ON Topic: 88 Supra overheating...

[Hachiroku $B%O%A%m%/(B]

I know there are techs in all three groups, hence the cross posting....

The other day, the day it got clobbered by the storm, it was 96 degrees in
Keene NH. That's ~35 miles from home. Since it was nice I decided to take
the roof off the Supra and use it for my daily rounds.

Everything was fine until about mile 27, and then I noticed the temp
climbing. By the time I got to my first stop it was almost to the red.

It behaved the rest of the time in Keene, and then, about 27 miles later
it was heating up again.

I opened the radiator and it was down about a quart, but the bottle was on
"low". I filled the radiator and let it sit for a couple rainy days.

Today was bright and sunny and about 86 degrees, so, since the roof
doesn't *quite* fit as well after making like a kite it sits in the trunk,
and again the ~35 mile trip to Keene. 27 miles up the road...almost in the
red again. When I got to where I pick up my parts I let it cool and then
opened the hood, and in front of the radiator the shroud attached to the
bottom of the car was wet, and the overflow bottle was FULL. Spring a
leak? I patched one split in the plastic top a couple years ago, and it
had sprung again. When I filled it I did not add any to the bottle.

It ran OK for the few stops I had, then back home...27 miles...

When I got home I left the heat on and would start it, ramp the non
eletric fan up and shut it down. After about 1/2 an hour letting it sit, I
went out and gingerly removed the radiator cap. The cap was COOL! Again...
down about a quart in the readiator, but this time the bottle was full.

I am guessing the radiator is plugged up. It is the original 22 year old
radiator, so I ordered a new one. From Toyota? HAH! Even though they last
+20 years, they are also FOUR HUNDRED AND EIGHTY SEVEN DOLLARS!!!

SPI, $130. It may only last seven years, but then, how much longer will
the car last? (Although it is in pretty good shape...)

BTW, I had the SAME THING happen to my '89 Subaru GL coupe, and after
replacing the radiator I don't even need the fan, the thing runs so cool.

 

[Ray O]

I know there are techs in all three groups, hence the cross posting....

The other day, the day it got clobbered by the storm, it was 96 degrees in
Keene NH. That's ~35 miles from home. Since it was nice I decided to take
the roof off the Supra and use it for my daily rounds.

Everything was fine until about mile 27, and then I noticed the temp
climbing. By the time I got to my first stop it was almost to the red.

It behaved the rest of the time in Keene, and then, about 27 miles later
it was heating up again.

I opened the radiator and it was down about a quart, but the bottle was on
"low". I filled the radiator and let it sit for a couple rainy days.

Today was bright and sunny and about 86 degrees, so, since the roof
doesn't *quite* fit as well after making like a kite it sits in the trunk,
and again the ~35 mile trip to Keene. 27 miles up the road...almost in the
red again. When I got to where I pick up my parts I let it cool and then
opened the hood, and in front of the radiator the shroud attached to the
bottom of the car was wet, and the overflow bottle was FULL. Spring a
leak? I patched one split in the plastic top a couple years ago, and it
had sprung again. When I filled it I did not add any to the bottle.

It ran OK for the few stops I had, then back home...27 miles...

When I got home I left the heat on and would start it, ramp the non
eletric fan up and shut it down. After about 1/2 an hour letting it sit, I
went out and gingerly removed the radiator cap. The cap was COOL! Again...
down about a quart in the readiator, but this time the bottle was full.

I am guessing the radiator is plugged up. It is the original 22 year old
radiator, so I ordered a new one. From Toyota? HAH! Even though they last
+20 years, they are also FOUR HUNDRED AND EIGHTY SEVEN DOLLARS!!!

SPI, $130. It may only last seven years, but then, how much longer will
the car last? (Although it is in pretty good shape...)

BTW, I had the SAME THING happen to my '89 Subaru GL coupe, and after
replacing the radiator I don't even need the fan, the thing runs so cool.

Replace the cap while you're at it.

 

[Hachiroku $B%O%A%m%/(B]

Replace the cap while you're at it.

I think it comes with one.

I was thinking about that, but the cap is openeing up and letting the
coolant flow into the bottle.

The coolant I saw in the shroud was the stuff that was being purged out of
the bottle...

I think I might actually get a real Toyota cap, if it fits. They're only
$11...

 

[Tegger]

On Wed, 02 Jun 2010 23:04:28 -0500, Ray O wrote:


I think it comes with one.

I was thinking about that, but the cap is openeing up and letting the
coolant flow into the bottle.

Yeah, but is it opening at a too-low pressure? If it is, the coolant will
boil and spew all over the place. Bad juju, bwana...

The coolant I saw in the shroud was the stuff that was being purged
out of the bottle...

