Hello there.
I need some advice.

I've had a Mazda 6 for seven months - it's done 7,000 miles.
Last month it started making a strange knocking noise, so I took it to Mazda (I'm in the UK, by the way) so they could take a look at it.
To cut a long story short, it was out of oil, and, after a few letters, Mazda are refusing to repair it under warranty because I said that I checked the oil once a month, and it says in the handbook that I should check it once a week.
Before everything went wrong, the oil level hardly moved - then, somehow, it managed to use all it's oil in two weeks - but that's not a mechanical problem according to Mazda, it's my fault for not checking the oil often enough.

Bottom line is that a new engine is going to cost £7,500.
Does anyone have any advice about how to get it done under warranty?
Should a Mazda 6 2.3 Sport be able to naturally use all of it's oil in two weeks (or even in 7,000 miles?)

 

I dont think it should be out of oil after just 2 weeks. There is clearly a problem. I go 2 months without checking and I barely lose any oil. You can always call Mazda themselves and ask.

 

Oh, I have - there have been two investigations by Mazda into the situation, and both came out with pretty much the same result: 'Check your oil more often', and 'The oil warning light doesn't always come on'

 

It would have to either leak out or get burned. For you to go through all of your oil in 2 weeks, you'd see blue smoke in your exhaust while it was running.

 

a knocking noise from the engine 99% of the time. means your putting lower-than-required octane gasoline.
mazda6i minimum is 87 (i fillup with 89 for the extra 2 hp)

depending on where u live. u might have accidently put 85octane.

 

This is a known issue where when the Positive Crankcase Valve (PCV) fails and sticks in the open position the intake air sucks out the oil from the engine! People have had entire engines replaced because of it.


Please read this detailed post in another Mazda 6 forum:

http://forum.mazda6club.com/index.ph...c=43344&hl=PCV

 

Bloody hell Grim, that was like reading my own post from a couple of weeks ago!

https://www.mazdaforum.com/m_28909/m..._/tm.htm#28909

My Mazda 6 sport was about 18 months old with about 28,000 on the clock when I started hearing the knocking. I tried every thing, spoke to numerous people at Mazda, and was bluntly told it was my own fault and my warranty was no longer valid!

I did carry on using the car while I sorted out getting a new one, and put about another 1000 on it. I stuck in the thickest oil I could get, specially designed for "worn" engines, and to be honest, now it is just a very slight tapping between 2500 - 3000 revs.

 

My take on this issue is that yes, it is your fault for not checking fluids ofen enough. Beyond that, for the engine to "use" up all the oil would be possible in a number of ways. Could be an over-tightened or loose oil filter or drain plug causing a leak. Could be a bad seal between piston ring and piston wall, due to either defective ring or chaffing to the cylinder wall from insufficient oil flow, this would cause oil to get into the combustion chamber and burn out - this is where you'd see blue smoke in the exhaust. Blown head gasket or cracked head or block could cause oil and antifreeze to mix, the antifreeze to boil, and the oil to evaporate with the antifreeze. If you can find a dealer that will do the work and force it under warranty, but I'm sure your choices are limited there in the UK.

There may not be extensive damage. In my mind, the first step is to change the oil and filter, paying close attention for metal filings(get the oil on your fingers, looking at it in the light for the reflective TINY pieces of metal). If there are no metal filings, you may not be in as bad shape as you thought. If there are filings, the extent of the damage can be significant or even catastrophic.

You could see how much to have mazda or an independent shop rebuild the motor. They remove the heads and inspect the heads and cylinders for damage. If they find no damage beyond normal wear, they just button everything back up with new studs, fill 'er up and you're good, out hopefully under a thousand. If there is some damage, they could see if they can hone the cylinders and replace any damaged parts and you're out maybe a couple thousand. What it boils down to is that you may want to have the motor inspected for damages. You can remove the spark plugs and see if they are wet or fouled, as that could be a sign of oil in the combustion chamber.

Or you could simply change the oil, put in an adhesion additive such as lucas oil stabilizer, and see if she runs fine. Just remember to check the oil AT LEAST once per week. It only takes a couple minutes to do propperly.

I know I didn't cover everything, but this is all I can think of now. I hope I've been helpful to you, and best of luck to you chap!