Adis

Don't know if it's engine oil, SC oil, AC oil, or power steering fluid, but it's all over my engine bay. Can't make out a color, just dirt! Seems to be concentrated by the SC air filter. It's heaviest on/in the SC air filter and on the front of the AC condenser around the filter (see pic), but that could just be because it's sucking the stuff in. It's also along the bottoms of the SC inlet duct, and head unit. It seems heavier on the front face of the AC condenser, versus behind, but that could be an optical illusion since the dirt in all the oil is mostly on the front face, and there's plenty of oil behind the rad in the engine bay along the top of the steering rack, etc.. No leaks from the block/oil pan that I can see - looks real clean. Seems to be spraying out, or leaking near some source of air pressure that would blow it all over.

Car is a 2010 GS, ECS Novi 1500 with 1800 miles (1500 SC'd), regularly driven hard, but rarely into boost over 5 lbs. Oil pressure is normal (although a bit high i think.) I haven't installed an oil catch can, and I don't think one comes with the ECS package. SC oil level is high operating range, although it has blown off fluid over the miles. AC is still blowing cold (but I can't tell if the compressor is engaging.) Power steering fluid reservoir is covered in oil and level is too high.

I did some cleaning and inspecting and can't find a source: busted hose, loose clamp, etc. My first thought is a blown seal in the PS pump or reservoir since it's overfull, and the SC air inlet has been sucking it through the backside of the radiator. Or maybe the engine is burping oil through the crankcase ventilation system (is this possible?) But who knows? I thought best pose the question to the FI crowd, in case it's a common occurrence with SC'd cars. Are there any common places to look first? TIA - mark

Looking from top down pass side (SC air filter removed)


drivers side top


underneath driver's side (I cleaned a bunch of gunk off, but you get the idea...)

Motorhead-47

Looks to me like you are pumping oil up into the air bridge and it's running down/out the air filter.

Is this a dry sump car?

Adis

Thx for the reply. Yeah, it's a dry sump LS3. It's a completely stock motor. Could the SC be blowing off oil? There's only 4 oz of oil in that thing and it looks like there is 4 oz of oil in my engine compartment - so I don't think that's it.

Motorhead-47

Call ECS and show them these pictures. Ask them how they are plumbing the dry sump LS3's crankcase ventilation.

Adis

OK, i could really use some help with this one. I took the GS out again to heat cycle my new Toyos on the hot highway asphalt. After 20 minutes at 90-120 with a few short pulls at low boost, I stopped to check the tires and engine, and the whole front of the engine bay is again coated in mystery oil. It's lightly golden colored, and looks dirty or burnt (like engine oil) but doesn't seem as heavy as engine oil, so I'm pretty confident it's not SC oil or trans fluid (both red with distinct smells). The tuner installed a small PCV catch can, and I can't think of any place where engine oil would blow out that would make the kind of oil pattern I'm seeing since the GS doesn't have a EO cooler in the rad. Based on where the majority of gunk is (around the pump/steering gear/rack, i think it's PS fluid, which it could easily be since somewhere between the factory-dealer-tuner the PS reservoir got overfilled by at least 80 ml (car has less than 2K miles.) The puzzling thing it that the oil is also all over what I'll call the cooling section of the nose. The air filter (which is low on the pass side - opposite the PS pump/reservoir and in front of the rad) AC condenser, bottom of the rad, etc. I pulled the SC intercooler and the BOV filter is covered, and mysteriously, there is a pool of oil INSIDE the bottom of the intercooler, but none in the top (going to the manifold.) If the PS reservoir was overfull, and it boiled over on a hot, fast driving session, would the spray pattern get all over the cooling section of the car, and how did it get into the intercooler? I could see how PS fluid spraying out of the reservoir would get blown backwards from the rad fan, but how is it getting in front of the rad and onto the air filter? And how is it getting into the intercooler, isn't that constant positive airflow (bottom to top?) From the oil pattern, does this indicate more a blown PS pump seal or burst line (lower in the engine compartment) versus oil blowing out of the reservoir (higher in the engine compartment.) The PS is still working, and a visual inspection doesn't turn up and blown hoses/lines. The leak seems to only occur during high temp/high rev driving, and doesn't leak sitting or cold, or even low-load driving for that matter.).

