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Old 07-31-2012, 06:45 PM   #1
e5pr1t
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Default 2008 STi Oil Consumption Problem

So after 2 track days in May, my car was burning oil, avg 1 qt per 1000 miles. I took my car to cobb & did a compression test, it was 140 135 135 130. Looks ok, I then put in an air oil separator (crawford), and changed oil from Motul 5W40 to Redline 10w40, still burns about .4 qt after 400 miles of driving.

I check for any signs of smoke so many times, it DOES NOT smoke at all, no smoke from tail pipe, I removed the oil filler cap & let the car idle, then give it some revs, no smoke...compression was good...car feels strong, just goes through a lot of oil. Doesn't look like ringland failure to me...

Also what I noticed when I removed the TMIC & throttle body to install the AOS, there was only very little oil in the intercooler & throttle body. Any suggestions? Leaks maybe? Seafoam? Thanks for your input.
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Old 07-31-2012, 07:09 PM   #2
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it just hasnt actually blown up yet...this is classic symptoms of that
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Old 07-31-2012, 11:20 PM   #3
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Or valve seals could be seeping some or the turbo seals are starting to go. It could be the beginning of a few different things. According to Subaru 1 quart per 1K miles is acceptable.

Is this a stock engine? How many miles are on the engine? How long have you owned the car? What was the oil consumption previously?
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Old 07-31-2012, 11:45 PM   #4
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Originally Posted by Uncle Scotty View Post
it just hasnt actually blown up yet...this is classic symptoms of that

Thanks for another fantastic helpful and positive response.. god you're a tool.


@op, it could be multiple other things, If your that worried about it I would begin looking at things like turbo oil seals and valve stem seals. Have you checked all over the bottom of the car to make sure its not something simple as a leaky seal? Pull your cam covers to make sure the cam seals are not leaking.
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Old 08-01-2012, 12:29 AM   #5
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Originally Posted by VisBits View Post
Thanks for another fantastic helpful and positive response.. god you're a tool.


@op, it could be multiple other things, If your that worried about it I would begin looking at things like turbo oil seals and valve stem seals. Have you checked all over the bottom of the car to make sure its not something simple as a leaky seal? Pull your cam covers to make sure the cam seals are not leaking.
sweetie....go blow up yet ANOTHER motor and cry about it....somewhere else please
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Old 08-01-2012, 12:45 AM   #6
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A compression test doesn't tell the whole story so I would do a leak-down test too.
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Old 08-01-2012, 02:25 AM   #7
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A compression test doesn't tell the whole story so I would do a leak-down test too.
Yep. I've done many and have had quite a few cars pass the compression test but fail leakdown so I don't even bother just doing a compression test. A cracked ringland is a good possibility.
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Old 08-01-2012, 01:22 PM   #8
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Were you running Motul 300V 5W-40? If not, then the Red Line is a completely different type of oil and sometimes shows high consumption for 2-3 intervals. The RL 10W-40 will behave more like a 50 weight with its very high High Temp High Shear. It's even higher than Mobil1 15W-50.

Hopefully you don't have a mechanical issue.

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Old 08-01-2012, 07:03 PM   #9
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Try a normal 5w40 and how it does, if nothing changes id say ur turbo is on the way out. My old fp green was eatting 1qt every 700 miles. It was insane. Swapped in a dom 3 and it doesn't burn a drop
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Old 08-18-2012, 05:12 AM   #10
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Update...

After 550 miles of city driving from last oil change to Redline 10W40 the dip stick was right below the low mark, I added about 0.4 quart, so it shows slightly less than half on the dip stick. (The weird thing was, when I checked at 400 miles after the oil change, I had about half left on the dipstick, looks like the other half disappeared after 150 miles).

Decided to re-route the bottom hose of the Crawford AOS so now it goes down hill all the way (Before I followed instructions to route the hose behind the ac line, but then it'll have a kink).

Discovered quite some oil inside the bottom hose (orange) of the TMIC that goes to the turbo. However, there was nothing in the AOS hose. Only a little bit of oil inside the hose that goes to the throttle body. After some driving around, oil level came back up to about 70% on the dip stick.

After another 200 miles of city driving, oil went down to about 40-50% again on the dip stick. During this time, I finally discovered some gray smoke from the tail pipe under WOT in 2nd gear. I had a buddy following me & he said the smoke came out briefly after I got on gas & lasted for about 1-2 seconds. (I did this twice, first time there were more smoke, second time there was only a little bit) No smoke after that...and still no smoke at all in other conditions...

Today I took the car in for compression check & leak down test, looking for a firm answer, and the results are...

Mileage - 72700
1. 144 - 6%
2. 143 - 6%
3. 143 - 8%
4. 138 - 12%

Also the spark plugs are completely dry & perfectly fine (replaced about 2 months ago)

I wasn't too happy about the numbers on cylinder 4. It looks like cylinder 4 is slightly weaker but I got both reputable shops assure me the pistons are fine. Besides, cylinder 4 is usually the weakest according to my research.

I'm assuming if the car burns 1 qt every 5-600 miles or 1000 miles due to ringland failures...The car should smoke a lot, and I might even get miss fire codes...

Any suggestions? I'm leaning toward the turbo at this time, but should I completely rule out the pistons? I would probably still try to locate leaks with oil dye, and I may switch to Castrol Edge & see if that helps.

Thanks for your input.
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Old 08-18-2012, 05:50 AM   #11
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Your leakdown numbers look pretty good. I had a leakdown test performed before I bought my STI and the numbers were 5,5,7,10 so they're very similar to yours. The shop, a very reputable one, felt that up to 15% was ok.

