used car shopping: how to check oil consumption

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Is there even a way to detect oil burners on a short test drive short of removing spark plugs? I'm well aware that cars with working cat converters can burn 1qt in under 500 miles (or more) with no visible smoke.
 
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Plausibly you could feel it inside the tailpipe, but my saturn burner tailpipes are just normally sooty.
 
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Try to start it up cold. Catcons take at least 30 seconds to start working at all, so you could probably at least smell the characteristic smell of an oil burner even without visible smoke. Also, if it burns oil past the rings then more blow-by is going to be going the OTHER way. Open the oil fill cap with the engine running and after a long enough drive to get everything fully hot- if the PCV system can't keep up and visible vapor is coming OUT of the oil cap, run away.
 
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Originally Posted By: SumpChump
I check the PVC valve and area.
+1
 

Nick1994

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How we found out on my brother's 96' Lexus (unfortunately after) he bought it was while driving on the highway and I was following, I called him and told him to floor it. He did and out came a cloud. Runs great, just burns a quart every 500 miles
 
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In addition to a good check of the car 'in general', I like to check the maint documentation and a good chat with the seller. If it's a dealer, sometimes it's one they sold new and often have the file-if not I've had them call the previous owner for permission to have a chat. I'm not too sure of anything I'd try otherwise in any testing as I don't think of something to give you a quick answer for a long term problem other than compression/leakdown type testing that isn't usually very practical to do in this situation.
 
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Very hard to tell, and some people are washing their hands of oil burners on trade in. Seems like ever manufacture has a problem in select categories. With private sellers sometimes cars are not detailed, sooo usually you can see black soot on rear bumper near exhaust exit.
 

friendly_jacek

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Originally Posted By: 440Magnum
Try to start it up cold. Catcons take at least 30 seconds to start working at all, so you could probably at least smell the characteristic smell of an oil burner even without visible smoke.
Here is an idea: How about adding a smelly additive to oil before driving, so the smell would be obvious. Now, what additive would that be? But, how about bluffing the seller and asking permission to add mystery "oil consumption indicator" in. If the seller balks at it, there is a clear answer. But what if seller calls your bluff? Dam! I was never good at poker.
 
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Maybe make sure the engine is cold, and then start it and drive in a low gear getting on and off the gas to see if any visible smoke is produced before the cat really gets working? Or play Columbo and look for oil stains in the trunk from carrying a jug of oil?
 
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Or research the year, make , and model to see if it has a reputation of being a burner. I know it doesn't necessarily mean it is or will burn oil but it's better than nothing
 
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Used to be you could ask to view the car on a cold engine; that way you'd see and hear how it started cold. Or assume the worst if they refuse, or if you show up and it's got a warmed up engine. But bad valve guides/seals will smoke at startup, and might be minor consumption. Or relatively easy / cheap to fix. I have to suspect it's a roll of the dice.
 
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Forced rapid deceleration in a low gear...that'll suck out a lot of smoke on a bad burner...some on most cars but a lot more on burners...
 
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Originally Posted By: caravanmike
Very hard to tell, and some people are washing their hands of oil burners on trade in. Seems like ever manufacture has a problem in select categories. With private sellers sometimes cars are not detailed, sooo usually you can see black soot on rear bumper near exhaust exit.
That's what my parents did with their 08 Wrangler. 1 quart / 650 miles is unacceptable. That had a lot of soot and ash in the tailpipe. I'm not sure the dealer would have cleaned out the tailpipe before selling it.
 
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Originally Posted By: Miller88
That's what my parents did with their 08 Wrangler. 1 quart / 650 miles is unacceptable. That had a lot of soot and ash in the tailpipe. I'm not sure the dealer would have cleaned out the tailpipe before selling it.
Bingo! That's what I check. Oil burners will have lots of oily, black residue inside the tail pipe. It becomes tricky with DI engines, as they tend to produce more soot to begin with, but extra soot just from gas combustion will be a lot less oily.
 

friendly_jacek

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Originally Posted By: KrisZ
Originally Posted By: Miller88
That's what my parents did with their 08 Wrangler. 1 quart / 650 miles is unacceptable. That had a lot of soot and ash in the tailpipe. I'm not sure the dealer would have cleaned out the tailpipe before selling it.
Bingo! That's what I check. Oil burners will have lots of oily, black residue inside the tail pipe. It becomes tricky with DI engines, as they tend to produce more soot to begin with, but extra soot just from gas combustion will be a lot less oily.
OK, I did a digital rectal exam on my cars and there was surprisingly little soot in the pipes. They are all non-burners. I don't have a positive control to compare, but it looks promising.
 
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