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2011 STI 7000miles - Burning Oil and Sludge on Oil Cap

8K views 14 replies 13 participants last post by  TonyT 
#1 ·
I just checked the oil, as I have been doing about every 500miles today. I always check my cars pretty regularly and around 2000 miles I had found the engine a quart and a half low. I took the car in and they said it was just due to break in. So I did not worry about it and moved on. At 3500miles I changed the oil and it was still full when I did.

At about 4500 miles I ordered installed a Perrin Catted DP, Perrin Tune via AP, Heat Shield and Perrin Turbo blanket since it was not losing any oil since 2000 miles.

Since then I have been checking and there was really no change, that is until today. Again I am a quart and a half low but when I pulled the cap I found a TON of sludge in the filler neck (Sorry for the bad photo).

I will do a compression test and coolant pressure test this weekend and monitor but even if I pull all the aftermarket I think I am screwed if there truly is an issue.

I have never heard of issues with antifreeze in the oil but now I am concerned that I might have a bad head gasket already. Any input would be greatly appreciated.
 
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#2 ·
are you low/losing coolant as well? otherwise no reason to do to any coolant system test. That "sludge" is normal build up, its basically oil that has sat with water in a cooler temp (by cooler i mean less than engine operating temp). When i removed my filler neck for installing my fuel injectors i had similar build up at the bottom of the tube. So dont be scare by it. It just looked like when the oil was changed some pooled on top of the filler

Also what kinda of oil are you using, IMO (i dont want this to turn into a oil thread) if its oem subaru oil, and youve run it for 3500 miles its too long and will start to burn up. Get something higher quality and it should get rid of most of your oil issue. The problem with oem oil is it shears very quick, and when it does it gets thinner and thinner, leading to oil burning/blow by.

Oil in antifreeze is pretty obvious if you were to drain your rad, but theres nothing here to suggest thats as an issue with your car.

Basically:
Switch oil to another brand (rotella t6, motul, redline are all popular choices)
and dont worry about that yellow sludge much. We all get it sadly.
An AOS reduces oil consumption obviously, but if there is a real problem (which from what youve said/shown, there doesnt seem to be) it just acts as a bandaid
 
#5 ·
#4 ·
Lol no its not your head gasket. For one the Perrin tune has been known to knock for a few people. That should be taken off. Two what oil are you using? This is very important in the STi. More so than any other car I think.
 
#6 ·
How much oil are you putting in at your oil change? I have used 5w40 Red Line in all 3 of my Subies without oil burning issue. Firm believer that 5w30 is too thin for these engines. 31k on my 2011 without issues.
 
#7 ·
I too always use redline. 5w30 for 40k and 5w40 for 5k and never a loss! Not even a drop. However I never started turning hard till resently. Turning hard will puke oil out the valve head breather lines. Without a AOS you will lose that oil and burn it up.

So another Q for you, been turning hard right before you noticed the oil losses??
 
#8 ·
If you haven't been burning oil, and all of a sudden have some missing first thing to check is the oil filter and drain plug. If you reuse the washer too many times it starts to seep at the drain plug. Also the washer sometimes might get tightned down off center a tad and seep as well.
I also have terrible luck with after market oil filters seeping, the only one that I've found to work for me are the mobile 1, synthetic media filters. I tried ~3 other brands and they all seeped iuncluding purolator, acdelco, and another one.

As stated before, that yellow goo is just water condensation and oil mixed together and the oil filler tube doesn't really get hot enough to evap the water as easily. So the remaining little bit of oil that doesn't drain down just sits there.
 
#9 ·
I just checked the oil, as I have been doing about every 500miles today. I always check my cars pretty regularly and around 2000 miles I had found the engine a quart and a half low. I took the car in and they said it was just due to break in. So I did not worry about it and moved on. At 3500miles I changed the oil and it was still full when I did.

At about 4500 miles I ordered installed a Perrin Catted DP, Perrin Tune via AP, Heat Shield and Perrin Turbo blanket since it was not losing any oil since 2000 miles.

Since then I have been checking and there was really no change, that is until today. Again I am a quart and a half low but when I pulled the cap I found a TON of sludge in the filler neck (Sorry for the bad photo).

I will do a compression test and coolant pressure test this weekend and monitor but even if I pull all the aftermarket I think I am screwed if there truly is an issue.

I have never heard of issues with antifreeze in the oil but now I am concerned that I might have a bad head gasket already. Any input would be greatly appreciated.
If your head gasket was bad, you'd notice your coolant temp gauge rising above middle, and when it really gets bad that needle will get really close to the red-zone and maybe even sit there.

There's an oil thread here with a long informative write-up about the nature of oil and why you should choose certain weights and can give you enough knowledge to discern through the common myths and misconceptions of motor oils.

