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Discussion Starter #1
hey guys, my car is burning a bit of oil, other than piston rings, valve stem seals, gaskets and the pvc what else can cause it to burn, compression is right on the money, plugs are dry as can be, replaced pcv valve twice to be sure, pulled valve covers off valve stem seals are great.. leak down test perfect, haven't checked my precats yet thats all thats left i think, i don't know what else can cause this.. any info would be awesome!! thanks
 

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Please define "a bit" of oil? Is she smokin like a pig or are you just a little low at oil change time?
 

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When I sold mine, I was putting half a liter in a week and I couldn't find any oil leaks at all. It only had 110,000km on it. Unfortunately, it was 10,000km over warranty.
 

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Discussion Starter #5
i have 91,000km's on it, burning maybe a little over a quart and a half or so... around there, its not smoking like a pig, it comes and goes, but when it smokes its just a puff here and there, not constant
 

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For trouble shooting I would go get a piece of clear or nearly clear plastic/rubber hose from Home Depot, Lowes or what ever your local building/plumbing supply store is and replace the PCV inlet tube that runs from just before the throttle body over to the front valve cover. Are you familar with how the PCV system works on our engine? With this in place you can easily see which way the air/oil vapor is flowing. The tube sould remain clean as air flows from the intake pipe down into the front valve cover. If you see oil vapor flow up from the valve cover back into the inlet, you have problems.
This is a great way to verify PCV valve operation. If you put a few drops of dark engine oil from the end of the dip stick into the end of the clear hose where it attaches just before the throttle body, it is easy to see which way and how fast the oil is being sucked. At idle it should be sucked very quickly down toward the valve cover. The flow should slow as the throttle valve is opened when you rev the engine. If the oil drops are blown back into the inlet at any point this is BAD!
 

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If the flow is from the valve cover back into the intake (at any rpm) then either: your PCV valve is stuck closed and you have some degree of piston ring blow-by (the rate of flow tells you how bad), or your PCV valve is fine and you have massive ring blow-by which is more than the PCV valve can vent by itself. ANY BACK FLOW IS BAD! If the flow is slight and you find your PCV valve stuck closed, your lucky and you just need a new valve. In the other case something in your engine is toast. All these test should be done with the engine warmed up.
 

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My exhaust is pretty heavy also.

Definitely burning oil. Consuming quite a bit of oil. Maybe a quart a week.
 

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I've never used any of those Stop Leak or No Smoke engine treatments ... but then again, I think I'm losing about half a quart of oil a day.

You think that stuff would work?
 

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I would replace that PCV hose with the updated thicker hose from the dealer. My oil consumption has gone down ever since replacing it.
 

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I would replace that PCV hose with the updated thicker hose from the dealer. My oil consumption has gone down ever since replacing it.
I will do that. What part do I ask for at the dealer?

Do I just ask for a PCV hose? Anyone know a part number?

Thanx. :)
 

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I've never used any of those Stop Leak or No Smoke engine treatments ... but then again, I think I'm losing about half a quart of oil a day.

You think that stuff would work?

You are loosing 1/2 a quart a DAY?!?!?!? You have a severe problem. What do your plugs look like? Are they all oil soaked or only one or two? Is your PCV hose soaked with oil? Have you done a compression test?

That stop leak crud is only for an engine that you want to get through the last mile. I'd never put it in anything. Especially something you might be rebuilding.

BTW, I burn 1/2 QT between 5k mile oil changes.

BP
 

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I think I have some serious engine issues.

Just had the PCV hose and valve changed. Drove it home and there's still smoke from the exhaust. Is it just burning through the last of the waste oil?

If not, then the PCV hose and valve weren't the culprits.

What else can be an issue with burning oil?
 

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Mazda burning oil

I own a 07 Mazda 6 3.0 replaced two of the cats and after that I have had nothing but problems right now my main problem is the BURNING oil not leaking. I have 143,000 miles on it only have had it for 6 months and got to drive it 2 months before all these problems note I am still making lovely payments on this. Anyhow I have done a compression test, leak down test, changed the PVC valve, compression seems to be good but then I have never really done a leak down test so I am not sure what I need to look for. I have also read some where that I may need to put a quality tune up oil in it not sure about that either. Oh and also there is no smoke whats so ever coming from the exhaust. Changed my spark plugs as well.
 

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One path for oil to escape your engine that is frequently overlooked -- OCV seals.

These can be found where the oil control valves emerge from the valve cover on the passenger side of the car. There is one per bank. When the seals go bad, they can allow oil to escape in the form of vapor. Evidence of this can be found in a particularly strong burnt oil smell in the cabin, oil residue on the hood blanket, oil residue on the surfaces around the OCVs with no obvious leak to blame it on...and even smoke. That's how I found it on mine -- the light was just right, and I saw tiny little puffs of smoke coming out of those seals in time with the engine idle. It was practically invisible.

Also, be sure to check the obvious. Valve covers, seal around water pump/timing cover/etc. Also, the bolts that hold down the valve covers have built-in rubber seals. When they go bad, they can allow oil to collect on top of the valve cover around the bolt.
 

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My car used/burned oil for at least the last 200,000 miles but there was no evidence of it in the exhaust (ie *any* smoke much less blue smoke). It started being 1 quart every 3,000 miles then went to down to 1 quart every 1,500 miles probably at 200,000 or so and then near the end before the rings went in number 6 at 323,709 it was using a quart every 1,200 miles.


Never had any major issues with OCV or valve cover seal leaks (well until the end when blow-by from number 6 forced oil out everywhere!), but did have a minor one from either the front seal or timing chain seal. Not enough to see any drips on the garage floor but occasionally it would drip on the catalytic converter and you'd get a slight oil smell.


Scott
 

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My car used/burned oil for at least the last 200,000 miles but there was no evidence of it in the exhaust (ie *any* smoke much less blue smoke). It started being 1 quart every 3,000 miles then went to down to 1 quart every 1,500 miles probably at 200,000 or so and then near the end before the rings went in number 6 at 323,709 it was using a quart every 1,200 miles.


Never had any major issues with OCV or valve cover seal leaks (well until the end when blow-by from number 6 forced oil out everywhere!), but did have a minor one from either the front seal or timing chain seal. Not enough to see any drips on the garage floor but occasionally it would drip on the catalytic converter and you'd get a slight oil smell.


Scott
As I've said before, this is why they sell oil by the case. Mine started using oil at about 60k miles and used about the same amount until I sold it at 172k. Never a deposit in the plugs, never a cloud of smoke. Ran fabulously.

Sent from the wrong side of the tracks.
 

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I've been getting a faint burnt oil smell in the cabin. I have two obvious issues: It's leaking from the rear OCV seal and the passenger side half-shaft started slinging some grease out - from under the band, not a tear. Might check your half-shaft boots if you haven't already. My passenger side one has started making a pretty good mess. It looks like the serpentine belt and wind are catching some of it and passing it on to the exhaust.

Some motor oil on the bottom of engine and around the oil pan. It's also really oily down by the power steering pump and A/C compressor, though the power steering fluid level hasn't decreased. I've seen faint smoke from where something is hitting the exhaust.

Going to try getting a Breeze clamp from the hardware store for the power steering hose and replace half-shaft when I finally have time. Afraid it might be leaking from oil pan or timing chain cover.

If I didn't love this car so much, it might be earning a spot on Craigslist for sale section.
 
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