Engine pukes oil when pushed hard.
Thread Starter
Racer
Joined: Aug 2010
Posts: 344
Likes: 0
From: Lebbrownsville Indiana
Engine pukes oil when pushed hard.
OK, so the first event I took the new car to the PCV valve was completely stuck, gunked up beyond belief. So the engine would puke oil out the oil cap and a little out the breather side. REplaced the PCV valve, new engine air filter and it now is fine, UNTIL it gets truly pushed, WOT, late braking and tighter turns on an auto-x course. Let it idle for a minute or two and it stops.
Am I looking at leaky rings? No, I have not run a compression/leak down test yet.
Am I looking at leaky rings? No, I have not run a compression/leak down test yet.
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
OK, so the first event I took the new car to the PCV valve was completely stuck, gunked up beyond belief. So the engine would puke oil out the oil cap and a little out the breather side. REplaced the PCV valve, new engine air filter and it now is fine, UNTIL it gets truly pushed, WOT, late braking and tighter turns on an auto-x course. Let it idle for a minute or two and it stops.
Am I looking at leaky rings? No, I have not run a compression/leak down test yet.
Am I looking at leaky rings? No, I have not run a compression/leak down test yet.
Leak down test at TDC would be your best bet
Thread Starter
Racer
Joined: Aug 2010
Posts: 344
Likes: 0
From: Lebbrownsville Indiana
No signs of sludge, just really dirty. PO didn't do much of anything to the car it appears. This oil still looks clean, but I'm going to change it again with another new filter to insure that it is. I run it hard, no point in skimping.
Oil pressure has never dropped below 40, even at idle, sitting in traffic with oil temps climbing towards 220. Car runs solid and it only pukes under extreme use. The car has 143k miles on it. I expect some things to need to be replaced/rebuilt/redone. It's not a show car by any means, but DAMN is this thing fun.
Oil pressure has never dropped below 40, even at idle, sitting in traffic with oil temps climbing towards 220. Car runs solid and it only pukes under extreme use. The car has 143k miles on it. I expect some things to need to be replaced/rebuilt/redone. It's not a show car by any means, but DAMN is this thing fun.
Last edited by Bobzilla; Sep 7, 2010 at 05:36 PM.
Thread Starter
Racer
Joined: Aug 2010
Posts: 344
Likes: 0
From: Lebbrownsville Indiana
OK, so it will ONLY push oil out of the oil cap/breather tube when pushed to redline. I pushed it in 2/3 gears this morning (run to almost redline) and it puked oil. Cleaned it up, drove it "normal" (think spirited with a steady cruise) and not a drop after 30 miles.
Wouldn't weak rings cause it to puke ALL the time? Makes no sense why it has to be pushed to it's limits to exhibit this behavior.
Oh, and for giggles a couple clean shots from yesterday:
Wouldn't weak rings cause it to puke ALL the time? Makes no sense why it has to be pushed to it's limits to exhibit this behavior.
Oh, and for giggles a couple clean shots from yesterday:
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Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
If so, it is possible that your '88 L98 w/ Alum heads may be
experiencing early stages of head gasket or possibly intake
gasket failure. Until you eliminate the possibility of coolant
getting into the oil, it would be best not to run the engine.
Any smell of glycol around the oil filler cap? Any recent issues
with momentary difficulty cranking? Anyone mention seeing
quantities of white vapour from the exhaust as you drive?
.
Thread Starter
Racer
Joined: Aug 2010
Posts: 344
Likes: 0
From: Lebbrownsville Indiana
No coolant in the oil, current oil still looks very good (about 900 miles on it), coolant is still pretty green with no signs of oil slicks. No smoke, even on startup (except the black smoke from extended cranking, likely bad FPR). Doesn't burn or use any fluids EXCEPT the oil that gets pushed out past the oil cap.
The oil that was in it hadn't been changed in a VERY long time. The pos filter I took off from a quickie lube had a 5-09 date on it, meaning it likely hadn't been changed since May of '09. I bought it August 2010. It was still full when I changed it.... just DARK brown, borderline "diesel black".
Believe it or not, this isn't my first go around with SBC's of this vintage, and I know my way around the engine bay fairly well. I'm just trying to eliminate all the extraneous stuff before I get too deep.
The oil that was in it hadn't been changed in a VERY long time. The pos filter I took off from a quickie lube had a 5-09 date on it, meaning it likely hadn't been changed since May of '09. I bought it August 2010. It was still full when I changed it.... just DARK brown, borderline "diesel black".
Believe it or not, this isn't my first go around with SBC's of this vintage, and I know my way around the engine bay fairly well. I'm just trying to eliminate all the extraneous stuff before I get too deep.
Thread Starter
Racer
Joined: Aug 2010
Posts: 344
Likes: 0
From: Lebbrownsville Indiana
I was also wondering if the intake breather or pcv port may not also be a bit clogged considering the condition of the pcv valve and the oil. Clogged enough that "normal" driving it doesn't build pressure, but under high loads and extended upper rpm use it builds pressure because it can't evacuate the pressure fast enough.....
Just a thought. I'll find out one way or another.
Just a thought. I'll find out one way or another.
Thread Starter
Racer
Joined: Aug 2010
Posts: 344
Likes: 0
From: Lebbrownsville Indiana
HEI. I haven't noticed any oil at the rear of the engine, all seems to come from the passenger valve cover on top. I noticed the cap doesn't seem to fit well though. Imight try another cap and a new (read: not dried out) breather grommet.
Racer
Joined: Jul 2010
Posts: 308
Likes: 2
From: Kansas City MO
Since you replaced the PCV valve and are going to replace the oil cap I'd replace the grommets holding it in and the hoses leading to the intake - if one collapses then it's as useless as having the old plugged up PCV in place.
Once you do that then I'd flush the engine (use a commercial motor flush or diesel/ATF to clean the sluge out) and then run a can of cleaner through the intake (spray carb cleaner through a vacuum port or use seafoam or any other top engine cleaner).
If those don't fix it then you're pressurizing the crankcase beyond what the PCV system can evacuate and it's time to look into a rebuild or a vacuum pump or additional crankcase venting (band-aid fixes)
Once you do that then I'd flush the engine (use a commercial motor flush or diesel/ATF to clean the sluge out) and then run a can of cleaner through the intake (spray carb cleaner through a vacuum port or use seafoam or any other top engine cleaner).
If those don't fix it then you're pressurizing the crankcase beyond what the PCV system can evacuate and it's time to look into a rebuild or a vacuum pump or additional crankcase venting (band-aid fixes)
Racer
Joined: Jul 2010
Posts: 308
Likes: 2
From: Kansas City MO
