleeder valve for removing air from the heads?
>Would explain the waterfall sound.


Thanks. There's a bolt up on the engine that's supposed to be at the
high point that you're supposed to back out to release air, but I
haven't gotten anything out but water. The service manual doesn't
mention anything about otherwise-trapped air in the cooling section. I
should look to see if the heater itself gets discussed in a different
place.

Any recommendation for a top-quality radiator? A lot of them just seem
to compete on price, and that isn't necessarily a mistake I want to
repeat. The only variation I see is that one outfit sells two
different kinds: one is like the oem and has the plastic expansion
tank (not my favorite, but if it lasts a few years without cracking
and meanwhile does the job, so be it). The interesting thing is that
they advertise "copper and brass core" or something like that. Their
other choice is merely "all metal". Both cost about the same, fwiw.
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Old 28 Apr 2004, 09:23 am   #8 (permalink)
JT
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Default Re: Yet another overheating problem, please

"Bruce Chang" <bechang@swspambegonebell.com> wrote:

>Have you ever opened the radiator cap and looked in the radiator? You may
>have a full expansion tank but your radiator might be dry.
>
>I didn't really see anything that said you checked it so I figured I'd
>mention the simple things first.
>

Good enough question, but yup, the radiator cap is doing its to and
fro thing properly and the radiator is full of liquid.
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Old 28 Apr 2004, 09:28 am   #9 (permalink)
JT
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Default Re: Yet another overheating problem, please

ransley@webtv.net (m Ransley) wrote:

>How often have you changed your antifreeze, How often has it been
>completely flushed.
>Do you have an air bleed on the motor.
>Do you run a 50-50 or less mix
>A new thermostat doesnt mean it hasnt gone bad.
>Try a professional flush, a 25% antifreeze mix, New thermostat. Look at
>your radiator to see if visible buildup is evident .


Thanks, ransley. Changed antifreeze with new thermostat, of necessity,
maybe six or nine months ago. No agressive system flush then,
though.No particular crap in the water. I generally run about 50-50
(Lexus actually suggests 70% antifreeze) but don't make a science
project out of it. Temp guage zips up to operating temp in the first
five minutes of driving and stays there. You don't quite have to pull
the engine to replace it, but it's not like it used to be, so I don't
think I'm quite ready for a new one quite yet. No obvious buildup,
wish it were that easy.
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Old 28 Apr 2004, 09:39 am   #10 (permalink)
JT
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Default Re: Yet another overheating problem, please

ransley@webtv.net (m Ransley) wrote:

>Using a greater than 50-50 antifreeze mixture will reduce cooling-heat
>transfer. Test mixture and try reducing it to 25 antifreeze-75 water by
>adding distilled water.
> Do both cooling fans run, one or both should come on when the AC is
>turned on.
> Do fans come on when motor is hot.
> The pressure cap on the radiator should be replaced it may open to
>early..
> Water pump belt may be bad or out of adjustment .
> Engine timing my be advanced, does the motor knock on acceleration.
>The cheap radiator may be bad or to small or defective, or clogged.


Thanks. I thought ethylene glycol was better at heat capacity and
transfer than water.

Both fans run fine afaik, although I don't think that merely turning
on the AC turns on a fan. They appear to behave properly when the
water is hot. Radiator cap is relatively new and didn't do anything
too different when it was brand new.

Remember, this problem has been going on for several years - the
machine works fine if it's 80 degrees or less outside, which even in
LA is most of the time, and even when it's hot I have to run at speed
for 15 minutes or so and then climb that little hill to even get the
a/c to go off. Yesterday it was a bit over 100 and I had to pick the
kid up from school, longer than my usual afternoon drive. The temp
gauge going above the normal point got my attention as it hadn't been
doing that - I figured I'd lost a lot of water and was surprised that
wasn't the case.

I'm certainly inclined to replace the radiator - relatively cheap
thrills - and appreciate all the feedback. Everyone please tell me who
makes great radiators and who to avoid.
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