Overheating Subaru Legacy AWD Wagon...

"hachiroku" > wrote in message
news
> On Mon, 26 Nov 2007 23:43:38 -0600, Ray O wrote:
>
>>>
>>> "Hydrocarbons in coolant overflow tank, this is tested by a mechanic
>>> with
>>> specialized equipment and is not evident visually."
>>>
>>>
>>> Having this looked at Wednesday...
>>>
>>> Is there any way I can check this myself?
>>>
>>
>> If you have an electronic gas sniffer, you can stick the probe into the
>> radiator neck or overflow tank.
>> --
>
>
> Way ahead of you, Ray! Brought it for MA state inspection (remember
> those?) He put the gas sniffer for the tailpipe in the filler neck and
> there were PLENTY of hydrocarbons coming out through the radiator!!!
>
Yup, I remember MA state inspections. I was driving a hard plated pool
Cressida (not my regular company car)and got pulled over in downtown Boston
for not having an inspection sticker on the car. Since the car was
registered to the company, the officer was kind enough to issue the ticket
to the company instead of me.

As far as the Legacy, my advice is to dump it unless Subaru has made some
kind of improvement in the design to prevent future reoccurrences.
--

Ray O
(correct punctuation to reply)

On Nov 25, 10:10 pm, Hachiroku $B%O%A%m%/(B > wrote:
> 1997SubaruAWD wagon, "L" model, basic car.
>
> On the first drive yesterday, I got about 8 miles and it began
> overheating, after running static for about 40 mins with no problems. ....

I have been struggling since August with very similar problems with a
'98 Legacy Outback, 2.5L engine. The problem appeared after I
replaced a broken heater hose. To make a very long story short, the
cooling system now seems incapable of handling the transition from
high load, high coolant flow conditions (e.g. highway driving) to
light load, low flow (e.g. suddenly slowing down in traffic). The
temperature gauge will spike from the normal 9 o'clock position to
offscale hot in about 30 seconds. If you see this happening and
immediately place the car in neutral and rev the engine to about
4,000RPM, the system will usually recover, with the temperature gauge
dropping back to below 9 o'clock within 30 seconds. If you don't
catch it fast enough, the coolant will boil over. The car has no
problem cooling during extended driving in stop and go traffic on hot
summer days, only the transitions bother it. It appears the
thermostat can't open fast enough to deal with the changing load- but
no thermostat is going to respond on a timescale of seconds. The
cooling system was pressure tested by a local garage, who found no
problem. Drilling a few 1/8" bypass holes in the thermostat flange to
allow some coolant flow even when the thermostat is closed seems to
have provided a solution to the problem, but with temperatures often
going to -20C here the engine doesn't warm up properly. (It's worth
noting that in a post a few years back the owner of a used Legacy of
this vintage discovered the thermostat had been removed, and found
overheating problems when a new thermostat was installed). I have
filled the cooling system as slowly and carefully as I can, including
extended running at idle with the radiator cap off to "burp" the
system. The burping seems to go on for a long, long time, suggesting
it is very difficult to get air out of the system. If anyone has a
solution to this strange problem, I'd really appreciate hearing it. In
the meantime I'm living with the bypassed thermostat.

Garry

wrote:
> I have been struggling since August with very similar problems with a
> '98 Legacy Outback, 2.5L engine. The problem appeared after I
> replaced a broken heater hose. To make a very long story short, the
> cooling system now seems incapable of handling the transition from
> high load, high coolant flow conditions (e.g. highway driving) to
> light load, low flow (e.g. suddenly slowing down in traffic). The
> temperature gauge will spike from the normal 9 o'clock position to
> offscale hot in about 30 seconds. If you see this happening and
> immediately place the car in neutral and rev the engine to about
> 4,000RPM, the system will usually recover, with the temperature gauge
> dropping back to below 9 o'clock within 30 seconds. If you don't
> catch it fast enough, the coolant will boil over. The car has no
> problem cooling during extended driving in stop and go traffic on hot
> summer days, only the transitions bother it. It appears the
> thermostat can't open fast enough to deal with the changing load- but
> no thermostat is going to respond on a timescale of seconds.

This sounds very much like what happened when I changed the thermostat in
my '94 Acclaim 3.0L. I found that the old thermostat had a considerably
bigger orifice; I believe the smaller orifice on the new 'stat is
restricting flow somewhat.

