Is this normal?
Thread Starter
Melting Slicks
Joined: Mar 2007
Posts: 2,216
Likes: 5
From: Longmont Colorado
Is this normal?
So i was changing my oil and popped off the oil cap and just happened to notice that a little layer of dark yellow sludge looking matter was on the top of the oil cap. Is this cause for concern? When i drive i always look to see if its still there and sometimes it is sometimes its perfectly clean. The car is perfectly fine no problems at all its a 99 with 46000 miles lots of mods. can anyone help?
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
Some people have seen a brownish buildup there. I wouldn't worry about it, but if you want piece of mind, do an oil analysis. Blackstone Labs is where I send my oil, cost is $20-25.
Your oil on the dipstick looks okay ? No milkly white color (water in oil) right?
Your oil on the dipstick looks okay ? No milkly white color (water in oil) right?
Le Mans Master
Joined: Oct 2007
Posts: 6,866
Likes: 768
From: Kelso Washington
St. Jude Donor '09, '13, '15
Sounds like you've got a bit of moisture in your crankcase. If your car has sat for awhile it could be natural condensation. Since you are changing the oil, just keep an eye on the inside of that cap for awhile. Hopefully it won't re-appear. Sometimes it's an early sign of head gasket failure, hopefully that is not the case.
Can some of the 'Vetterans" here think of other places in an LS1 where coolant can get into the crankcase?
Can some of the 'Vetterans" here think of other places in an LS1 where coolant can get into the crankcase?
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Burning Brakes
Joined: Dec 2003
Posts: 1,066
Likes: 9
From: Eddy Texas
I get the same thing from time to time on both my vehicles. I think it's just from a lot of short trips, where the engine does'nt have a chance to build up enough heat to get rid of any condensation in the crankcase. If the stick looks good and the "residue" isn't milky and fresh, I'd say your okay. As stated before, an oil analysis will confirm either way. Good luck.
Instructor
Joined: Aug 2007
Posts: 158
Likes: 0
From: DFW Big State Of Texas
Sounds like you've got a bit of moisture in your crankcase. If your car has sat for awhile it could be natural condensation. Since you are changing the oil, just keep an eye on the inside of that cap for awhile. Hopefully it won't re-appear. Sometimes it's an early sign of head gasket failure, hopefully that is not the case.
Can some of the 'Vetterans" here think of other places in an LS1 where coolant can get into the crankcase?
Can some of the 'Vetterans" here think of other places in an LS1 where coolant can get into the crankcase?
Condensation Just keep a eye on it.Most common fail point for coolant in engine is head gaskets.
I have seen some other reasons but it was a abused motor.
Race Director
Joined: Jun 2005
Posts: 17,640
Likes: 1
From: Lenoir City TN
St. Jude Donor '08-'09-'10-'11
Keep an eye on it, I had that on a Ford and it was due to leaking intake gaskets letting coolant into the oil then evaporating onto the cap, since I fixed the gaskets it does not happen anymore.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I'll comment on this too. My high mileage '99, when I had the heads off a couple of years ago to replace the lifters, I found this yellow scum like stuff all over inside. It wasn't a lot, but looked more like a film on everything. I've only used Mobil1 and never anything else. It was an oily substance. I wrote to Mobil about it, but they said they had no idea unless I got a formal analysis done on it.
Thread Starter
Melting Slicks
Joined: Mar 2007
Posts: 2,216
Likes: 5
From: Longmont Colorado
I'll comment on this too. My high mileage '99, when I had the heads off a couple of years ago to replace the lifters, I found this yellow scum like stuff all over inside. It wasn't a lot, but looked more like a film on everything. I've only used Mobil1 and never anything else. It was an oily substance. I wrote to Mobil about it, but they said they had no idea unless I got a formal analysis done on it.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Sounds like you've got a bit of moisture in your crankcase. If your car has sat for awhile it could be natural condensation. Since you are changing the oil, just keep an eye on the inside of that cap for awhile. Hopefully it won't re-appear. Sometimes it's an early sign of head gasket failure, hopefully that is not the case.
Can some of the 'Vetterans" here think of other places in an LS1 where coolant can get into the crankcase?
Can some of the 'Vetterans" here think of other places in an LS1 where coolant can get into the crankcase?
it could be natural condensation if its a while since the oil was changed or the car has been idle for a whileIf it is the early signs of a head gasket problem, best have it checked out. You'd have white smoke in the exhaust. A compression test will flag up any issues. Water and pistons dont mix well.
I just had exactly the same problem with my son's Camaro but we caught it before any damage was done. A strip down was expensive but saved the engine blowing. I'm sure the engine gurus will chime up but I'm just naturally cautious on engine problems.
Last edited by DeeGee; Dec 17, 2007 at 01:54 AM.
Race Director
Joined: Jul 2004
Posts: 16,794
Likes: 62
From: Lake Havasu City, AZ
it reads like condensation from short trips.
That is exactly why it is best not to start your car over the winter...
As noted by DeeGee it could also be early warning signs of a head gasket problem. BUT with only 49K that probability is rather low.
You might want to have it checked out sometime soon.
That is exactly why it is best not to start your car over the winter...
As noted by DeeGee it could also be early warning signs of a head gasket problem. BUT with only 49K that probability is rather low.
You might want to have it checked out sometime soon.
Instructor
Joined: Oct 2007
Posts: 194
Likes: 0
From: Mesa Arizona
I would say if your oil looks good & its just on the cap, its probably just moisture from condensation. With colder weather or high humidity. I used to see that when I lived in Alaska, parked in a warn garage and cold outside make for condensation in oil & gas. Just a thought.
