Why would Auto Oil turn into yellow sludge?

kookbreaker · 9th January 2006, 09:14 AM

OK, odd science problem here. My car has ahd an oil change lately, and the past couple of times the oil changer has pointed out that the cap had a yellow sludge on it. From what I don't know. I had them do an engine purge. Fast foward a little bit, I was checking my oil today and found that the cap, the pipe leading to the oil resevoir and the dipstick all hav the same yellow sludge. I am using synthetic oil and my car is a 2000 VW Golf if that matters at all.

HighRiser · 9th January 2006, 09:27 AM

Water in the crankcase. If you're lucky it is condensation. If you're less lucky it could be a torn head gasket. If you're luckless it could be a cracked block or head. Good luck...

thrombus29 · 9th January 2006, 09:33 AM

It's moisture in the oil making a frothy emulsion, could be condensation or it could be a leaky head gasket.

Are you losing antifreeze?

thrombus29 · 9th January 2006, 09:34 AM

I gotta learn to type faster.

kookbreaker · 9th January 2006, 10:19 AM

I don't think I am losing antifreeze. The pan was leaking before and had to be replaced, and I am not certain they did the job right (my last oil change required a top-off return trip, and it is synthetic oil). Could water be getting in from there?

Capsid · 9th January 2006, 10:27 AM

Sludge is an inevitbality of synthetic oils. This article is quite helpful and suggests changing the oil at appropriate intervals.

HeyLeroy · 9th January 2006, 10:49 AM

If you're in a cold climate, when you shut off your engine water condenses inside the cylinders. This is the foundation of that sludge (I worked at a quick-lube place many moons ago). I'm guessing your commutes are fairly short? Over a longer drive, this moisture should evaporate and be released by the crankcase ventilation system. If you don't have a cracked head (no offense

) or a torn head gasket, try replacing your PCV valve, maybe $3, and take a good, long drive to get the engine up to temp for a while. IMO, they bent you over doing that engine 'purge'.

(ETA) Using synthetic is a good idea, but you'll see the same sludge-y buildup using conventional oil, take my word for it.

jj · 9th January 2006, 11:48 AM

Yellow oil (synthetic or otherwise) is water as the first poster said.

If you drive it a while on the freeway (until the oil temperature gets up as well as the water temperature, at least an hour) and it's still yellow, you have a serious problem and need to find out where the water is coming from.

If you see ANY hint of oil pressure or operation issues, STOP. STOP STOP STOP.

It is possible, but only just, to create this problem with condensation with consistant short-drive usage that never gets things warmed up. That's bad for your car in lots of ways, btw.

kookbreaker · 9th January 2006, 12:38 PM

My commutes are very short. 12 miles to work and 12 miles back, so that fits. I'll have to resist their selling of the purges, since they seem to do more harm than good. I have had no signs of oil pressure problems, though.

I can't really do too much about it. My commutes are short. Back in the day, when I was driving the museum cars I would drive them 2 hours there and 2 hours back all the time. But that is not what I do anymore.

luchog · 9th January 2006, 01:22 PM

Once, when working on an old Ford Pinto I used to own, I managed to crack the head gasket between a coolant channel and a cylinder. Within about 3 miles, the contents of the oil pan had turned into something almost exactly the colour and consistency of chocolate mousse.

Cleaning that out was one of my least favorite auto repair jobs, ever.

casebro · 9th January 2006, 02:58 PM

Old mechanic that I am, I'd say to get your crankcase ventilation system checked out. 12 miles ought to be far enough to get things up to temp, but without good flow through ventilation the vapors won't get pulled out. Stuff like PCV valve, filter, plugged hoses.....

jj · 9th January 2006, 04:40 PM

Originally Posted by casebro

Old mechanic that I am, I'd say to get your crankcase ventilation system checked out. 12 miles ought to be far enough to get things up to temp, but without good flow through ventilation the vapors won't get pulled out. Stuff like PCV valve, filter, plugged hoses.....

Agreed 100% with casebro.

12 miles each way might collect a bit of moisture, but not very much, and certainly not enough to be strikingly obvious.