I've, too, had mixed results with oil loss and my car. I noticed that when I drive the car with more aggressive driving habits: max boost at high rpms, cornering with lots of throttle, and such, that during a period of time when the oil was fresh, I didn't lose much (noticeable by eye measure) oil. However, After a period of time, then there'd be a gradual, to sudden increase in loss of oil. Hypothetical example....

Fresh Oil Week 1 - 5 qts
Week 2 - 5 qts
Week 3 - 4.7 qts
Week 4 - 3.8 qts

I also noticed that different oil brands would fair differently. Some would be consumed more quickly than others. My current working theory is that the additives breakdown over use and time, and combined with applications in motors with increased torque and temperature, then the additives will break down at an increased rate. The rate of breakdown increases over time & use. With less additives present, blowby increases.

I read a thread on here where someone performed research to show the quantity additives and minerals present in several popular blends, and also other values that was helpful for me in choosing oils. The oils with the less additives, I consumed more quickly. The oils with more additives and other supporting minerals and composition qualities, lasted longer periods of time before I needed to add oil.
 
#10 ·
Wow, what great responses, You guys are great!!!!!!

Let me see if I get all the questions answered here.

1.) I have had the dealer change the oil (I got some free oil changes). So I am assuming they used the recommended Subaru 5w/30 synthetic blend. I had planned to take the car in for oil changes in the hope that they would be more sympathetic is I paid them to do all the recommended services and established a relationship with them. However on my other boosted cars I have run 0-40W Mobile "European Blend" which has elevated levels of ZDDP and prefer Mobile 1 or K&N Filters (Made at the same factory(

2.) As for the Perrin tune I was over boosting to 21PSI on S# and seen as much a 3deg of Feedback knock. I would with them to get new/modified maps and still had issues. So I downloaded the Cobb Stg II ACN91 LWG and hold boost much better but am still seeing a bit of Feedback knock at 3,000RPM ish at WOT in both Sport and Sport Sharp. Trying to get into the tuner but he has been booked for over a month.

3.) What has me puzzled about the oil loss is that my wife’s driving habits don't change and she does not run the car hard what so ever. So why when the oil is new there is no loss then all the sudden it loses a huge amount???? There is are no leaks so the only way it is leaving the engine is through the exhaust and there is never any smoke.

4.) As for the sludge, I did see MANY posts and see that this is common. I did check the antifreeze and it is dead on full hot when warm so I doubt it has been consuming antifreeze!

So solutions so far are to get a catch can A/O separator, I like the design of the Crawford, it seems to be well thought out.

Monitor the oil consumption and try different oils

Cancel all my tuners appointments and get me car on the dyno ;-)
 
#11 · (Edited)
Without any doubt in my mind My wrx or sti never burned any fresh oil. Not on the track or anything. I don't drive much but I drive most every day. I changed my oil after almost 5 months and a winter cause I was starting to see oil consumption even if i wasn't going balls out on the car. I used about 1/2 a quart of oil from 1250-2250 miles, on my oil, in the last 6-8 weeks it was in the car. Since my change i have 350ish on it and haven't used a drop. I took photos of the stick and its IDENTICAL.

I am fairly sure between breakdown and moisture that is accumulated in the oil based primarily on time and temps that it very negatively impacts oil consumption in these cars.
I run redline 5-40. I tried t-6 and had about 1/4 quart of consumption but i didn't have it in the car as long either. I plan to change my oil every 3 months independant of mileage from now on and assume i will have no oil consumption that requires adding oil.
 
#12 ·
I agree on using a different oil.

I was burning to a quart oil left. Dry dipstick. Ever since I was off mobil 1 and onto subaru own branded it was gone. No more burn so far. about 400 miles since.

getting a AOS would be a great idea to lower the chances of slug forming. I'm investing on one myself.
 
#13 ·
I agree on using a different oil.

I was burning to a quart oil left. Dry dipstick. Ever since I was off mobil 1 and onto subaru own branded it was gone. No more burn so far. about 400 miles since.

getting a AOS would be a great idea to lower the chances of slug forming. I'm investing on one myself.
So you saying that with mobil 1, u did burn to a quart of oil betweem oil change? Damn..

I own a 06 sti and been using mobil 1 since i have it and no buring oil. Mobil 1 is what my dealer is using.

I guess all our car are very different. Could the weather be a factor?
 
#14 ·
The fact that you burned an unusually high amount of oil and then decided to mod doesn't sit well with me.

Don't trust the dealer. I, too had a free oil change, and they used Cam2 5W-30 mineral oil, which I would not recommend using past 3k miles.

I add 5 quarts at every oil change, using everything from the lowly Cam2 to Amsoil to Rotella T6, and the full hole on the dipstick has been filled every time I check the oil for the past 50k miles.
 
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