Either a bad rad-cap, or you've got a blown head gasket. How's the stuff in
the bottle smell? Rubbery? Or like paint-thinner?

I think I might actually get a real Toyota cap, if it fits. They're
only $11...

You use /aftermarket/ rad caps? Eww, gross. OEM-only, for me.

 

[Hachiroku $B%O%A%m%/(B]

Either a bad rad-cap, or you've got a blown head gasket.

DO NOT say this!!! We're talking a Supra here! Not that a 1986-1991 Supra
would *EVER* blow a head gasket!!!

This is the one thing I'm praying it's not...

AFAIK, the head gasket has already been replaced and the bolts torqued to
the new spec. I'm praying REALLY hard... (Although it doesn't look like
that hard a job. I was already 2/3 of the way there when I replaced the
spark plugs...)

 

[Hachiroku $B%O%A%m%/(B]

Yeah, but is it opening at a too-low pressure? If it is, the coolant will
boil and spew all over the place. Bad juju, bwana...





Either a bad rad-cap, or you've got a blown head gasket. How's the stuff
in the bottle smell? Rubbery? Or like paint-thinner?





You use /aftermarket/ rad caps? Eww, gross. OEM-only, for me.

AARRGGHH...

How do I know if I’ve blown a gasket?

The most usual means of detecting a BHG is by noticing your temperature
gauge skyrocketing. A BHG does not directly cause the engine to run hotter
- the break in the gasket allows combustion gasses to leak into the
cooling system, forcing radiator water out into the overflow bottle.

 

[jim beam]

AARRGGHH...

How do I know if I’ve blown a gasket?

The most usual means of detecting a BHG is by noticing your temperature
gauge skyrocketing. A BHG does not directly cause the engine to run hotter
- the break in the gasket allows combustion gasses to leak into the
cooling system, forcing radiator water out into the overflow bottle.

and when it does that, the bubbles in the system mean less liquid volume
in the cooling passages, thus you get overheating...

get one of those chemical leak test kits. the pH of the coolant changes
if the gasket is leaking - provided you haven't masked it by changing
the coolant too recently.

 

[Hachiroku $B%O%A%m%/(B]

and when it does that, the bubbles in the system mean less liquid volume
in the cooling passages, thus you get overheating...

get one of those chemical leak test kits. the pH of the coolant changes
if the gasket is leaking - provided you haven't masked it by changing the
coolant too recently.

I haven't changed it, but I added some the day before.

We found the BHG in my Soob by removing the rad cap and sticking the
hydrocarbon probe at the Emission Inspection station in the radiator. I
don't know if they have them any more since it's all OBD-II now...

 

[Ray O]

I think it comes with one.

I was thinking about that, but the cap is openeing up and letting the
coolant flow into the bottle.

The coolant I saw in the shroud was the stuff that was being purged out of
the bottle...

I think I might actually get a real Toyota cap, if it fits. They're only
$11...

A bad cap will open too soon so the cooling system doesn't maintain
pressure, and if the cooling system doesn't maintain pressure, the boiling
temp goes down, more coolant gets pushed out, air gets in, and temps rise.

A blown head gasket can allow combustion gases into the coolant, which
pushes coolant out, and temps rise.

Look for oil in the coolant, either in the radiator or a milkshake
appearance in the oil. Either symptom can indicate a BHG. If the coolant
and oil are pristine, then you have a leak somewhere in the cooling system -
radiator, hoses, cap, or heater core.

While you're poking around make sure coolant isn't weeping or leaking from
the timing cover, a sign of a leaking water pump.

 

[Ray O]

I haven't changed it, but I added some the day before.

We found the BHG in my Soob by removing the rad cap and sticking the
hydrocarbon probe at the Emission Inspection station in the radiator. I
don't know if they have them any more since it's all OBD-II now...

A gas leak detector will work.

 

[jim beam]

A bad cap will open too soon so the cooling system doesn't maintain
pressure, and if the cooling system doesn't maintain pressure, the boiling
temp goes down, more coolant gets pushed out, air gets in, and temps rise.

A blown head gasket can allow combustion gases into the coolant, which
pushes coolant out, and temps rise.

Look for oil in the coolant, either in the radiator or a milkshake
appearance in the oil. Either symptom can indicate a BHG. If the coolant
and oil are pristine, then you have a leak somewhere in the cooling system -
radiator, hoses, cap, or heater core.

with open deck designs, like honda d-series for instance, you only
occasionally get oil/water mixing. with open deck, leakage vents
exhaust gas straight into the coolant. the only symptoms are bubbling,
even when cold as it gets bad, and the coolant pH test. and latterly of
course, blown hoses and catastrophic coolant loss.

