Oil in coolant resevoir

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4onthefloor
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Oil in coolant resevoir

Post by 4onthefloor »

My car has been consuming a bit of oil lately. I was looking over it yesterday and noticed that the coolant in the resevoir was brownish and there appears to be oil residue on the inside of the tank.

This leads me to suspect a possible head gasket leak. This was a common problem on pre-2005 impreza N/As but it was deemed to have been sorted out by '05 and it doesn't usually manifest itself until after 100k miles, not at 58k like my car.

Although it's not unheard of on these cars, is there anything else it could be?

I don't want to throw parts and money at it if there is something else causing this.

TIA
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Re: Oil in coolant resevoir

Post by ClutchFork »

Scroll down to Lesson 5 "signs of coolant leak" at
http://www.machinerylubrication.com/Rea ... l-analysis
before you drain off oil see the Crackle Test, second paragraph under Measuring Water at this link:
http://www.machinerylubrication.com/Rea ... minant-oil

If a head gasket leak that is putting oil in the coolant, then water must be getting in the oil which will be very bad for engine bearings. Enough water will make the oil weird. Put a drop of oil from dipstick on spoon and put flame under and see if it crackles like water in it.

Other kind of head gasket leak is combustion chamber to coolant. In that case you start cold engine and almost immediately the radiator hose is pressurized.
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Re: Oil in coolant resevoir

Post by theholycow »

I was about to post to thank you for those links and then I saw my quote in your sig and LOL'd. :lol:

Anyway I like diagnostic testing like that, and I especially like DIY tests. Will I actually do any of it? Probably too lazy...but I can pretend I will!
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Re: Oil in coolant resevoir

Post by Rope-Pusher »

When I've seen water or coolant in the oil, it made the oil look like chocolate milk.
You can have a leak going in one direction only, if the pressure differential stays the same, but oil pressure at idle prolly won't be a high as coolant pressure coming off the freeway to idling in traffic.
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Re: Oil in coolant resevoir

Post by 4onthefloor »

I've been checking the oil and there appears to be no cross-contamination, but yes idle oil pressure is low.

I'm probably going to change the gaskets ASAP.
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Re: Oil in coolant resevoir

Post by ClutchFork »

theholycow wrote:I was about to post to thank you for those links and then I saw my quote in your sig and LOL'd. :lol:
I had to do it. It just struck me as such a right on statement. A guy at work told me your supposed to drive a stick so people think you are driving an automatic. Well you can, but it's not my desire.
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Re: Oil in coolant resevoir

Post by SonicHKS »

Headgasket. Depends on the engine and where the leak is, most of the time coolant ends up in the oil, but sometimes its just oil in the coolant.
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Re: Oil in coolant resevoir

Post by 4onthefloor »

I've looked it over and had a few others look it over as well. I'm leaning towards it not being a headgasket problem. There isn't any external leaks, and I don't have any other symptoms of HG leaks. I think the coolant just went sludgy. According to Subaru's maintenance schedule it's due for a coolant flush anyway.
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Re: Oil in coolant resevoir

Post by potownrob »

4onthefloor wrote:My car has been consuming a bit of oil lately. I was looking over it yesterday and noticed that the coolant in the resevoir was brownish and there appears to be oil residue on the inside of the tank.

This leads me to suspect a possible head gasket leak. This was a common problem on pre-2005 impreza N/As but it was deemed to have been sorted out by '05 and it doesn't usually manifest itself until after 100k miles, not at 58k like my car.
i remember reading something like this too, but then i found reviews for the newer imprezas mentioning head gasket failures. i know they did change the gasket to a better one, but the setup of the engine isn't conducive to long-lasting gaskets. IIRC, the 2.5 turbo engine was designed to put less stress on the gaskets.
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Re: Oil in coolant resevoir

Post by theholycow »

4onthefloor wrote:I've looked it over and had a few others look it over as well. I'm leaning towards it not being a headgasket problem. There isn't any external leaks, and I don't have any other symptoms of HG leaks. I think the coolant just went sludgy. According to Subaru's maintenance schedule it's due for a coolant flush anyway.
What other causes can you think of for sludge in the coolant?

The first time (or any other time) I changed the coolant in my Buick I didn't see any sludge, and I think that coolant had to be 10+ years old...possibly as old as 25.
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Re: Oil in coolant resevoir

Post by Rope-Pusher »

From a Mazada broad:
Image
I flushed the coolant over the weekend as well. I did 5 drains and refills. The original fluid was very dark, but I think that's how it comes from the factory.
I took some pics after each drain for comparison. I didn't take a pic of the 5'th drain as I could't find a clear plastic bottle , however the fifth drain was almost clear, with very slight hint of green, so it was good for me.

I decided to do this, as i wanted to convert to Zerex G-05, so I flushed it as much as I could.

Here are some comparison pics for those of you wondering how many drains & fills it takes to get most of the old coolant out.
Image
This one is against the sun, note that the original fill is very dark as there is very little sun shining through.
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