98 Outback overheating problem

[Glenn Pure]

Another post on an overheating Outback (1998, 2.5 litre).

This is the first time I've ever had a problem...

1. Turned into my street tonight and notice temperature guage had
climbed to its hotest limit (wasn't like that a minute or two ago).

2. Pulled into drive a few hundred metres away. There was coolant
dripping from the tray under the engine. On inspection, it turned out
the overflow reservoir had filled itself up and overflowed.

3. Left car ignition on for a few minutes to let the thermatic fan
cool things down.

4. Checked reservoir again. It was empty. Carefully touched radiator.
It was cool to touch. Carefully removed radiator cap. Couldn't see any
coolant in there (at least it was very low).

There aren't any obvious leaky pipes or joints. What's happening
here??? Why did my reservoir overflow one minute then such dry the
next when there apparently wasn't much coolant in the radiator in the
first place. Reservoir level was normal when I checked it a week or so
back.

Cheers
Glenn
Glenn Pure
Canberra, Australia
Web page: http://www.evans-pure.net

 

[Mickey]

Another post on an overheating Outback (1998, 2.5 litre).

This is the first time I've ever had a problem...

1. Turned into my street tonight and notice temperature guage had
climbed to its hotest limit (wasn't like that a minute or two ago).

2. Pulled into drive a few hundred metres away. There was coolant
dripping from the tray under the engine. On inspection, it turned out
the overflow reservoir had filled itself up and overflowed.

3. Left car ignition on for a few minutes to let the thermatic fan
cool things down.

4. Checked reservoir again. It was empty. Carefully touched radiator.
It was cool to touch. Carefully removed radiator cap. Couldn't see any
coolant in there (at least it was very low).

There aren't any obvious leaky pipes or joints. What's happening
here??? Why did my reservoir overflow one minute then such dry the
next when there apparently wasn't much coolant in the radiator in the
first place. Reservoir level was normal when I checked it a week or so
back.

Cheers
Glenn
Glenn Pure
Canberra, Australia
Web page: http://www.evans-pure.net

Early 2.5 engines DOHC that had HG problems typ have internal leaks,
between combustion chamber and coolant. If this is the case, while
the engine is running hot combustion gases are gettting into the
cooling system, overheating the coolant and pushing coolant out the
overflow. The fix is new head gaskets.

If the engine is going to be pulled for the repair, in addition to new
timing belt possibly a water pump I would recommend all seals be
replaced as most will be close at hand and would be much more
difficult to change later.

Mickey

 

[johninKY]

As for where the coolant went, it's a pressure differential thing. The
pressure inside the radiator increases with an increase in coolant
temperature, and will also increase if a head gasket is leaking. Whenever
the radiator internal pressure exceeds the radiator cap pressure setting,
the cap opens and coolant flows to the overflow can. When you shut down
the engine, the radiator and coolant inside the radfiator cooled and as a
result a partial vacuum was created inside the radiator. The cap then
opened but this time the ambient atmospheric pressure forced the coolant
in the overflow cannister to flow back into the radiator.

 

[Glenn Pure]

Thanks for the explanations. I'm aware of how the overflow reservoir
works and was hoping it may not be a head gasket. Will get it checked
into and see if a 'quick and dirty' can't be done first with a leak
sealant compound. Will be a lot cheaper than doing the gaskets.

Cheers
Glenn

As for where the coolant went, it's a pressure differential thing. The
pressure inside the radiator increases with an increase in coolant
temperature, and will also increase if a head gasket is leaking. Whenever
the radiator internal pressure exceeds the radiator cap pressure setting,
the cap opens and coolant flows to the overflow can. When you shut down
the engine, the radiator and coolant inside the radfiator cooled and as a
result a partial vacuum was created inside the radiator. The cap then
opened but this time the ambient atmospheric pressure forced the coolant
in the overflow cannister to flow back into the radiator.

Glenn Pure
Canberra, Australia
Web page: http://www.evans-pure.net

 

[Edward Hayes]

The "cooling system conditioner" is for HG weeping and will not cure a
blown HG. Sorry.

 

[Glenn Pure]

Thanks. When I thought about it afterwards, since positive pressure is
coming from cylinder, then it is clear that sealant on the coolant
side will be blown out of the leak point(s), not into them. My
mistake.