Any thoughts are greatly appreciated since I have no warranty, and wouldn't have a trustworthy mechanic to look at it even if I did.

gotjuice?

Too much crankcase pressure. Check valve working correctly? Isolate and vent to atmosphere and do a run to recheck. Make sure the check valve is working correctly, Most use a very cheap unit.

Adis

Juice, thanks for the reply. The crankcase vent hose from the oil tank is routed to the air filter element. Could the oil be coming from there? That would explain how the air filter and front of the engine bay is getting soaked. I don't see a check valve in either the the oil tank to intake/air filter hose or in the valve cover to oil tank hose. Is there a valve in the oil tank? Actually, what's going on inside there anyway? Does the oil tank act as a catch can?

EDIT: OK, so I found the check valve, inline in the PCV dirty air hose. And this has proven that the oil in my intercooler, and which is all over my engine bay, is definitely engine oil. I'm not quite sure how the PCV system is plumbed. Dirty air from the valve covers is pushed into the oil tank, where it presumably evaporates oil, then clean(er) air is pulled from the oil tank with vacuum from the air intake duct (which has been rerouted to my air filter.) How does the PCV dirty air hose (between the valley cover and TB, which includes the check valve) fit into this system? And, could a faulty check valve cause oil from the oil tank to be sucked into the air filter (or blown for that matter...?) When I suck on the check valve it shuts, but not completely, maybe 85% shut (I know, not very scientific.) Thanks again.

EDIT EDIT: I know this is stream of consciousness foruming...but I just thought about it. At the air intake, boost is pushing air, not pulling...so if the check valve is not fully closing, pressurized air is being pushed back through the check valve, into the engine block valley, causing the increase in crankcase pressure. This increases the pressure through the hoses out the valve covers and to the oil tank, which on the other side is also experiencing greater vacuum from the hose from the air filter. This causes oil from the tank to be both pushed and pulled into the air cleaner, which then runs out into the front of my engine bay. Going 150 mph, the airflow through the fascia, along with the draw from the radiator fan, pulls the running oil all over the front of my engine bay, and I have a big mess. What do you think, have I been breathing too much brake cleaner?

FINAL EDIT (I promise): Even if the above is the case, what I don't get is how did about 2-3 oz of engine oil get into the intercooler? Does the BOV pull air?

bullitt4110

Did you happen to just change your oil? Ive seen that happen when to much oil was added to the dry sump. Just a guess, but check your oil level.

Adis

No the car is essentially new, I just broke 2000 miles (300 miles break in, and 600 miles driving to and from the tuners.) So, I haven't changed the oil yet, although I did add some to get it to the high end of the operating range. Once I get everything put back together, I'll definitely keep it in the middle of the operating range.

Streetk14

I remember a lot of Z06s (even stock ones) having problems with oil entering the air bridge - and I think your dry sump system is the same. I think you are on the right track. I'm guessing it's engine oil being sucked or pushed out of the oil tank and into the air filter. It accumulates, then drips out of the filter and gets blown around by air turbulence at speed.

This also explains the oil in your intercooler. If it is getting inside your air filter, then it's getting sucked into the blower. It is then probably going to pool up at the bottom of the intercooler. Have you taken the air bridge and filter off yet? I'm guessing you'll see oil in the blower inlet/impeller area. It could be a crankcase pressure problem (bad check-valve) or that the oil is just over-filled. I could have sworn reading that a lot of guys would run the oil tank at a lower level just for this reason.

You could also look into doing a catch can for the fresh-air side of the PCV system - but I would make sure everything else is working properly first. There is a vendor on here selling a really nice looking catch can that has 2 valves built in and is designed for use with a centri blower: http://forums.corvetteforum.com/c6-t...-catchcan.html

Also some good information in there about PCV systems in general. Might help you out some.

