AIR LOCK or HEAD GASKET?
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Scooby Regular
Joined: Oct 2014
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From: Southampton
AIR LOCK or HEAD GASKET?
2007 2.5 STI 26k
Was getting over heating intermittently recently so yesterday I had the thermostat changed for a Mishimoto cool running stat and a full coolant change for genuine Subaru stuff. Car is still over heating, but again very intermittently.
So I jacked the drivers side up, header tank cap off and heaters on full and hot. Let the engine tickover for a good 15-20 mins even with a little revs got the temp up to around 90oC. Left it running for a while, no coolant levels dropped and header tank was above half way anyway so no need to top up. Took the car for a drive, nothing too hard but a little boost here and there. Car sat at normal temp between 80-90oC for most of the journey (about 20 mins) then as I was coming back the temp raised to 114oC whilst driving, continued to drive and around 30 seconds later it dropped back to 96oC. Pulled up on my drive way and it then rose back to 114oC.
Does this sound more like air lock or head gasket symptoms?
Was getting over heating intermittently recently so yesterday I had the thermostat changed for a Mishimoto cool running stat and a full coolant change for genuine Subaru stuff. Car is still over heating, but again very intermittently.
So I jacked the drivers side up, header tank cap off and heaters on full and hot. Let the engine tickover for a good 15-20 mins even with a little revs got the temp up to around 90oC. Left it running for a while, no coolant levels dropped and header tank was above half way anyway so no need to top up. Took the car for a drive, nothing too hard but a little boost here and there. Car sat at normal temp between 80-90oC for most of the journey (about 20 mins) then as I was coming back the temp raised to 114oC whilst driving, continued to drive and around 30 seconds later it dropped back to 96oC. Pulled up on my drive way and it then rose back to 114oC.
Does this sound more like air lock or head gasket symptoms?
Do you know how they refilled? If you don't do it properly, it's dead easy to airlock it and there is NO KNOWN WAY TO BLEED IT.
Do a search in my name for how to.
Other things to consider:
Water pump: the impeller becomes adrift from the shaft so it won't circulate water.
As I said, if the stat goes, it's generally fail-safe, ie it will stick open and the car won't come to temperature. That's to stop it boiling.
Do a search in my name for how to.
Other things to consider:
Water pump: the impeller becomes adrift from the shaft so it won't circulate water.
As I said, if the stat goes, it's generally fail-safe, ie it will stick open and the car won't come to temperature. That's to stop it boiling.
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