Burning oil like a navy destroyer
08-19-2009, 11:46 PM
#1
Rainman
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Burning oil like a navy destroyer
Over the past few weeks I really seem to be going through alot of oil. I changed the oil and filter in mid September and put 6.5 qts in the pan (had a case of 12, 6 ended up in the trash and the 7th was put in the back of the car, with 5 left in the case) and since then I have put in probably 3 qts. I did make a long trip recently, driving from San Diego to San Jose and back (~900 miles) and while I was up there probably another 500 miles of cruising around the Bay Area. Almost all the miles driven were on the highway. I drive my car hard normally but on the highway the vast majority of the time was around 3000rpm in 5th on light throttle.
What would cause my car to burn so much oil? There are no visible oil leaks. I know the Porsche spec is 1 qt every 1000km (620 miles) but I am still well above that. My engine was fully rebuilt in 2006, all new bearings, rings, gaskets, every seal imagineable.
In searching I saw some stuff about bad AOS seals, could these be causing an excess amount of oil to be put into my intake and burned?
What would cause my car to burn so much oil? There are no visible oil leaks. I know the Porsche spec is 1 qt every 1000km (620 miles) but I am still well above that. My engine was fully rebuilt in 2006, all new bearings, rings, gaskets, every seal imagineable.
In searching I saw some stuff about bad AOS seals, could these be causing an excess amount of oil to be put into my intake and burned?
08-19-2009, 11:52 PM
#2
Nordschleife Master
Over the past few weeks I really seem to be going through alot of oil. I changed the oil and filter in mid September and put 6.5 qts in the pan (had a case of 12, 6 ended up in the trash and the 7th was put in the back of the car, with 5 left in the case) and since then I have put in probably 3 qts. I did make a long trip recently, driving from San Diego to San Jose and back (~900 miles) and while I was up there probably another 500 miles of cruising around the Bay Area. Almost all the miles driven were on the highway. I drive my car hard normally but on the highway the vast majority of the time was around 3000rpm in 5th on light throttle.
What would cause my car to burn so much oil? There are no visible oil leaks. I know the Porsche spec is 1 qt every 1000km (620 miles) but I am still well above that. My engine was fully rebuilt in 2006, all new bearings, rings, gaskets, every seal imagineable.
In searching I saw some stuff about bad AOS seals, could these be causing an excess amount of oil to be put into my intake and burned?
What would cause my car to burn so much oil? There are no visible oil leaks. I know the Porsche spec is 1 qt every 1000km (620 miles) but I am still well above that. My engine was fully rebuilt in 2006, all new bearings, rings, gaskets, every seal imagineable.
In searching I saw some stuff about bad AOS seals, could these be causing an excess amount of oil to be put into my intake and burned?
pull the plugs and check them....
IF no oil inside the j boot, but plugs show signs of oil, you either need a ring job, or valve stem seals....
When your lower end was rebuilt what did you have done to the head?
08-20-2009, 12:00 AM
#3
Rainman
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entire head disassembled, cleaned, machined, rebuilt with new valve seals. there was a little bit of oil in my j boost last time i checked.
tomorrow when its light ill check the plugs and j boot.
tomorrow when its light ill check the plugs and j boot.
08-20-2009, 12:05 AM
#4
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the manual states up to 1.5l/1000km or 1qt/400 miles...
sounds hign, but 3 qts/1200 miles would be within spec...
my concern would be if it changed drastically...say from 1qt/1000 to 1qt/500 in a couple tanks of gas...
sounds hign, but 3 qts/1200 miles would be within spec...
my concern would be if it changed drastically...say from 1qt/1000 to 1qt/500 in a couple tanks of gas...
08-20-2009, 12:14 AM
#5
Nordschleife Master
my 200K mile 951 with a bad turbo and a leaking oil pan doesn't even use close to those numbers... MAYBE 2 qts in 3000 miles or so... half of which is ending up in my intercooler...
08-20-2009, 12:22 AM
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just quoting the manual...
08-20-2009, 12:28 AM
#7
Nordschleife Master
I'm going to agree with John.
I know when I first got my car, it used a bit of oil (not nearly as much as yours). I pulled the J-boot off and it was full of oil. I swapped out the AOS seals, and now I have no oil in the intake and I barely use 1qt in 5,000 miles.
If its not that, I would say you have either a broken or a seized ring.... or valve stem seals.
I remember you last post about this, and you already said there was no milkshake in the coolant.... so those 3 things are about the only options.
I know when I first got my car, it used a bit of oil (not nearly as much as yours). I pulled the J-boot off and it was full of oil. I swapped out the AOS seals, and now I have no oil in the intake and I barely use 1qt in 5,000 miles.
If its not that, I would say you have either a broken or a seized ring.... or valve stem seals.
I remember you last post about this, and you already said there was no milkshake in the coolant.... so those 3 things are about the only options.
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08-20-2009, 12:45 AM
#9
Nordschleife Master
08-20-2009, 12:50 AM
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BMW for the e46 M3 quotes 1 qt/ 500 mi iirc...mine used <0.2 qt in ~6k mile changes...
it's probably a CYA figure...
08-20-2009, 03:06 AM
#11
Rainman
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i doubt it would be valve seals as those are from 2006. no milkshake in oil or coolant whatsoever. no visible leaks.
however the AOS seals would be from 2006 as well...maybe they just have a short life.
however even if its burning that much oil in that short a time, there is no smoke coming out my exhaust, no funny smells, nothing. exhaust smells like my mazda that got a full head rebuild and new head gaskets and just put back together yesterday.
however the AOS seals would be from 2006 as well...maybe they just have a short life.
however even if its burning that much oil in that short a time, there is no smoke coming out my exhaust, no funny smells, nothing. exhaust smells like my mazda that got a full head rebuild and new head gaskets and just put back together yesterday.
08-20-2009, 04:21 AM
#12
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What kind of oil are you using? These cars tend to 'drink' synthetic oil more easily than mineral.
If you're running full synthetic, I suggest you switch back to a good dino oil in 20W-50 weight and see how that goes.
If you're running full synthetic, I suggest you switch back to a good dino oil in 20W-50 weight and see how that goes.
08-20-2009, 04:23 AM
#13
Nordschleife Master
Yeah, I don't see how an engine that new would leak/burn that much oil either..... but it has to be going somewhere.
Pull the intake boot first and check it out.
^^^^ Sorry, but I doubt the actual oil has anything to do with it. Not with as much as is going away, in such a short amount of time.
Pull the intake boot first and check it out.
^^^^ Sorry, but I doubt the actual oil has anything to do with it. Not with as much as is going away, in such a short amount of time.
08-20-2009, 05:23 AM
#15
Nordschleife Master
Air Oil Seperator..... its the plastic tank thing with the yellow cap that you dump oil into when you change the oil.
Its Porsche's version of a PCV valve. It has 2 silicone o-rings on it that go bad.
Its Porsche's version of a PCV valve. It has 2 silicone o-rings on it that go bad.