98 Outback overheating problem

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).

  1. 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.

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

  1. 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:

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Glenn Pure
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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

Reply to
Mickey

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.

Reply to
johninKY

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

"john>As for where the coolant went, it's a pressure differential thing. The

Glenn Pure Canberra, Australia Web page:

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Glenn Pure

The "cooling system conditioner" is for HG weeping and will not cure a blown HG. Sorry. "Glenn Pure" wrote in message news: snipped-for-privacy@4ax.com...

Reply to
Edward Hayes

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

"Edward Hayes" wrote:

Glenn Pure Canberra, Australia Web page:

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Glenn Pure

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

Reply to
Danny Russell

Please let us know what happens.

Reply to
rajp53

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

snipped-for-privacy@aol.com wrote:

Glenn Pure Canberra, Australia Web page:

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Glenn Pure

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

Reply to
hippo

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

Glenn Pure wrote:

Glenn Pure Canberra, Australia Web page:

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Glenn Pure

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.

Reply to
GrumpyOldGeek

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

GrumpyOldGeek wrote:

Glenn Pure Canberra, Australia Web page:

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Glenn Pure

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