I would unbolt the downpipe from the turbo and check for any oil leaks past the seal.
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Old 08-18-2012, 09:52 AM   #12
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My turbo had a slightly bent fin and was dry inside. Yet after swapping in a new turbo my consumtion stopped, thank god. Oil disappearing is really scary when u have no idea why.
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Old 02-03-2013, 10:57 PM   #13
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Here is my story. About a year and a half ago I bought my 2008 STi with only 29k miles on it. A couple of months later I noticed that the car uses more then normal amount of oil and started my own consumption log. It turned out to be about a quart per 800 miles. So I went to Carter Subaru here in Seattle and they could not find anything wrong and started their oil consumption test. In the beginning they confirmed my numbers but by the end of the test it was a quart per 500 miles. It was obviously getting worse and they took the car for compression - leak down test. Later that day they called me and told me compression was fine, but they were not happy with leak down results and they need to pull the engine out for close inspection. Fine by me, power train still on warranty. Next day they told me that #1 and #3 pistons had cracked ring lands and they pulled service history and found out that #4 piston was replaced at 500 miles for the same reason, plus cylinder walls were worn out of specs and I have less than 30% left on my clutch. Wow! Looks like previous owner had a lot of fun with this car. Their verdict was: the car needs a new short block (fortunately covered by warranty). I also opted to replace clutch, timing belt, PCV valve and hose and spark plugs at my expense. All said and done a week later it costed me 1200 bucks. Since that I only put 500 miles on it and honestly did not check oil level yet.

Last edited by Sakhalex; 02-03-2013 at 11:06 PM.
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Old 02-03-2013, 11:00 PM   #14
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That's good dude. Luckily u had ur warranty and they took care of u
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Old 02-04-2013, 01:27 AM   #15
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Quote:
Originally Posted by Sakhalex View Post
Here is my story. About a year and a half ago I bought my 2008 STi with only 29k miles on it. A couple of months later I noticed that the car uses more then normal amount of oil and started my own consumption log. It turned out to be about a quart per 800 miles. So I went to Carter Subaru here in Seattle and they could not find anything wrong and started their oil consumption test. In the beginning they confirmed my numbers but by the end of the test it was a quart per 500 miles. It was obviously getting worse and they took the car for compression - leak down test. Later that day they called me and told me compression was fine, but they were not happy with leak down results and they need to pull the engine out for close inspection. Fine by me, power train still on warranty. Next day they told me that #1 and #3 pistons had cracked ring lands and they pulled service history and found out that #4 piston was replaced at 500 miles for the same reason, plus cylinder walls were worn out of specs and I have less than 30% left on my clutch. Wow! Looks like previous owner had a lot of fun with this car. Their verdict was: the car needs a new short block (fortunately covered by warranty). I also opted to replace clutch, timing belt, PCV valve and hose and spark plugs at my expense. All said and done a week later it costed me 1200 bucks. Since that I only put 500 miles on it and honestly did not check oil level yet.

keep an eye on the oil level!!!!!!

and make sure ya do a good bit of running it under engine braking to seat the rings well...change the oil at 750 miles and 1500 and 3000
id use valvoline 10w30...and...

well....prolly wastin my breath here....
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Old 02-04-2013, 12:39 PM   #16
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Anything to do with oil consumption with wrxs/sti is 90% because of a faulty or failing piston ring or ringland if there are no leaks or anything else.
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Old 02-04-2013, 12:40 PM   #17
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Can't drive these cars like a Honda.
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Old 02-04-2013, 05:56 PM   #18
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Quote:
Originally Posted by Uncle Scotty View Post

keep an eye on the oil level!!!!!!

and make sure ya do a good bit of running it under engine braking to seat the rings well...change the oil at 750 miles and 1500 and 3000
id use valvoline 10w30...and...

well....prolly wastin my breath here....
Listen to this guy and never assume that your levels are fine.

-Dennis
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Old 02-04-2013, 08:28 PM   #19
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Time to sell!
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Old 02-05-2013, 04:15 AM   #20
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1200?!?! Dealership clutch job with new flywheel is 1800-2000 in northern Cali
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Old 02-05-2013, 06:34 PM   #21
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Originally Posted by Crobb707 View Post
1200?!?! Dealership clutch job with new flywheel is 1800-2000 in northern Cali
I just got lucky. Since they pulled the engine out anyway, they only charged me cost of parts, no labor.
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Old 02-26-2013, 01:53 PM   #22
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Guess I haven't updated in this thread. Oil consumption got worse to about 1 qt every 400 miles. In the end I decided to do a full engine rebuild. Cobb did it for me w/all the forged intervals, JE Pistons, Manley Rods, ACL main & rod bearings, Killer B Oil pick up, ported heads, machine work, at the same time replaced a bunch of wear and tear items including the clutch.

Alan
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Old 02-27-2013, 10:06 PM   #23
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Nice!
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Old 02-28-2013, 03:10 AM   #24
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Quote:
Originally Posted by e5pr1t View Post
Guess I haven't updated in this thread. Oil consumption got worse to about 1 qt every 400 miles. In the end I decided to do a full engine rebuild. Cobb did it for me w/all the forged intervals, JE Pistons, Manley Rods, ACL main & rod bearings, Killer B Oil pick up, ported heads, machine work, at the same time replaced a bunch of wear and tear items including the clutch.

Alan
So did Cobb say whether it was ringland failure after all, like #4? Glad to see you got it fixed.
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Old 03-01-2013, 04:21 AM   #25
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Quote:
Originally Posted by VisBits View Post
Thanks for another fantastic helpful and positive response.. god you're a tool.


@op, it could be multiple other things, If your that worried about it I would begin looking at things like turbo oil seals and valve stem seals. Have you checked all over the bottom of the car to make sure its not something simple as a leaky seal? Pull your cam covers to make sure the cam seals are not leaking.

Uncle Scotty is a lot of things..... a tool.. he is not.


don't call him that.
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