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Discussion Starter · #1 ·
**** of a first post I know.

Bought the car about a month ago, the car had a service history which includes a complete replacement of head gaskets (and rings/pistons) at 98,000km.

The odometer is currently sitting at 168,000km. I watched the temp and coolant like a hawk since I've had it. Missed a few days after a few hundred km trip and my coolant was low. Took it into the shop today for a pressure test and they diagnose the problem as a leaking headgasket. The mechanic said the pressure would build up high (I think 80 was the level he quoted) and then drop down in a couple of minutes. The car has not overheated, and I've seen no blue/white smoke (although lots of grey smoke when cold). No smell of coolant in car and no issue with the heat. No puddles when parked either.

The last job he did was roughly 1400 plus another 300 for the heads to be machined. Not a horrible price for the job I know.

Could this potentially be something else? Is it worth putting some Subaru coolant conditioner into the system? Or am I just asking for more trouble?
 

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Putting pressure on the cooling system and finding it drop could be a leak in a hose or at a hose clamp, a pin hole in the radiator, etc. Just because the pressure drops does not mean it's the head gasket.

Was that 80 psi or kPa? I hope the latter, because 80 psi on the cooling system would probably cause leaks that normal operation would not. (Normal cooling system pressure is around 12 psi.

How low was the coolant and was that in the overflow reservoir, or in the radiator itself?
 

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Discussion Starter · #3 ·
Coolant got down to the low mark when cold, was typically at the high mark. I did notice bubble in the overflow tank when I shut the car down as well.

Perhaps I should take the car for a second opinion
 

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Another way to check for the dreaded head gasket issue is to smell the fluid in the overflow coolant reservoir. If it's a head gasket the coolant reservoir should smell like exhaust.
 

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2005 LL Bean
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You can have the coolant tested to see if there are signs of combustion emissions. From what I've read/heard, that can sometimes be the only way to diag a Scubie HG leak. Loss of coolant does not immediately mean a failed gasket. When the work was done before, was it done at a shop or by an owner? Also, was there a reason they did the piston/rings etc.?
 

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It would help to clarify- did the mechanic pressurize the cylinder for a leakdown test, or did he pressurize the cooling system? These are two different tests for different situations. 80psi into the cooling system would be a bad thing. 80psi into the cylinder would be a good starting point for a leakdown check.

Yeah, there are chemical tests that can detect exhaust gas in your coolant. And these tests are not infallible, but if done and interpreted correctly they will nicely shore up other indications.
 

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1993 Legacy LSi with still functioning Air Suspension, 1999 Outback 2.5L 5MT lab Rat
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Ouch 80 psi, I doubt the Radiator would survive ,let alone any hoses with any mileage on them. I have had a couple of head gaskets leak into the cylinder(s) cold which is usually accompanied by a cold misfire, that usualy goes away warm. In this condition it actually consumes coolant which is Very bad for the Catalytic Converter 80 psi during a Cylinder Leakdown test is adequate, during any Leakdown test I perform I look for bubbling into the cooling system indicative of air from my leakdown test getting into the cooling system. Also on your question about a second opinion, might not hurt since you may be facing some expensive repairs.
 

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Discussion Starter · #8 ·
Cooling system was pressurized. I'm thinking maybe he put it to 18, the mechanic sounded Scottish.

Engine work was done due to customer complaints of piston slap sound when engine was cold. Everything was done at the dealer under warranty.

To check for bubbling, should I look into the overflow or open the rad cap (when the car is just turned on)?
 
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