Getting car checked on Wednesday and bracing for bad news.

G

The "cooling system conditioner" is for HG weeping and will not cure a
blown HG. Sorry.

Glenn Pure
Canberra, Australia
Web page: http://www.evans-pure.net

 

[Danny Russell]

Early 2.5 engines DOHC that had HG problems typ have internal leaks,
between combustion chamber and coolant.

The phase II SOHC still experiences the internal leak problem PLUS the external leak on top of it.
It's a total crock. -Danny

 

[rajp53]

Please let us know what happens.

 

[Glenn Pure]

Problem diagnosed today by local Subaru service guys.

Blown head gasket. Apparently it went on them big time after they took
it for a drive around the block.

Bummer.

Glenn

Please let us know what happens.

Glenn Pure
Canberra, Australia
Web page: http://www.evans-pure.net

 

[hippo]

Not nice. Hope you're back on the road soon. Mind you, it'll be a few weeks
befre you need much of a cooling system around Canberra! Cheers

 

[Glenn Pure]

Well, I got my Outback from repairer today. They replaced the head
gaskets and various other seals (camshaft seals etc). Also had
radiator checked and flushed.

Overhaul was done on heads due to fact they reckoned the valve stem
seals were leaking. (I had noticed a little oil consumption but had
not told them about this.) All told, cost me just under A$2,000 after
originally being quote $1,500. The only thing I was a bit annoyed
about was that they replaced the spark plugs which are pricey. Car has
done 133,000 km and plugs were replaced at 100,000 (not due again
until 200,000). Not sure why they did this but I can't see any reason.
Any opinions out there?

Cheers
Glenn

Another post on an overheating Outback (1998, 2.5 litre).

This is the first time I've ever had a problem...

1. Turned into my street tonight and notice temperature guage had
climbed to its hotest limit (wasn't like that a minute or two ago).

2. Pulled into drive a few hundred metres away. There was coolant
dripping from the tray under the engine. On inspection, it turned out
the overflow reservoir had filled itself up and overflowed.

3. Left car ignition on for a few minutes to let the thermatic fan
cool things down.

4. Checked reservoir again. It was empty. Carefully touched radiator.
It was cool to touch. Carefully removed radiator cap. Couldn't see any
coolant in there (at least it was very low).

There aren't any obvious leaky pipes or joints. What's happening
here??? Why did my reservoir overflow one minute then such dry the
next when there apparently wasn't much coolant in the radiator in the
first place. Reservoir level was normal when I checked it a week or so
back.

Cheers
Glenn
Glenn Pure
Canberra, Australia
Web page: http://www.evans-pure.net

Glenn Pure
Canberra, Australia
Web page: http://www.evans-pure.net

 

[GrumpyOldGeek]

Well, I got my Outback from repairer today. They replaced the head
gaskets and various other seals (camshaft seals etc). Also had
radiator checked and flushed.

Overhaul was done on heads due to fact they reckoned the valve stem
seals were leaking. (I had noticed a little oil consumption but had
not told them about this.) All told, cost me just under A$2,000 after
originally being quote $1,500. The only thing I was a bit annoyed
about was that they replaced the spark plugs which are pricey. Car has
done 133,000 km and plugs were replaced at 100,000 (not due again
until 200,000). Not sure why they did this but I can't see any reason.
Any opinions out there?

It's hard for me to know what the customs
are in AU regarding repairs. In California,
the shop is required to give you the defective
parts upon demand. If the plugs looked good,
I'd not want to pay for new ones and if they
were bad, I'd be concerned that they didn't
last long. Perhaps you could get them to
charge you their cost for the plugs. Seems
like that would be fair.

 

[Glenn Pure]

Standard practice here is to return replaced parts too, at least in
theory. Doesn't happen very often though.

I'll ask them why they replaced them, but will have no way to test
whether it is reasonable or not.

Cheers
Glenn

It's hard for me to know what the customs
are in AU regarding repairs. In California,
the shop is required to give you the defective
parts upon demand. If the plugs looked good,
I'd not want to pay for new ones and if they
were bad, I'd be concerned that they didn't
last long. Perhaps you could get them to
charge you their cost for the plugs. Seems
like that would be fair.

Glenn Pure
Canberra, Australia
Web page: http://www.evans-pure.net