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2G Oil Consumption

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WisconsinMonSTAR

Proven Member
129
29
Apr 20, 2014
Kenosha, Wisconsin
Hello all! I am somewhat stumped as to my engine's rate of oil consumption.

My car uses quite a bit of oil between changes. Over 2 quarts per 3k miles.

My compression test yielded 150 +/- 3 on various cylinders. Spark plugs have zero buildup; they look great after over 5k miles of rigorous driving (I race on the weekends and take frequent freeway trips). My exhaust does not spew any color of smoke. Not after long idles, not when I go WOT, not when I decel, or even when I decel and follow up by going WOT immediately after. I have also had my girlfriend start the car in the morning while I watch the tailpipe, and there is not a puff of smoke.

My oil pan is slightly grimy around the edges, but never does it leave any drips, or have any freshly wet looking oil. It just looks like grime stuck to mildly wet spots. Valve cover gaskets are all good and new.

Turbo has zero shaft play, pcv valve recently changed with a new oem unit, and crankcase breather (inline fuel filter on the vacuum line leading to intake tube) is pretty clean.

I cant figure out why my car is occasionally low on oil. Maybe I have a leak that only comes while driving? Or a leak that drips onto the downpipe and immediately burns off? Valve stem seals?

I plan on resealing my oil pan in the springtime, as well as doing a deep nook and cranny inspection for small leaks.

What else could be the issue here? The amount of oil I am having to add is far too much for me to suspect a large leak, considering I should be able to find it quite easily if that were the case. Also, with the amount of oil I am losing, I would expect to be seeing smoke clouds, especially when I am in WOT.

Any suggestions would be appreciated. Thanks!
 
Thanks for the input! I will clean and reseal my oil pan as soon as I get the opportunity. I will update this thread with results after doing so.

I suppose I will just deal with topping up for now.
 
Stupid question but are you sure you're checking your oil on level ground? Also, sometimes turbo's burn a small amount of oil over long drive times and it's not always visual. One of the perks of owning a turbo car.
 
Its not always perfectly level ground, but definitely not a ridiculous slope. Haha. I've considered that as well. Possibly a combination of a little burn from long drives as well as the slightly leaky oil pan. Oil is definitely going somewhere though!
 
So to find leaks:

1. Clean grime.
2. Drive car.
3. Inspect for newly leaked oil in the area you cleaned grime from.
4. If nothing found, buy UV dye and dye your oil.
5. Inspect engine bay with UV light at night time to look for glowing spots.

Driving with a grime spot and an oil leak is not a good way to find an oil leak. :)
 
Does your new PCV valve seal under boost? If it doesn't you will be blowing oil vapor from the rocker cover into the intake under boost and you won't see it on the plugs or in the exhaust, it just burns up except in the worst cases. I could only see it at night as a tint in trailing cars headlights.

Check the intercooler for oil, if the PCV is sealing any crankcase pressure will force the oil vapor down the pre-turbo vent. That oil will tend to collect in the IC.
 
Sorry for the late response, gentlemen! Something unexpected came up within my family. Have been all over the place. I cleaned the grime and drove around for a bit. I found that the grime did come back around where the oil pan mates to the block, as well as some fresh oil seeping from the timing side near the pan. I have yet to pull the timing cover due to weather conditions, but my next step will be to remove the cover and inspect.

So far, my to do list includes resealing my oil pan, and inspecting the timing component area.

Steve - I will perform another boost leak test sometine later this week, with the pcv unscrewed from the head. I will report back whether or not it is sealing.

I will also check my intercooler for oil once I have some better weather to do so.

Thanks for your input! I've got a lot of leads to work on now!
 
If your old pcv valve failed it can really cause the oil pan leak to get worse under boost. Most people think of the dipstick popping out as a sign there is too much pressure in the system, but an oil pan leak can definitely get worse under boost. Usually you would see parts behind the engine have a nice coating of grime.
 
I seem to have found at least one source of oil leaking. I found the the mounting stud for the oil filter that threads into the housing and sandwhiches the oil cooler had backed out a bit. This would explain the wetness around the bottom timing cover, since it only seems to be leaking while driving. For now, the stud has been retorqued, a new cooler o-ring is on its way, so I will be replacing it as soon as it arrives. Hopefully this will solve my issue, but I will post the results once I change it, and loctite the stud in place and drive a few hundred miles. Stay tuned!
 
Stupid question but are you sure you're checking your oil on level ground? Also, sometimes turbo's burn a small amount of oil over long drive times and it's not always visual. One of the perks of owning a turbo car.

I say this too. The ever so slight incline in my garage floor (so water doesnt accumulate) is enough to throw off my dipstick. Make sure you're always checking your oil at the same location.
 
Late update, but I've been extremely busy the past few weeks.

So I cleaned and resealed my oil pan while my turbo was out for a rebuild. Turbo return line gaskets were replaced, oil cooler o-ring was replaced, another brand new OEM pcv valve.

I no longer have any oil/grim on my pan or lower timing cover, but I'm still going through oil.

After the initial drive post turbo install, I checked for leaks. I can't find where it's coming from, but there is oil on the bottom of my intake manifold. It also appears to be fairly wet by my head gasket on the intake manifold side of the engine. Can a headgasket leak oil out of the engine without causing it to mix with the coolant?

My oil pan is bone dry, oil isn't trickling down from wherever this leak is coming from. I'm not sure what to do at this point other than replace the headgasket and see if it stops, if not, maybe I need a rebuild. :(
 
Yes oil could escape the Head gasket without being mixed into the coolant .... have you replaced you valve cover / rocker cover gasket. It could be seeping / leaking out of there and running around onto the bottom of the under side of your valve cover. Its a cheap fix over jumping straight to the head gasket.
 
If you pull the valve cover to replace that gasket, you should check to make sure the head studs are still torqued to the correct amount. If for some reason they have loosened or stretched at all it could cause the head to lift under boost.

I see that your 7 bolt is rebuilt, did you re-torque the head studs after a few heat cycles? Some say to do it after one full heat cycle but I like to give it an extra cycle or two.
 
I replaced my valve cover gasket last spring, but did not check the head studs when I did it. I will do that today
 
I just went out to check the head studs, they aren't studs. They're the stock 12 point bolts, and the service manual says to torque them down to 14.5 ft lbs and then give two 90 degree turns in sequence after that. I'm not sure how to go about or if I even should attempt to re torque stock head bolts. The valve cover gasket definitely was not leaking, I can assure you that.

Should I order some ARP head studs and attempt to swap them out 1 at a time and see if it solves my leaking issue? The head gasket I have appears to be MLS, it looks like a thick stack of bronze colored metal.
 
You're better off buying a good torque wrench and torque in sequence to 40 Ft-lbs, then to 60 Ft-lbs is what I believe should be the final TQ for 7 bolt engines. Look it up tho. Some people do 90-100Ft-lbs but that is with ARP hardware only.
 
I'm not an engine builder, but if your head bolts are in fact loose, you'll have bigger problems. I doubt that's the issue. My vote goes to your valve cover gasket. When mine was leaking, I got some residue underneath on the intake manifold runners. What can I say, gravity is a bi***.
 
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