The Bat Car

More details on the Turbo/SC dual valve need


Here are the challenges:
*
Normally, an engine crankcase is evacuated of the harmful combustion byproducts through the use of the intake manifold vacuum. This is at its greatest while at idle, or when decelerating from WOT so this, as long as the flow is regulated (usually by a PCV valve or a fixed orifice) this effectively keeps a constant cross flow of filtered fresh air through the crankcase where it is evacuated.
*
With a turbo charged, or front mount super charger presents a few issues. First, when the intake manifold is pressurized, there is no longer a vacuum source to deal with the combustion by-products, etc.
*
And second, the pressure from the intake is pressurizing the crankcase resulting in less power from the pressure, (breathers alone will release excess pressure, but do not allow the crankcase to be "flushed")*and oil leaks are not uncommon.
*
The dual valve oil separating can has nearly 9" between the inlet & outlet of the can allowing maximum oil separation & containment. The avg can has app. 1-3". This makes it possible for some oil to be pulled through the avg catch can no matter how well it catchs oil.
*
When the engine is at idle & non-boost operation the main check valve is open and using the intake manifold vacuum for crankcase evac. As soon as the intake is pressurized from boost, the main check valve closes so there can be no back-flow through the can & thus pressurizing the crankcase, and the second valve opens and uses the inlet side of the head unit as a vacuum source (as most kit instructions have you run the evac for all modes of operation) so no matter what state of boost or non-boost the engine is in, it always has positive crankcase evacuation taking place.
*
The can is 3-4 times the capacity of the small ones which not only aids in no oil pull through, but rarely needs emptied except at normal oil change intervals.







Hope this helps.

Adis

Thanks for the advice, Streetk14. I've taken out the intercooler, charge tube, and rad for inspection and cleaning (already used about a case of brake cleaner and a bottle of Dawn!) From what I can tell, the head unit is clean both in and out of the impeller. At least at the inlet/outlet ports. There was some oil pooled in the lower IC inlet hose, but not as much as in the IC. There is a small streak of oil pooled in the bottom of the charge tube going to the manifold and inside the manifold there is also a sheen of oil with a quarter-sized pool just inboard of the TB. So, some oil is making it's way into the engine, but it looks like most of it is condensing at the bottom of the IC. It's just that there was so much oil in the air filter, the IC and out in the engine bay - all told maybe 3-4 oz total - with relatively little in the head unit and manifold, and all this from a few 30 minute driving sessions (maybe 500 miles total) that it's hard for me to imagine it's a build up of oil vapor over time. It seems more like a barf of oil from overpressure under boost. But if the oil is getting burped into the air filter, and there is a significant pool in the IC, wouldn't there be more traces of it in the head unit? Another mysterious thing is that i checked the oil tank to air filter hose with a q-tip in two places, and the line appears to be oil-free, as does the vacuum line from the IC BOV to the brake booster...? I just can't think of any other way that oil is getting where it's getting, other than from the line between the oil tank and air filter.

Bat Car, I've read your posts (good write-up) and am pretty much sold on the dual valve catch can. I just want to have a complete understanding of what's occurring in my engine before I spend money on a solution. I tried to call Byun Speed yesterday and today, but no answer. Please PM me so that we can get in touch.

Thanks again, everyone, for taking the time to help.

The Bat Car

I would do a leak-down test on #7 first (usually the leanest and first to sustain damage) to see if you have a piston/ring/cylinder issue. Not a compression test as that wont tell alot. But any FI build will have more blow-by and crankcase pressure then a NA build....and the more boost the more likely your not able to deal with it as most FI kits only address 1/2 of the issue. If your useing the valley cover for evac the fixed orfice is not large enough for the amount of flow needed to deal with the added pressure. We prefer evacuating from the rear of the drivers side valve cover and capping the valley. This allows for a good cross flow of fresh air to "flush" the crankcase of the nasty combustion by products.

Seeing as your air filter was soaked, when the checkvalve closes the crankcase has no place to relieve the pressure so it back-flows into the air filter as this is usually where the fresh crankcase make up air is drawn on most kits.

If you just vent with breathers, you will relieve the pressure, but every time you shut down & the engine cools the flashed off compunds that you dont want in the crankcase recondense and contaminate the oil & coat the internal parts with corrosive compounds.