 

[Tegger]

=?iso-2022-jp?q?Hachiroku_=1B$B%O%A%m%=2F=1B=28B?= <(e-mail address removed)>
wrote in

How do I know if I've blown a gasket?

How's the stuff in the bottle/rad smell? Rubbery? Or like paint-thinner?

 

[Tegger]

A gas leak detector will work.

Like this one?
<http://www.grahamtool.com/combustionleakdetector.aspx>

 

[Hachiroku $B%O%A%m%/(B]

A bad cap will open too soon so the cooling system doesn't maintain
pressure, and if the cooling system doesn't maintain pressure, the boiling
temp goes down, more coolant gets pushed out, air gets in, and temps rise.

A blown head gasket can allow combustion gases into the coolant, which
pushes coolant out, and temps rise.

Look for oil in the coolant, either in the radiator or a milkshake
appearance in the oil. Either symptom can indicate a BHG. If the coolant
and oil are pristine, then you have a leak somewhere in the cooling system
- radiator, hoses, cap, or heater core.

While you're poking around make sure coolant isn't weeping or leaking from
the timing cover, a sign of a leaking water pump.

The coolant in the bottle looked OK. The coolant in the
radiator...couldn't be seen. It must have blown a lot of it out. Last time
it took a quart.

I have a new SPI radiator (I know, I know, but it was $123 compared to
$487!) so I'll remove the rad, drain and flush the cooling system, and
then replace and refill, and cross my fingers...

And, of course, after being nice yesterday and today, it's going to rain
all weekend, and then be really nice for the next four days after...

BTW, I haven't checked the oil yet. I'll do that tomorrow.

 

[Hachiroku $B%O%A%m%/(B]

Like this one?
<http://www.grahamtool.com/combustionleakdetector.aspx>

Hey! I have one of those! Oh, wait...um, never mind...

 

[clare]

DO NOT say this!!! We're talking a Supra here! Not that a 1986-1991 Supra
would *EVER* blow a head gasket!!!

This is the one thing I'm praying it's not...

If you overheated it , whatever the original cause, you are LIKELY now
looking at another head gasket - and be VERY sure you have the head
checked for warpage when it is off. They are a fantastic engine, on
the whole - but not terribly forgiving of massive overheating.

 

[clare]

get one of those chemical leak test kits. the pH of the coolant changes
if the gasket is leaking - provided you haven't masked it by changing
the coolant too recently.

It's not the PH it is checking - so having changed the coolant 2
weeks ago will have NO effect on the test.

 

[clare]

Look for oil in the coolant, either in the radiator or a milkshake
appearance in the oil. Either symptom can indicate a BHG. If the coolant
and oil are pristine, then you have a leak somewhere in the cooling system -
radiator, hoses, cap, or heater core.

While you're poking around make sure coolant isn't weeping or leaking from
the timing cover, a sign of a leaking water pump.

On the M series engine it is not uncommon for a blown head gasket to
NOT show up as either oil in the coolant or coolant in the oil. The
exhaust sniffer at the rad cap is a pretty good diagnostic - but make
sure NO antifreeze gets into the sniffer - the dedicated test kits
that check for combustion byproducts works quite well - but just
putting the rad pressure tester on a warmed up engine and loading the
engine will tell you FOR SURE. If the needle climbs quicly on an
engine running at normal operating temperature, you have a combustion
pressure leak - guaranteed.

 

[Hachiroku $B%O%A%m%/(B]

If you overheated it , whatever the original cause, you are LIKELY now
looking at another head gasket - and be VERY sure you have the head
checked for warpage when it is off. They are a fantastic engine, on the
whole - but not terribly forgiving of massive overheating.

The sound you just heard was my bubble bursting...

I have a new radiator. If the rain holds off this weekend I'll put it in
(it was needed anyway...) and then take it for a spin. It takes over 25
miles for the engine to start to creep up in temp.

Yeah, I think a new HG is in order...I'm hoping I can get through this
summer OK and do it over the winter.

NOT something I was looking forward to doing...I believe it was replaced
once, a year before I bought it in '04.

 

[Tegger]

=?iso-2022-jp?q?Hachiroku_=1B$B%O%A%m%=2F=1B=28B?= <(e-mail address removed)>
wrote in

Yeah, I think a new HG is in order...I'm hoping I can get through this
summer OK

Not a great idea. Leave it too long and you get corrosion and gas-cutting
on the block surface,both of which will most likely render your engine
uneconomic to repair. Unfortunately, you need to either park your ride or
get this fixed, both ASAP.

So, uh, have you taken a whiff of the expansion bottle yet? It only takes
seconds to do that, and the result could change the entire tendency of this
thread...