Is this possible? My LS1 has good compression- 205-210 in all cylinders. Yet I burn a quart of oil every 300 to 400 miles. I was thinking it could be the valve seals or the valve guides, but I have been told they would not lead to oil consumption of this magnitude. I have tried Auto-Rx, no change. I have switched to a heavier weight oil, still no change in oil consumption. Any ideas or suggestions?
Can rings be bad if compression is good?
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I don't think so, Ken. I have a brand-new PCV valve, LS6 PCV system conversion, an AMW catchcan inline in the PCV system, and a Metco valve cover breather. The catchcan catches a little bit of oil, but not near what I am losing.
I'd say rings are a possibility. Most engines have a separate oil control ring. If that was bad, but the compression ring was good, you might still get good compression, but have oil passing by the rings.
Have you removed the spark plugs? Oil consumption of that magnitude will certainly show on the plugs. It would be worthwhile to find out if the problem is on one or multiple cylinders.
Have you removed the spark plugs? Oil consumption of that magnitude will certainly show on the plugs. It would be worthwhile to find out if the problem is on one or multiple cylinders.
That is exactly the scenario I was imagining, Matt- compression rings are doing their job, but the oil control rings are not.
I have not checked the plugs, but they were replaced recently- new plugs and wires.
Even with new plugs, I am experiencing idle and drivability problems- stalling, surging at idle, hesitation, etc.
I have also gotten the dreaded flashing "Service Engine Soon" light a couple of times, which I was told indicates multiple random misfires. Oddly enough, when I tried to pull the codes with EFI Live, the PCM had not stored the DTC's in memory. My guess is the new plugs are in the process of being fouled out by all the oil in the combustion chambers.
I have not checked the plugs, but they were replaced recently- new plugs and wires.
Even with new plugs, I am experiencing idle and drivability problems- stalling, surging at idle, hesitation, etc.
I have also gotten the dreaded flashing "Service Engine Soon" light a couple of times, which I was told indicates multiple random misfires. Oddly enough, when I tried to pull the codes with EFI Live, the PCM had not stored the DTC's in memory. My guess is the new plugs are in the process of being fouled out by all the oil in the combustion chambers.
Try an Auto Rx treatment.
You sound like a perfect candidate.
You sound like a perfect candidate.
Weird! My 02 LS1 has never burned any oil from day 1 and still does not even with my mods. I did the LS6 PCV conversion when I swapped in my heads as I also have an LS6 block so it was really easy. How do your drive the car? Low speeds @ high rpms? It just does not make since that some burn oil like crazy and ones like mine burn none at all?
I'm already on my second Auto-Rx treatment. I've been through one Auto-Rx cleaning cycle, and one rinse cycle already- although, I have to admit- both times I changed out the oil earlier than I was supposed to. I hated to do it, but if you had seen this oil you would have changed it, too! Some of the nastiest, dirtiest oil I have ever seen. So obviously the Auto-Rx is doing something. I just cannot understand how my engine got so dirty- I have always used Mobil 1 or Redline oil, and have never even done extended OCI's (3000 mile change intervals, usually).
I would love to get Patman's input here, since he is a respected LS1 guru.
I would love to get Patman's input here, since he is a respected LS1 guru.
I would say valve stem seals. The oil control rings could possibly be a problem but I doubt it. No external leaks? Can you see a blue color to the exhaust under any driving conditions. I would think with that amount of oil burnig you would notice blue exhaust. Good luck.
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I know that, at least in the case of the Audi 2.8 12 valve engine, worn rings (compression and oil rings) do not necessarily manifest themselves in bad compression.
Thanks for the input, guys.
Ryan- you are one of the lucky ones- my stock LS1 started burning oil somewhere around 8-12K, and it just gradually got worse and worse. I had the rings replaced under warranty per the GM TSB for excessive oil consumption, but my engine continued to burn oil at the same rate, even with new rings!! I would say about a quart every 500-700 miles on the stock shortblock.
Then,with between 25K-30K miles on the stock shortblock, I replaced it with an ARE (Agostino Racing Engines) forged 346cid shortblock. This engine has always burned oil, too- just like the stock one. Only now, it's worse- it is burning over a quart every 300 miles now.
I would say my driving habits are fairly normal. The car is a 6 speed manual, and they do tend to have more of a problem than automatics. The only thing I do which may contribute to oil consumption is I do tend to downshift and use "engine braking" when slowing down or stopping. My father taught me to drive this way- easier on the brakes...but is it bad for the engine??
