bugeyeblues

I have a 2.0L with a GT30BB and am right around 103k. Car runs great, but dissipates oil as quick as gas. I'm running ams 5-30 full synthetic. I will not be running this oil again, at least in this motor. I've been recommended to run 5-40 by a few people, which will make a difference but i don't think it'll be a critical difference. I was recommended by someone with much more knowledge than myself to try running conventional 10-40. I haven't done a leak down test, and don't want to until after I try thicker oil to see if it helps. Anyone have some recommendations or thoughts on the 10-40?

Subi3

iTrader: (1)

In my experience Rotella T6 5W-40 is the best oil in combating oil consumption/burning

bugeyeblues

That's the exact oil I was planning on trying next until I was recommended 10-40 conventional. Still at a dilemma..

Gancherov

iTrader: (13)

An oiling system should be a closed system. NO fluid is supposed to leak out. If you are losing fluid there are only a few options. It is either leaking from an old/damaged mating surface out of the engine (head gasket is the most common), leaking out from a NEW opening where oil does not normally travel, or being burned up either in the cylinders or turbo (which kinda falls into old/damaged mating surfaces, but differs in that the oil will not leave an easily visible trail).

Thicker oil would make it tougher for it to seep through the small passages usually found in old/damaged mating surfaces, which might reduce oil loss in types 1 and 3. Nothing short of plugging the hole will stop oil from leaking out if you have the 2nd type of problem. I would recommend getting an oil pressure gauge before playing with different viscosities, otherwise you have no data other than how fast 1qt +/-30% of oil disappears(y) from the dip stick over time(x). You want to see ~10Psi per 1000RPM, this would give you the correct thickness oil for your given motor including it's current condition. Using thicker oil to stop a leak is a poor stop-gap because you will have too much oil pressure at low RPM and the pump will not work properly at high RPM.

Given that you're at 103K miles, I would bet on a leaky headgasket or worn out oil control rings on the pistons. These are the common issues with this motor. It could also very easily be the interior turbo seals leaking and burning oil, but I can't speak to the service interval or wear level of your particular unit.

Check your radiator fluid. If it has no signs of oil in it then the headgasket is likely OK, but not for sure. You can then do a compression/leakdown test to check the rings/valves/head gasket seal together.

bugeyeblues

Yikes....turbo has a little over 3k on it. Don't think the seals are bad on that. Coolant is normal and I don't think I have smoke coming out of my exhaust. Well, I mean more than normal, I'm straight piped. Failing oil control ring was an initial thought....I suppose a leak down test would be ideal. I'm trying to avoid all that but looks like it might have to come down to it. What were your thoughts on conventional oil?

oaklandish_WRX

iTrader: (10)

Avoid conventional... a decent 40 grade synthetic oil is your likely answer, assuming your leakdown/compression are OK. Not all Amsoils are fantastic at lasting (i,e, not shearing and burning off). Which oil in particular were you running?

Checked your PCV lately?

Gancherov

iTrader: (13)

Conventional vs. Synthetic is a long and complicated debate that I'll boil down to one metric for simplicity's sake: oil change interval.

I have 7L of oil in my system and I change it every ~1500-2000 miles. I change it every 3 months or after ~4 hours or more of high-rev use, though i've had oil analysis done which showed I could probably wait safely until 4-5 months or ~3000-3500 miles.

I use conventional oil because it is cheap. Synthetic would have more additives to last longer, but that wouldn't be helpful to me since I'm going to change the oil anyway.

In your case... I would use mineral based oil until I found the leak (since I'm going to be adding more oil often I don't want to burn up expensive synthetic) and then once the issue was resolved I would try to find a synthetic that gives me a good balance of cost vs protection. I would run the cheapest/most available synthetic that comes back with a good oil analysis from Blackstone (I love that company!).

FWIW I think my car really liked Rotella T6 5w-40 in my 2L stock turbo configuration. It quieted down the valve tap sounds and didn't burn the ~1L/3000mi like the Mobile 1 5w-30 did. It is known that the Rotella T6 will wear out catalytic converters over some period of time, so that might be something to consider... but I doubt you have one. Also, it was available at Walmart for a reasonable price.

bugeyeblues

No. What will that tell me?



This was really helpful. I change my oil frequently even with synthetic, at least every 3k. I just need to find out where it's disappearing. Process of elimination. In the mean time i'm gonna run chevron 10-40 this next go around. I won't brush this off forever

oaklandish_WRX

iTrader: (10)

Pcv clogs and it forces crank case gases and oil past rings and valve seals = consumption.

Try valvoline hi mileage Syn blend 10w40: seal swellers and good viscosity. And on sale often.

bugeyeblues

I already but the chevron 10-40 in with a zinc additive. I'll try this oil and see how she responds to it. I bought a new PVC for about a buck fifty. I'm gonna put that in tomorrow. Thanks for info.

Heedz

iTrader: (51)

Buy some of the 15w-50 I use....

bugeyeblues

How's your car liking it? I change every 2-3k. I can't afford to run that stuff