--
Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
Indonesia, for the United Nations meeting on climate change will cause
as much pollution as 20,000 cars in a year.

wrote:
> On Nov 25, 10:10 pm, Hachiroku $B%O%A%m%/(B > wrote:
>
>>1997SubaruAWD wagon, "L" model, basic car.
>>
>>On the first drive yesterday, I got about 8 miles and it began
>>overheating, after running static for about 40 mins with no problems. ....
>
>
> I have been struggling since August with very similar problems with a
> '98 Legacy Outback, 2.5L engine. The problem appeared after I
> replaced a broken heater hose. To make a very long story short, the
> cooling system now seems incapable of handling the transition from
> high load, high coolant flow conditions (e.g. highway driving) to
> light load, low flow (e.g. suddenly slowing down in traffic). The
> temperature gauge will spike from the normal 9 o'clock position to
> offscale hot in about 30 seconds. If you see this happening and
> immediately place the car in neutral and rev the engine to about
> 4,000RPM, the system will usually recover, with the temperature gauge
> dropping back to below 9 o'clock within 30 seconds. If you don't
> catch it fast enough, the coolant will boil over. The car has no
> problem cooling during extended driving in stop and go traffic on hot
> summer days, only the transitions bother it. It appears the
> thermostat can't open fast enough to deal with the changing load- but
> no thermostat is going to respond on a timescale of seconds. The
> cooling system was pressure tested by a local garage, who found no
> problem. Drilling a few 1/8" bypass holes in the thermostat flange to
> allow some coolant flow even when the thermostat is closed seems to
> have provided a solution to the problem, but with temperatures often
> going to -20C here the engine doesn't warm up properly. (It's worth
> noting that in a post a few years back the owner of a used Legacy of
> this vintage discovered the thermostat had been removed, and found
> overheating problems when a new thermostat was installed). I have
> filled the cooling system as slowly and carefully as I can, including
> extended running at idle with the radiator cap off to "burp" the
> system. The burping seems to go on for a long, long time, suggesting
> it is very difficult to get air out of the system. If anyone has a
> solution to this strange problem, I'd really appreciate hearing it. In
> the meantime I'm living with the bypassed thermostat.
>
> Garry


It certainly sounds like you're doing a lot of the right things.

Um, are you certain the 'burping' is done with the heat set on 'max' and
have you changed the radiator cap?

Can't really think of anything else - maybe someone will have some more
suggestions.

Carl


--
to reply, change ( .not) to ( .net)

I had a very similar problem once on my 98 outback. It ended up being
the thermostat - I changed it once because the car wouldn't heat up
and then it began overheating. It turned out to be a faulty
thermostat so i got an OEM one from the subaru garage and it solved my
problems. Although, you've already replaced your thermostat I'd
recommend trying a second one - I was about ready to replace my water
pump and had already had my radiator checked for blockages before I
changed the thermostat a second time. According to the radiator shop
where I had my radiator checked, faulty thermostats are common - the
guy told me a story of having to buy four once before getting one that
worked.

I tried a new radiator cap- no improvement. I've been "burping"
parked on a steep incline with the rad higher than the engine and the
heat on max, although I think coolant always circulates in the heater
core no matter what the heater setting.

The new thermostat (second source) and the Subaru original showed
identical behaviour when heated in water, both opening nicely at the
temperature stamped on the thermostat. I suspect both are working as
designed. The Subaru thermostat has a slightly larger aperture.

The car is not consuming coolant so I think the head gasket is OK.

Even after repeated "burping" sessions there are still bubbles
appearing, so I suspect it is very difficult to bleed the air from the
system.

Thanks,

Garry

> Um, are you certain the 'burping' is done with the heat set on 'max' and
> have you changed the radiator cap?
>
> Can't really think of anything else - maybe someone will have some more
> suggestions.
>
> Carl
>

On Nov 27 2007, 4:13*am, hachiroku > wrote:
> On Sun, 25Nov200722:23:45 -0600, Carl 1 Lucky Texan wrote:
>
> >> If you can get an exhaust sniffer, check for exhaust gas at the radiator
> >> neck. *When you filled the coolant, you did have the heater set to full hot,
> >> right?
>
> > Good post.
> > I think he did more things correctly than most. The ONLY other thing to
> > consider would be filling/burping the system with the front of the car
> > elevated
>
> <SIGH> It was up on ramps...BHG I'm afraid...

