Burning Oil

[mazdaagain]

I have a 2005 GT Sedan with 220,000 km and am burning a ton of oil. I'm down about 1 litre for every 1,000 km driven. Is there anything that I can do to reduce or fix this ?

[Leafs_Nation87]

Check the head gasket....you may need a new one.....is the smoke coloured?

Is the drain plug tight? Sometimes when the oil is changed the plug isint tight enough....check the bottom of the car for leaks....you never know

Good luck....hopefully its nothing serious

[Leafs_Nation87]

valve stem seals or the pvc...get it checked by a regular mechanic....they can check the plugs and do a engine compression test....

[aris]

What grade of oil are you using?

If your using 5w20 you might need to go to a thicker oil. I know years ago I had a tercel as a winter beater and it burned oil... I started putting 10w30 oil in it... It didn't fix it but it slowed it down.

[Harbour Rat]

Did the oil consumption gradually increase over a few months or did it seem to spike suddenly? If consumption has been slowly increasing for a several months or a year then good old fashioned mechanical wear and tear may be the cause. At 220,000 km it is possible you could have worn rings/cylinders or leaking valve seals.

If it started fairly quickly I'd be more inclined to think it is the PCV valve. This is a pain in the ass (ie, lots of labour) to replace, being located under the intake manifold but the kind of oil consumption you describe will cause some very, very expensive problems if you don't get it fixed ASAP.

[krimsalt]

At 1L/1000km, it would be blue coloured smoke when you drive, or at least a strong scent of oil when you are sitting and idling.

Another problem (very common) is when the mechanic changed your oil, they strip the oil plug's threads or the threads on the pan where the plug goes into. This causes a perfect screw in, but has a slow leak. It may also be from a cracked or damaged oil plug gasket (small washerlike ring that goes around the screw).
If the plug is damaged there are many different ways to fix it depending on severity of the crack.

You may also be externally leaking from somwhere else, such as main crank seal, oilpan gasket, head gasket, oil pump.

Check your coolant, if you see brownish coloured (similar to chocolate milk), then you may be leaking into your coolant system. But I highly doubt this unless you are not noticing a coolant overflow rise.

Note: If valve guide seals are gone, it wont cause noticeable lack of compression.
Piston Rings being worn are commonly paired with a rod-knock, but not always.

Doing a compression test on the cylinders would be a modest idea, that would narrow the issue down to piston rings, and in some cases, head gasket. Also compare spark plugs to see if any have been fouled by oil.

good luck, I hope it's nothing detromental

[Harbour Rat]

You would think 1L/1,000 km would make lots of blue smoke but there are numerous reports I'm too lazy to link which describe similar oil consumption and some mention no smoke.

The theory seems to be the catalytic converters burn the oil completely enough for there to be no smoke. I have no idea, I suppose it is possible, especially given reports of catalytic converter failures in some of these cases. I guess if you keep the oil topped up for a few months the engine won't grenade but you end up running a few dozen gallons of oil through the converter and eventually it burns out. Again, I don't know, it sounds plausible but so does Democracy if you're drunk enough. Who knows?

If the oil was leaking at that rate the under side of the car would be covered and there would be too much oil to ignore on the ground underneath it all the time. There would probably be smoke and/or a burning oil smell too; I cannot imagine that much oil leaking out and none hitting the hot exhaust.

As noted, a head gasket failure is possible but there would be other symptoms, especially with the kind of oil consumption described here. The car would get up to operating temp very quickly and/or overheat all the time. There would be coolant consumption and/or far too obvious to ignore cross contamination between the oil and cooling systems.

I'm going to stick with my PCV valve theory. It is a pain to replace so I doubt most people ever bother and given the location there is no doubt the engine would suck massive quantities of oil once the PCV valve gets a bit sticky. At 220,000 km it is long past due for service if it has never been done.

I don't know if it is a feasible DIY job but I gather some Ford mechanics have found a way to replace the PCV valve without removing the intake manifold on Focuses which use the Mazda engine. Seems to me it required a very long set of 90 degree needle nose pliers and a willingness to apply lots of profanity. On the plus side, if you can replace the PCV valve yourself without taking off the intake manifold the cost should be pretty low.

[acrossthec]

I've got an '04 GT hatch (2.3) at 125,000 km, burning tons of oil. We're talking 1L every couple weeks - at least. I was running the standard 5w20, but decided after reading around the forum to switch to 5w30 and it's slowed down significantly.

I'm a little concerned given the low mileage. I don't drive it that hard, mostly highway to/from work everyday. I dropped it off at Direct Mazda this morning for an oil change and to replace the spark plugs (120k service). I had them pull the plugs and the tech said they were clean, except on the threads which suggests there is some leakage (?). I've asked them to do a compression test just to rule it out, as the PCV is a bit pricey to replace and I'm on a budget these days. If the compression test turns up some problems, I have an aftermarket extended warranty that may cover it.

I'll post up the results of the compression test and see what you guys think when I get the info, hopefully later today.

[acrossthec]

Compression test was all good, 80/180 across the board. PCV next I suppose, going to see if I can take it to Jimmy at SP rather than the dealer, save a few bucks since it's like a two hour job to replace a $25 part.

[doughboyr6]

i'm heading down the same road....black smoke, burning oil smell, low oil frequently. i think i need to take it to jimmy also. i hear there are so many possibilities....could be the spark plugs, cat, pcv....or worst case; engine.

[mazdaagain]

No black smoke, no blue smoke, no leaks (no stains on the driveway)... seemingly no noticeable loss in power. I'll try going to 5w30 from 5w20.

[Cosmo77]

Have your plugs checked by a "great' mechanic that knows how to read plugs. And start recording your oil consumption vs mileage.

Mazda3's can go through quiet a bit of oil like you are sudgesting without every showing excessive "blue" smoke, because the catalyst system burns the oil so well. If you have no leaks and your PCV system is ok (ALSO make sure your air filter is very clean)...you most likely have a "oil ring" or "scavenge ring" problem in your engine.

[Kiyomi]

agreed on changing to a denser oil.

[Harbour Rat]

If you are burning 1L/1000 km then switching to thicker oil is not even a band-aid solution. It is possible it may slightly slow down oil loss for a brief period but whatever the underlying problem is it will only get worse and oil consumption will continue, maybe even get worse. That kind of oil consumption indicates a real (not necessarily fatal, but real just the same) problem that must be addressed ASAP or you will end up paying for a new engine.

[Kiyomi]

If you are burning 1L/1000 km then switching to thicker oil is not even a band-aid solution. It is possible it may slightly slow down oil loss for a brief period but whatever the underlying problem is it will only get worse and oil consumption will continue, maybe even get worse. That kind of oil consumption indicates a real (not necessarily fatal, but real just the same) problem that must be addressed ASAP or you will end up paying for a new engine.

the engine is 200,000 km on it, a used engine can get for like 1,500-2,000., if ur paying that much in oil and repairs, mite think about getting another engine.