_Q_ · 9th January 2006, 07:19 PM

Originally Posted by kookbreaker

OK, odd science problem here. My car has ahd an oil change lately, and the past couple of times the oil changer has pointed out that the cap had a yellow sludge on it. From what I don't know. I had them do an engine purge. Fast foward a little bit, I was checking my oil today and found that the cap, the pipe leading to the oil resevoir and the dipstick all hav the same yellow sludge. I am using synthetic oil and my car is a 2000 VW Golf if that matters at all.

I think you've received some pretty good advice here from others.

I'll add to that the recommendation that you do some digging to see if any applicable make/model/year-specific information might be available. There are some fairly supportive on-line communities based on enthusiasm for different sorts of cars, and I imagine that this would apply to VW as well. It's often the case that certain specific issues with particular cars, engines, transmissions, etc. are very well known in such communities.

Search before posting a question. If you can't find anything, it's usually a good policy to preface the question with something like, "OK, I've searched the archives for information on (yellow sludge, goo, whatever), and I couldn't turn up anything..."

I did a little searching at http://forums.vwvortex.com, and saw some posts describing observations very similar to yours. In some cases, suggestions were offered regarding specific things for which to check - possibly cracked dipstick tubes, leaky seals on oil filler caps, etc.

HeyLeroy · 9th January 2006, 07:53 PM

In my experience, VeeDubs and Hondas seemed to show this more than other makes.

KingMerv00 · 10th January 2006, 07:05 AM

Water + oil + mix = yellowish emulsion

I know this was said a bamillion times already, but I'd just thought I'd say my peace. My old job involved testing oils in different ways and the emulsion test was one.

Tests have been performed in a lab. Skeptical feelings may be put to rest.

LTC8K6 · 10th January 2006, 07:44 AM

I have just a five mile trip to work, so I make an effort to drive my car for longer periods once in a while to avoid condensation/sludge trouble. Once in a while I just take a really long route to get everything up to temperature for a while.

12 miles should really be enough though, I would think.

Maybe you could start taking a bit longer trip each weekend?

jj · 10th January 2006, 10:37 AM

Originally Posted by KingMerv00

Water + oil + mix = yellowish emulsion

I know this was said a bamillion times already, but I'd just thought I'd say my peace. My old job involved testing oils in different ways and the emulsion test was one.

Tests have been performed in a lab. Skeptical feelings may be put to rest.

Oh, indeed, I'm quite confident of what it means, myself, having seen the experiment made by at least a half-dozen head gaskets, a couple of cracked heads, a busted GM intake manifold or three

9th January 2006, 09:14 AM	#1
kookbreaker Evil Fokker Join Date: Aug 2001 Posts: 9,174	Why would Auto Oil turn into yellow sludge? OK, odd science problem here. My car has ahd an oil change lately, and the past couple of times the oil changer has pointed out that the cap had a yellow sludge on it. From what I don't know. I had them do an engine purge. Fast foward a little bit, I was checking my oil today and found that the cap, the pipe leading to the oil resevoir and the dipstick all hav the same yellow sludge. I am using synthetic oil and my car is a 2000 VW Golf if that matters at all.
kookbreaker Evil Fokker Join Date: Aug 2001 Posts: 9,174	__________________ Thanks for helping me win Best Children's Gifts and Best Toys in Philly Voter in 2011 & 2012! Spectrum Scientifics - My store - Google it people!

9th January 2006, 09:33 AM	#3
thrombus29 Flame War Master and JREF kid Join Date: Aug 2001 Posts: 1,924	It's moisture in the oil making a frothy emulsion, could be condensation or it could be a leaky head gasket. Are you losing antifreeze?
	__________________ Now I am not going to justify what may appear to be a failure in carrying out this prediction but rest in the fact that there will be success. -St. Paul Bethke Targzissians are obviously reptilian

9th January 2006, 09:34 AM	#4
thrombus29 Flame War Master and JREF kid Join Date: Aug 2001 Posts: 1,924	I gotta learn to type faster.
	__________________ Now I am not going to justify what may appear to be a failure in carrying out this prediction but rest in the fact that there will be success. -St. Paul Bethke Targzissians are obviously reptilian

9th January 2006, 10:19 AM	#5
kookbreaker Evil Fokker Join Date: Aug 2001 Posts: 9,174	I don't think I am losing antifreeze. The pan was leaking before and had to be replaced, and I am not certain they did the job right (my last oil change required a top-off return trip, and it is synthetic oil). Could water be getting in from there?
kookbreaker Evil Fokker Join Date: Aug 2001 Posts: 9,174	__________________ Thanks for helping me win Best Children's Gifts and Best Toys in Philly Voter in 2011 & 2012! Spectrum Scientifics - My store - Google it people!

