High RPM Oil Leak

1LEDude · 02-05-2022, 03:38 PM

Hi All,

I am having an issue with a high RPM oil leak under full throttle conditions and thought I would see if anyone else has encountered anything like this as I am running out of ideas. It seems it starts around 4-5000 RPM. Thus far, I have replaced the rear main seal, oil cooler seals and removed and re-sealed the oil pan. The leak seems to start about half way along the sump towards the rear of the car. I am also awaiting delivery of a new dipstick tube o-ring and oil filter adapter seal as well.

Also, The car is a 2018 2SS 1LE if that matters.

1LEDude · 02-05-2022, 06:06 PM

I will make sure to check it. I’ve dyed the oil and looking for into those results now with a uv light.
Thank you for the suggestion

s346k · 02-05-2022, 07:55 PM

any idea what the crankcase pressure is doing?

1LEDude · 02-05-2022, 09:39 PM

I am not sure, that’s a good question. Do you have any suggestions as to how to check? I do have hp tuners and maybe able to data-log oil pressure, I’ll check for that pid.

My uv test shows oil hitting the flywheel and being slung everywhere, the back of the oil filter (the side near the flywheel) has oil but none on the front, the starter is soaked as well. On the passenger side there appears to be only oil on the starter snout and the back side of the oil level sensor. I fear the rear main or rear main housing is the issue. It’s hard to tell whether the oil pan is puking or the rear side of the engine with the tranny attached to the engine.

Joey Soul · 02-08-2022, 11:56 AM

I had to do the front main seal on my 18 ss last year. These engines build alot of crankcase pressure and the front is a 'low drag' paper thin seal. Mine would blow oil at high rpm only but it was alot that would dump. Then it would be fine at idle. I put in the ls3 front seal. Noticably thicker

SomeGeoffGuy · 02-08-2022, 12:49 PM

Try putting a vented oil cap in and see if it still leaks out. They make them with little K&N style filters on them.

-Geoff

WhiteMale · 02-08-2022, 01:09 PM

Until you said you had had the pan off and resealed I only saw that only leak when I had really ragged it pretty hard and I found a few oil pan bolts that were loose, took a half turn and since then it's stopped.

1LEDude · 02-10-2022, 11:36 PM

Thought I would leave a quick update on this, the oil is most definitely coming out of the bell housing. I found dyed oil on the starter snout, on top of the bell housing behind the top vent, on the rearward face of the oil filter but not on the front near the oil cooler and all over what I can see of the flywheel. I’ll have the tranny back out tomorrow night/Saturday morning and hopefully find the culprit, I’ve preemptively ordered a new rear main seal and rear main housing.

02-05-2022, 03:38 PM	#1
1LEDude Drives: 2SS 1LE Join Date: Nov 2021 Location: Tennessee Posts: 13	High RPM Oil Leak Hi All, I am having an issue with a high RPM oil leak under full throttle conditions and thought I would see if anyone else has encountered anything like this as I am running out of ideas. It seems it starts around 4-5000 RPM. Thus far, I have replaced the rear main seal, oil cooler seals and removed and re-sealed the oil pan. The leak seems to start about half way along the sump towards the rear of the car. I am also awaiting delivery of a new dipstick tube o-ring and oil filter adapter seal as well. Also, The car is a 2018 2SS 1LE if that matters.

02-05-2022, 07:55 PM	#3
s346k Drives: like an old lady Join Date: Jun 2012 Location: indiana Posts: 2,396	any idea what the crankcase pressure is doing? __________________ 2016+ camaro: everyone’s first car

02-08-2022, 11:56 AM	#5
Joey Soul The Mechanic Drives: 1SS M Join Date: Dec 2017 Location: NJ Posts: 291	I had to do the front main seal on my 18 ss last year. These engines build alot of crankcase pressure and the front is a 'low drag' paper thin seal. Mine would blow oil at high rpm only but it was alot that would dump. Then it would be fine at idle. I put in the ls3 front seal. Noticably thicker __________________ BTR 225 w/CNC Heads\|JLT intake\|Speed Engineering 1"7/8 long tube and mid pipe\|LT2 manifold w/95mmTb\|Self tuned w/HPtuners\|Silvers 2Way coilovers\|Hotchkis front sway\|Advan AD08R\|BMR solid cradle bushings\|Recaro SR7\| Work ZR10 19"

02-08-2022, 12:49 PM	#6
SomeGeoffGuy Drives: 2023 2SS Convertible Join Date: May 2009 Location: Metro Detroit Posts: 1,062	Try putting a vented oil cap in and see if it still leaks out. They make them with little K&N style filters on them. -Geoff __________________ '12 2SS RS Convertible - Traded in. '16 2SS Convertible - White on white, mag-ride, NPP, nav. Sold! '23 2SS Convertible -Same as above except orange.

02-05-2022, 06:06 PM	#2
1LEDude Drives: 2SS 1LE Join Date: Nov 2021 Location: Tennessee Posts: 13	I will make sure to check it. I’ve dyed the oil and looking for into those results now with a uv light. Thank you for the suggestion

02-05-2022, 09:39 PM	#4
1LEDude Drives: 2SS 1LE Join Date: Nov 2021 Location: Tennessee Posts: 13	I am not sure, that’s a good question. Do you have any suggestions as to how to check? I do have hp tuners and maybe able to data-log oil pressure, I’ll check for that pid. My uv test shows oil hitting the flywheel and being slung everywhere, the back of the oil filter (the side near the flywheel) has oil but none on the front, the starter is soaked as well. On the passenger side there appears to be only oil on the starter snout and the back side of the oil level sensor. I fear the rear main or rear main housing is the issue. It’s hard to tell whether the oil pan is puking or the rear side of the engine with the tranny attached to the engine.

02-08-2022, 01:09 PM	#7
WhiteMale Drives: 23 ZL1 A10 Rapid Blue Join Date: Aug 2020 Location: MO Posts: 1,992	Until you said you had had the pan off and resealed I only saw that only leak when I had really ragged it pretty hard and I found a few oil pan bolts that were loose, took a half turn and since then it's stopped.

02-10-2022, 11:36 PM	#8
1LEDude Drives: 2SS 1LE Join Date: Nov 2021 Location: Tennessee Posts: 13	Thought I would leave a quick update on this, the oil is most definitely coming out of the bell housing. I found dyed oil on the starter snout, on top of the bell housing behind the top vent, on the rearward face of the oil filter but not on the front near the oil cooler and all over what I can see of the flywheel. I’ll have the tranny back out tomorrow night/Saturday morning and hopefully find the culprit, I’ve preemptively ordered a new rear main seal and rear main housing.

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