Ask me any details you need and I will do my best to guide you through this as I deal with this almost daily in one form or another. We have several 1000-1200 hp FI builds and done correctly, you wont have any issues (unless of course there is a mechanical defect/damage.). I do see far to often damage to a ringland or piston from detonation (believe it or not some tuners desensitize the knock sensors or have the timing returned to quick).

Streetk14

Good advice - I'd probably test the check valve with a pressure/vacuum pump and do a leakdown test. Maybe the check-valve is installed backwards? Just throwing out ideas.

Might want to also drain some oil out of the oil tank to see if that helps. Good luck with it....

The Bat Car

Didn't think of the checkvalve being backwards....that would cause the symptoms as well.

Adis

OK, if I understand this correctly, I either have too much oil in the tank, a bad PCV checkvalve, or piston/ring damage, or a combination of any/all 3, correct? So what I'm going to do is:

1.) Clean and reinstall everything (is there an effective way to clean the intake without removing it?)
2.) Replace the installed PCV check valve with a better one that I know is closing completely, any recommendations?
3.) Drain engine oil to the low side of the middle of the operating range.
4.) Do a valve cover oil filler test to see if I can feel pressure which may indicate reversion from piston/ring damage.
5.) Put the engine in boost to see if it is still blowing oil as a result of crankcase overpressure. If the check valve is working properly I shouldn't have any overpressure.
6.) If no oil burps, install dual valve catch can to protect engine from accumulated oil vapor fouling.
6.) Get some hard miles on the car, then inspect intake for oil that would indicate piston/ring damage.
7.) If oil in the intake, do leakdown tests on cylinders.
7.) Hope for the best...

Just for clarification, have I got the dual catch can routing correct on this drawing (It's just my best guess from what I've read in other posts):



the thing I'm not really sure about is where does the hose from the back pressure outlet side of the can (red color in the chart) get routed to, someplace in front of the SC head unit?

Again, I can't thank you guys enough.

The Bat Car

Correct. The red line needs to go as close to the inlet of the head unit as possible where the suction is the greatest under boost. I would go one step further and have the frsh air come from a stand alone checkvalved breather mounted on the pass side of the radiator and plug the air filter hole, but it will still work fine as shown unless your "burpping" oil from the tank.

Wish you were close enought to come in I would help get it figured out. Just ask if you need anything else.

Adis

Umm, bad news for me I guess. I reinstalled everything, and drained some engine oil. I pulled the PCV inlet hose from the air cleaner to the oil tank and routed it to the back of the engine compartment with a catch can (OK, it was a coke bottle...) to grab any oil blowing by. I took the car out for a test drive. About 45 minutes in slow stop and go city traffic. No apparent oil leaks. Then i took it out again for harder driving. About 20 minutes or so, a few quick starts, nothing over 5500rpm, and no real pulls into boost. But there is oil in the intercooler again. The oil is getting into the engine bay from the IC BOV that is located on the driver's side of the IC. What I don't understand is how is the oil getting in there? No oil blew into the coke can, so the only place it could be coming from is the intake, through the air bridge to settle in the IC. Can a busted piston or ring force oil through the intake and TB then down into the IC? Any insights are appreciated!

The Bat Car

Sure can. Reversion will distribute oil throughout the intake manifold (the higher the RPM the deeper reversion can travel back through the intact tract...all the way to and out of the inlet it'self in extreme cases) and you may want to make sure you dont have a seal out of the head unit allowing oil to enter.

Watched a video in super slow mo of a IRL engine at 12k or so and the reversion cloud was hovering 6 inches or so above the injector stacks....never would have thought it possible.

Adis

Well I dont have a leakdown gauge, nor do I have a compressor to run it even if I did. So, I used a tire and fed the air directly to cylinder #7 (I know - very ghetto.) I couldn't tell if it was at TDC but i think I could tell when the piston was up and the exhaust valve was open, so I just turned the crank one turn and figured that was TDC on the compression stoke. At 35 PSI I could definitely feel air coming out of the valve cover oil fill tube. But I opened the PCV hose from the valley port and couldn't feel any air. No air/sounds out of the exhaust, TB, or coolant overfill tank. I only tested cylinder #7 on Bat Car's recommendation that if there is a busted piston or ring that's probably the one. So does this tell me anything other than that I need to do a real leak down test?