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mechdoug

oil in coolant can this be a head gasket?

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could be a couple things, head gasket seems most likely.

 

has it ever overheated, every notice any loss of coolant or antifreeze? has it ever had any major engine work....the more specific details like this the better for diagnosing a car without ever seeing, hearing, touching, or smelling it!

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oil in coolant can this be a head gasket? or is it worse? 96 legacy outback 2.5 auto 165000 miles

How much oil?

 

Oil is less likely to get into coolant than coolant into oil, and is less of a problem.

 

Coolant in oil creates emulsion and can compromise bearings.

 

The dark crud in the coolant is likely NOT leaking oil. More likely it's debris from minor internal corrosion of hoses..

 

When a headgasket goes bad, exhaust from the cylinder gets intot he coolant and makes the overflow tank bubble when running. Eventually the failure will result in misfiring. If the HG failure is close to oil and coolant passages, the high pressure of the coolant can push into the oil passsage and create a green foamy mix visible on your dipstick.

 

However, the Phase1 DOHC (96-99) is known for HG failure (20%). The symptoms I don't really know, other than bubbling coolant.

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good point UB - how do you know there is oil in the coolant? dark stuff in the overflow reservoir doesn't really mean much. more info!

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On an DOHC 2.5L, dark, oily substance in the over flow bottle is a sure sing of head gaskets leaking. It is not really oil, it is a mix of carbon and unbrunt fuel from combustion leaking into the cooling system.

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could be a couple things, head gasket seems most likely.

 

has it ever overheated, every notice any loss of coolant or antifreeze? has it ever had any major engine work....the more specific details like this the better for diagnosing a car without ever seeing, hearing, touching, or smelling it!

 

Wifes car. Said she got to the corner 1 mile away from home and engine sputtered or back firedand the check engine light came on, so she drove it back home and parked it. I came home read the codes (2) cyl 1 missfire. Cleared codes started engine seemed OK. Next day she drove to work 15 miles everything OK, drove home to drop off a kid then headed out again 12 miles or so got to stop sign smoke coming from under the hood. Checked under hood left side of engine compartment and wheel all wet. She drove 1 mile to my dads and called to say she had coolant all over under the hood and drivers tire. I filled the radiator and overflow tank and found dark grey stuff floating to the top of the coolant. Overflow hose fit very loose to the radiator.

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most likely head gasket - coolant bubbling out the overflow is very common.

Does the head gasket explain the oil too! Maybe the gasket is damaged where the oil passages are to the head?

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Does the head gasket explain the oil too! Maybe the gasket is damaged where the oil passages are to the head?

 

On an DOHC 2.5L, dark, oily substance in the over flow bottle is a sure sing of head gaskets leaking. It is not really oil, it is a mix of carbon and unbrunt fuel from combustion leaking into the cooling system.

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A quick, easy check for HG's.

 

1. Make SURE the coolant is absolutely full.

2. Start the car & let get up to temperature at idle. Wait until the fans cycle on at least the first time.

3. Open overflow tank, and observe. If you see bubbles, close the tank lid for 15-20sec, then reopen & sniff. If the tank smells the same as the exhaust, then you've blown the HG's. Trust me, you can smell the exhaust in the tank, if it's there. If there aren't any bubbles, then there probably will be soon.

 

Unfortunately your symptoms are the same as mine, a greasy, black film in the overflow, and blowing coolant everywhere.

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Thanks for everyone's input!

Looks like I'll be pulling the motor and adding a gasket set.

What do you suggest flushing the cooling system with? Where is the best place to buy a gasket set?

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heagaskets ONLY from subaru.

 

Flush out the radiator first, as soon as you remove it. Other wise oil + antfreeze + air = gum

 

Also do yourslf a favor and clean out the overflow ( no one does it).

 

 

nipper

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