9th January 2006, 10:27 AM	#6
Capsid Graduate Poster Join Date: Apr 2004 Posts: 1,506	Sludge is an inevitbality of synthetic oils. This article is quite helpful and suggests changing the oil at appropriate intervals.
Capsid Graduate Poster Join Date: Apr 2004 Posts: 1,506

9th January 2006, 09:27 AM	#2
HighRiser Critical Thinker Join Date: Nov 2005 Location: High above Indianapolis Posts: 341	Water in the crankcase. If you're lucky it is condensation. If you're less lucky it could be a torn head gasket. If you're luckless it could be a cracked block or head. Good luck...

9th January 2006, 10:49 AM	#7
HeyLeroy Vegan Cannibal Join Date: Oct 2005 Location: Going off the rails on the Crazy Train. Posts: 5,565	If you're in a cold climate, when you shut off your engine water condenses inside the cylinders. This is the foundation of that sludge (I worked at a quick-lube place many moons ago). I'm guessing your commutes are fairly short? Over a longer drive, this moisture should evaporate and be released by the crankcase ventilation system. If you don't have a cracked head (no offense ) or a torn head gasket, try replacing your PCV valve, maybe $3, and take a good, long drive to get the engine up to temp for a while. IMO, they bent you over doing that engine 'purge'. (ETA) Using synthetic is a good idea, but you'll see the same sludge-y buildup using conventional oil, take my word for it.
	__________________ Cows are in large numbers, and do not serve any other purpose, other than to eat grass, and moo -- makaya325 I ♥ my kids. I ♠ my dog. I ♣ my baby Harp Seal.

9th January 2006, 11:48 AM	#8
jj grumpy old skeptic Join Date: Oct 2001 Location: Deep in the rain Posts: 18,503	Yellow oil (synthetic or otherwise) is water as the first poster said. If you drive it a while on the freeway (until the oil temperature gets up as well as the water temperature, at least an hour) and it's still yellow, you have a serious problem and need to find out where the water is coming from. If you see ANY hint of oil pressure or operation issues, STOP. STOP STOP STOP. It is possible, but only just, to create this problem with condensation with consistant short-drive usage that never gets things warmed up. That's bad for your car in lots of ways, btw.
	__________________ The Power to Quit

9th January 2006, 12:38 PM	#9
kookbreaker Evil Fokker Join Date: Aug 2001 Posts: 9,174	My commutes are very short. 12 miles to work and 12 miles back, so that fits. I'll have to resist their selling of the purges, since they seem to do more harm than good. I have had no signs of oil pressure problems, though. I can't really do too much about it. My commutes are short. Back in the day, when I was driving the museum cars I would drive them 2 hours there and 2 hours back all the time. But that is not what I do anymore.
kookbreaker Evil Fokker Join Date: Aug 2001 Posts: 9,174	__________________ Thanks for helping me win Best Children's Gifts and Best Toys in Philly Voter in 2011 & 2012! Spectrum Scientifics - My store - Google it people!

9th January 2006, 01:22 PM	#10
luchog Neo-Post-Retro-Revivalist Join Date: Aug 2005 Location: The Emerald City Posts: 7,957	Once, when working on an old Ford Pinto I used to own, I managed to crack the head gasket between a coolant channel and a cylinder. Within about 3 miles, the contents of the oil pan had turned into something almost exactly the colour and consistency of chocolate mousse. Cleaning that out was one of my least favorite auto repair jobs, ever.
	__________________ "All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others." -- Douglas Adams "The absence of evidence might indeed not be evidence of absence, but it's a pretty good start." -- PhantomWolf "Let's see the buggers figure that one out." - John Lennon

9th January 2006, 02:58 PM	#11
casebro Philosopher Join Date: Jun 2005 Posts: 6,792	Old mechanic that I am, I'd say to get your crankcase ventilation system checked out. 12 miles ought to be far enough to get things up to temp, but without good flow through ventilation the vapors won't get pulled out. Stuff like PCV valve, filter, plugged hoses.....
casebro Philosopher Join Date: Jun 2005 Posts: 6,792	__________________ Please pardon me for having ideas, not facts. Some have called me cynical, but I don't believe them. It's not how many breaths you take. It's how many times you have been breathless that counts.

