'04 Mazda 6S excessive oil consumption

[EPS21]

Hi all, first time poster and I have a problem with this car I obtained some 4kish miles ago in February. It's a 04 mazda 6s with 183k miles on it now.

I obtained the car in California, also got the extended warranty on it to so figured it should be alright as much as driving back to WA state with. When I had a mechanic look at it the first time they said oil level was dangerously low, so I figured it was leaking a lot. It has some minor leaks so thought I'd try to address those first. Replaced the PCV valve and valve cover gaskets were leaking so replaced those too. It's still leaking a few drops overnight so coming from somewhere else too but this thing is definitely consuming way more oil than it's leaking, because after a ~200 mile trip on the highway now its lost nearly half a quart if not more. I've done some research on here and other forums with the PCV being a common problem, but after that still consuming this much what can I do before considering expensive full rebuild or looking for a replacement engine?

I'm a oil noob as well and don't know what brands are best or what can help alleviate this, the oil change it did have was with standard 5w-20 Pennzoil motor. Can high mileage or synthetic/synthetic blends help this at all, or is using a heavier weight oil recommended? Will using some additive or doing something to clean the engine like Seafoam, MMO, AutoRX or whatever else things claim to help oil consumption help? The engine as far as I can tell still performs just fine, did a tune on it recently and runs great, its just using a lot of oil especially on the highways I think. Any input greatly appreciated. Thanks.

 

[901Memphis]

Yes a high mileage oil could help if it's a seal leak. I would never rebuild an old engine for consumption by itself. Just keep adding oil and check often.

I would try Valvoline Maxlife 5w30, bumping up a grade could help some.

The only two additives I would trust for oil consumption are liqui moly motor oil saver or ATP 205, which are usually only available online. Anything you see at the parts store is usually a junk additive. Both of those additives are in my high mileage Nissan and they helped some.

 

[53' Stude]

Maybe check your oil pan and filter mount area for possible leaks. Maxlife 5w30 may help as well.

Oh and

 

[MSTUEBER]

^^^^^ +1

 

[SF0059]

901Memphis is right on the money. I had great luck with Maxlife and Quaker State Defy. Take it up a grade, 5w30 will be good. Also, LiquiMoly Motor Oil Saver works fantastic. I my oil burning Subaru Maxlife and Defy helped, but Oil Saver cut that improved amount in half. It is excellent stuff and you can buy it for a reasonable price on Amazon.

 

[Lubener]

Originally Posted By: car51
Maybe check your oil pan and filter mount area for possible leaks. Maxlife 5w30 may help as well.

Oh and

If the pan has RTV, nothing is going to help. Once the bond has broken it's done.

 

[Oro_O]

Have you looked into the oil ring issue on this generation of Mazdas?

The mileage and oil usage you indicate would be "normal" for a Miata from that generation. The issue is inadequate drain holes in the oil control ring groove on the piston. A number of cars suffer from this pointless engineering oversight in that era - Isuzus, Toyotas, and Saturns are notorious as well as some Mazdas.

I don't know if this common problem carries over to your y/m/m, but I would start researching that. Some get success from piston ring soaks and the using HDEO or other robust, high-quality synthetic oil; others take the pistons out, clean, and drill more drain holes. A more Mazda-oriented forum or individual can tell you if your car is susceptible to this. I am very familiar with the issue but not your car. I have an affected vehicle and have marginal success with soaks and if I could pull the heads and pistons to drill w/o being forced to pull the whole engine out, I'd have done it long ago.

 

[andyd]

Faced with a heavy oil consuming engine, I run the cheapest 10w30 I can find. You're doing a constant oil change.Just change filters every 5-10K What about over filling the sump by a qt or so of diesel and idling the engine for a few minutes? I've never done it. I re-ringed a bug engine that had gunked rings. In retrospect, I bet a diesel rinse could have done the trick.

 

[Vikas]

"extended warranty on 186K vehicle"?

 

[NStuart]

 

[NothingNew]

Originally Posted By: Vikas
"extended warranty on 186K vehicle"?


This.

EPS21 - Have you looked into what the warranty covers or did you just make a note of that in your OP only to ignore it? 3 month/3k warranty?

 

[merconvvv]

200 mile highway trip and you lost half a quart. Before throwing money towards diagnosis by skilled mechanics i would drain the oil and put in qsud 10w30. Then take a 200 mile highway trip and see what happens. Or just drive it and keep an eye on the oil level. Its summer and 10w30 should be just fine.
By the way my expedition has drank oil since new and at around 180k miles still runs very strong just like new. And yes its appetite for oil has been suppressed by qsud 10w30.

 

[Rolla07]

1/2 qt in 200 miles?? Seems like alot. Get it diagnosed and get an estimate of cost to fix, then decide what to do with the car. Be it sell it, fix it or use thick oil.

 

[Graham Piccinini]

One of my vehicles was consuming 1qt per 100 miles. I added 1qt of Marvel Mystery oil to the crankcase when it got low, and then changed the oil after 100 miles. I stayed with synthetic oils after that and my consumption improved to 0.5qt-1qt per 4000 miles. Try Marvel Mystery oil 100-300 miles beforw an oil change.

 

[PimTac]

I like the suggestion of 901Memphis. Valvoline Maxlife. Check for leaks while the engine is running. One quart every 4-500 miles is not a leak, that's a hemorrhage. Check out the rear main seal. Check the plugs for fouling too.

That extended warranty you bought may be worth only as much as the paper it's on. Was that from a California dealer? Read the fine print. I suspect nobody will honor it in Washington.

 

[Olas]

Gaskets, rings or stem seals.
Former is cheap and easy, latter will take a days time and a days spending money.

 

[merconvvv]

1 quart in 500 miles of highway miles does not always imply that the motor is going to fall apart.
My expedition did that from new in 1999.
Runs better than anything i know.

 

[miden851]

Check for visible all leaks first, and use upper viscosity grade or high mileage oils; also I would be doing a sooner oil changes then a regular oil change for first 2-3 intervals

 

[BAJA_05]

Keep en eye on that oil level "often" so you do not grenade it!!!! Good luck!!!

 

[Audios]

Try a higher mileage, thicker oil and monitor the results. Sometimes it can take a few changes to see a big difference, sometimes theres no difference at all. If nothing changes, just buy the gallon jugs of oil, 10/30, 10/40, 5/30 whatever, and check it every fill up. You can run alot longer on that filter since its always getting new oil through it.