I don't think the problem is with the valve seals or valve guides- I have brand-new TEA (Total Engine Airflow) ported LS6 heads. I have heard of no issues with oil consumption with TEA heads.
Ryan- you are one of the lucky ones- my stock LS1 started burning oil somewhere around 8-12K, and it just gradually got worse and worse. I had the rings replaced under warranty per the GM TSB for excessive oil consumption, but my engine continued to burn oil at the same rate, even with new rings!! I would say about a quart every 500-700 miles on the stock shortblock.
Then,with between 25K-30K miles on the stock shortblock, I replaced it with an ARE (Agostino Racing Engines) forged 346cid shortblock. This engine has always burned oil, too- just like the stock one. Only now, it's worse- it is burning over a quart every 300 miles now.
I would say my driving habits are fairly normal. The car is a 6 speed manual, and they do tend to have more of a problem than automatics. The only thing I do which may contribute to oil consumption is I do tend to downshift and use "engine braking" when slowing down or stopping. My father taught me to drive this way- easier on the brakes...but is it bad for the engine??
I don't think the problem is with the valve seals or valve guides- I have brand-new TEA (Total Engine Airflow) ported LS6 heads. I have heard of no issues with oil consumption with TEA heads.
I don't know anything about your engine, but I've ran chevy big blocks. I did see and increase in oil consumption with the use of chrome bow-tie valve covers. Orginal chevy valve covers had something like a baffel that protected the pcv valve. The bow-tie valve covers offered no protection from spashing oil on the pcv valve. I've also have heard of poorly designed valve covers that had the pcv valve located above a push rod and oil spashed/shot right up to the valve. Just something to look at.
Personally, if the above doesn't fit your problem, I'd replace the valve stem seals. I've replaced them on my oil comsuming dodge truck and now have zero oil consumption on a 125,000+ engine.
Personally, if the above doesn't fit your problem, I'd replace the valve stem seals. I've replaced them on my oil comsuming dodge truck and now have zero oil consumption on a 125,000+ engine.
Thanks for the response, Bullet. You nailed one of the LS1 problems- the PCV system. However, I have converted over to the LS6 PCV system which actually relocates the PCV valve to draw from the valley cover (under the intake manifold, between the heads).
I was going to replace the valve stem seals, but many people have said bad valve seals could not cause this level of oil consumption.
Also, ARE has a pretty bad reputation in the LS1 community, which makes the shortblock look like a good candidate for being the problem.
I was going to replace the valve stem seals, but many people have said bad valve seals could not cause this level of oil consumption.
Also, ARE has a pretty bad reputation in the LS1 community, which makes the shortblock look like a good candidate for being the problem.
Bad intake valve stems/guides/seals certainly can lead to heavy oil consumption. High vacuum conditions, that is, idle and engine braking will tend to pull oil down the intake guides. Bad oil control rings will merely use more oil proportional to rpms. I notice a lot of complaints about oil consumption on late model US engines, such as the Ford V-10, Olds Aroura V-8 and GM 4.3 V-6.
Brake pads are cheap.... Engines are.. well ... you know. $$$
That is an awfull lot of oil you are burning. You said that after they changed the rings the oil consumption was not any better. Are you sure they actually did the work?
OK, now I reread everything. This is your second engine? If you count the re-ring job, this is your third engine?!?! All had the same symptom of burning a quart every 500miles?!?!
Get rid of the oil catch can.
With the ARX, are you using synthetic oil?
Have you done an oil analysis? Do you have coolant in the oil? How about fuel dilution?
This is correct, although the seals may be faily new, they would be a little on the high side of tolarances. This is cheap if you can do it yourself. I did mine buy pulling all plugs, putting rope down the plug hole and rotating the engine until it bined.
On a side note, was this short block assembled with chrome rings? If so, it may take that kind of milage to seat the rings.
On a side note, remove the pcv valve hose and plug it and let the engine breath into the air. if oil consumption decreases them you have a pcv problem.
I had an IROC Camaro back in the day...& after a heavy thrashing, it started acting up like yours. Fouling certain plugs, using lots of oil...turns out is was a cracked oil control ring.
Hope its not the case for your Chevy. Good luck bro.
Hope its not the case for your Chevy. Good luck bro.
I have not done an oil analysis yet. The oil gets really dark, really fast. I can tell you that much.
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