9th January 2006, 04:40 PM	#12
jj grumpy old skeptic Join Date: Oct 2001 Location: Deep in the rain Posts: 18,503	Originally Posted by casebro Old mechanic that I am, I'd say to get your crankcase ventilation system checked out. 12 miles ought to be far enough to get things up to temp, but without good flow through ventilation the vapors won't get pulled out. Stuff like PCV valve, filter, plugged hoses..... Agreed 100% with casebro. 12 miles each way might collect a bit of moisture, but not very much, and certainly not enough to be strikingly obvious.
	__________________ The Power to Quit

9th January 2006, 07:19 PM	#13
_Q_ Critical Thinker Join Date: Dec 2002 Location: Florida Big Bend region Posts: 276	Originally Posted by kookbreaker OK, odd science problem here. My car has ahd an oil change lately, and the past couple of times the oil changer has pointed out that the cap had a yellow sludge on it. From what I don't know. I had them do an engine purge. Fast foward a little bit, I was checking my oil today and found that the cap, the pipe leading to the oil resevoir and the dipstick all hav the same yellow sludge. I am using synthetic oil and my car is a 2000 VW Golf if that matters at all. I think you've received some pretty good advice here from others. I'll add to that the recommendation that you do some digging to see if any applicable make/model/year-specific information might be available. There are some fairly supportive on-line communities based on enthusiasm for different sorts of cars, and I imagine that this would apply to VW as well. It's often the case that certain specific issues with particular cars, engines, transmissions, etc. are very well known in such communities. Search before posting a question. If you can't find anything, it's usually a good policy to preface the question with something like, "OK, I've searched the archives for information on (yellow sludge, goo, whatever), and I couldn't turn up anything..." I did a little searching at http://forums.vwvortex.com, and saw some posts describing observations very similar to yours. In some cases, suggestions were offered regarding specific things for which to check - possibly cracked dipstick tubes, leaky seals on oil filler caps, etc.

9th January 2006, 07:53 PM	#14
HeyLeroy Vegan Cannibal Join Date: Oct 2005 Location: Going off the rails on the Crazy Train. Posts: 5,565	In my experience, VeeDubs and Hondas seemed to show this more than other makes.
	__________________ Cows are in large numbers, and do not serve any other purpose, other than to eat grass, and moo -- makaya325 I ♥ my kids. I ♠ my dog. I ♣ my baby Harp Seal.

10th January 2006, 07:05 AM	#15
KingMerv00 Penultimate Amazing Join Date: Nov 2004 Location: Philadelphia, PA...USA Posts: 14,482	Water + oil + mix = yellowish emulsion I know this was said a bamillion times already, but I'd just thought I'd say my peace. My old job involved testing oils in different ways and the emulsion test was one. Tests have been performed in a lab. Skeptical feelings may be put to rest.
	__________________ If man came from dust, why is there still dust?

10th January 2006, 07:44 AM	#16
LTC8K6 Penultimate Amazing Join Date: Nov 2002 Location: Directly under a deadly chemtrail Posts: 12,629	I have just a five mile trip to work, so I make an effort to drive my car for longer periods once in a while to avoid condensation/sludge trouble. Once in a while I just take a really long route to get everything up to temperature for a while. 12 miles should really be enough though, I would think. Maybe you could start taking a bit longer trip each weekend?

10th January 2006, 10:37 AM	#17
jj grumpy old skeptic Join Date: Oct 2001 Location: Deep in the rain Posts: 18,503	Originally Posted by KingMerv00 Water + oil + mix = yellowish emulsion I know this was said a bamillion times already, but I'd just thought I'd say my peace. My old job involved testing oils in different ways and the emulsion test was one. Tests have been performed in a lab. Skeptical feelings may be put to rest. Oh, indeed, I'm quite confident of what it means, myself, having seen the experiment made by at least a half-dozen head gaskets, a couple of cracked heads, a busted GM intake manifold or three
	__________________ The Power to Quit