Look under Subaru thermostat operation I might be able to help

On Dec 19 2007, 8:48 am, Carl 1 Lucky Texan >
wrote:
> wrote:
> > On Nov 25, 10:10 pm, Hachiroku $B%O%A%m%/(B > wrote:
>
> >>1997SubaruAWD wagon, "L" model, basic car.
>
> >>On the first drive yesterday, I got about 8 miles and it began
> >>overheating, after running static for about 40 mins with no problems. ....
>
> > I have been struggling since August with very similar problems with a
> > '98 Legacy Outback, 2.5L engine. The problem appeared after I
> > replaced a broken heater hose. To make a very long story short, the
> > cooling system now seems incapable of handling the transition from
> > high load, high coolant flow conditions (e.g. highway driving) to
> > light load, low flow (e.g. suddenly slowing down in traffic). The
> > temperature gauge will spike from the normal 9 o'clock position to
> > offscale hot in about 30 seconds. If you see this happening and
> > immediately place the car in neutral and rev the engine to about
> > 4,000RPM, the system will usually recover, with the temperature gauge
> > dropping back to below 9 o'clock within 30 seconds. If you don't
> > catch it fast enough, the coolant will boil over. The car has no
> > problem cooling during extended driving in stop and go traffic on hot
> > summer days, only the transitions bother it. It appears the
> > thermostat can't open fast enough to deal with the changing load- but
> > no thermostat is going to respond on a timescale of seconds. The
> > cooling system was pressure tested by a local garage, who found no
> > problem. Drilling a few 1/8" bypass holes in the thermostat flange to
> > allow some coolant flow even when the thermostat is closed seems to
> > have provided a solution to the problem, but with temperatures often
> > going to -20C here the engine doesn't warm up properly. (It's worth
> > noting that in a post a few years back the owner of a used Legacy of
> > this vintage discovered the thermostat had been removed, and found
> > overheating problems when a new thermostat was installed). I have
> > filled the cooling system as slowly and carefully as I can, including
> > extended running at idle with the radiator cap off to "burp" the
> > system. The burping seems to go on for a long, long time, suggesting
> > it is very difficult to get air out of the system. If anyone has a
> > solution to this strange problem, I'd really appreciate hearing it. In
> > the meantime I'm living with the bypassed thermostat.
>
> > Garry
>
> It certainly sounds like you're doing a lot of the right things.
>
> Um, are you certain the 'burping' is done with the heat set on 'max' and
> have you changed the radiator cap?
>
> Can't really think of anything else - maybe someone will have some more
> suggestions.
>
> Carl
>
> --
> to reply, change ( .net) to ( .net)

There must be something wrong with the heater hose Read subaru
thermostat operation Michael

On Sunday, November 25, 2007 7:10:54 PM UTC-8, Hachiroku ãƒ�ãƒ�ãƒ*ク wrote:
> 1997 Subaru AWD wagon, "L" model, basic car. Replaced coolant and
> thermostat and ran car static for an hour at a time about 3 times. Would
> initially overheat (when I replaced the coolant), cold air coming from the
> heater, then heat started coming from the vents and the guage went down.
> As I was getting it ready to pass inspection I would run it for 40-60
> minutes, temp guage rock-steady at half way, heat from the vents, etc.
>
> On the first drive yesterday, I got about 8 miles and it began
> overheating, after running static for about 40 mins with no problems. I
> shut it down and let it cool and drove it home. Sometimes raising the revs
> causes the temp to decrease, and sometimes to increase. Sometimes coasting
> cools the car off, and sometimes raises the temp. Putting it in neutral
> has no effect; it keeps getting warmer.
>
> When I opened the bleeder screw, pure steam was coming out of it. From the
> front of the car, the right side (driver's side) appears to have coolant
> in the lower radiator hose where the thermostat is, and the upper hose
> looks empty.
>
> I don't know what size the engine is. It came from the factory with a 2.2,
> but it has been replaced, with another 2.2? I was told the trans had been
> replaced with a FWD trans, but the sticker on the trans matches the VIN
> plate, which indicates AWD. Trans works great, car runs well, except for
> the overheating. I replaced the t-stat, and the one that was in there
> looked new also. I'll have it flushed sometime this week.
>
> Anyone seen this before, or have any idea what's going on here? It looks
> like a blockage somewhere.