[tropmonky]

I need to get this off my chest, plus maybe someone will have a suggestion that can help me.

I have a 2006 MS6 with extended warranty... A month ago I noticed my gas mileage tank from avg 21-22mpg to 16-17mpg. One day after getting out of the car I smelled a strong oil smell from the bottom of the car. I took it to a local place (the Mazda dealership is like 30min away and I was wanting to get a quote for diff fluid change). They put it up on the rack and found that all the fluid had dripped out of the rear Diff due to a seal problem.

I took the car into Mazda and they sealed it back up and filled it up with fluid. I figure that the rear end most likely ran dry/semi dry for over 300 miles and asked if they were going to replace the bearings in the rear end, they said "nope".

I've driven the car through a few tanks of gas now and I'm only getting 16-17mpg no matter how I drive, even when I put the economy map on the car I still only got 17.5mpg with lots of FWY driving. There is clearly still an issue, so I took the car into Mazda again today. They ran every diagnostic on the car and came up with nothing. The drop in MPG started with the rear end loosing fluid and they refuse to do anything more than they already have without definite proof that there is something wrong like a car code or something breaking.

The service rep told me to call MEPP (mazda extended protection program?) and talk to them about it. They simply stated that they can't do anything and it's up to the dealerships to find what's wrong and fix it.

It seems like MPG is getting slightly worse over time (over the past 4 Tanks). I'd really not get stranded out if the rear diff finally decides to grenade, but at least then they'd have to do something about it.

I've been around auto racing all my life and have always known that if a "wet" bearing is ever run "dry" you need to replace it, even if it appears to be okay... I asked the service rep "what happens if my MPG drops by 50% overall" he replied "bring it in and well look at it"... I then said noted that he said they can't do anything unless something appears broken or the cpu tosses a code and he said "that's correct".

So it looks like I'm suck with a car that is getting worse and worse MPG as gas is about to hit $4gal here in CA, costing me money, and worried that the rear end could possibly grenade at any time. I'm not happy about this, and I purchased the extended warranty so that I wouldn't have to lay out $ to get drive-train shit fixed!

Anyone have any ideas, Mazda people I could call, ect?

Meanwhile I may be forced to drop the MS6 and get something else... I'd rather not, being here in CA all cars have a 9.75% Sales tax and insurance is fricken expensive in Los Angeles, except the MS6 seems to be the same as a normal mazda 6 4door, so it's cheap..

Thanks for any info and for reading my rant,:huh:

 

[Dephect]

I got an extended warranty from Mazda after purchasing my MS6 used. 2 weeks later they denied a claim to replace front bearings and hubs. I walked inside and asked for my cash back.

As for your issue, I'm almost sure that the bearings need replacing and you should call Mazda and ask for the number to speak to a representative of MazdaUSA. If not rebuilt, then the whole rear diff needs to be REPLACED. I went through 3 rear-ends on my Rx7. once due to a seal issue (ran it at the track like that too *snicker*) It's not pretty afterwards.

 

[flipper66]

have you considered taking it to a shop other than mazda and getting a 2nd opinion?

it might cost you 100 bucks or w/e for a diagnosis fee....... but atleast you could come to them with something more firm than your word.

getting mazda to pay for anything is going to be time consuming and difficult so spending a few bucks for your piece of mind might be worth it.

PS that is a huge loss of MPG, even if you factor in changes into winter blend..... have you considered there might be another issues? Specificly the PCV and plugs.

 

[Sobe]

have you considered taking it to a shop other than mazda and getting a 2nd opinion?

it might cost you 100 bucks or w/e for a diagnosis fee....... but atleast you could come to them with something more firm than your word.

getting mazda to pay for anything is going to be time consuming and difficult so spending a few bucks for your piece of mind might be worth it.

PS that is a huge loss of MPG, even if you factor in changes into winter blend..... have you considered there might be another issues? Specificly the PCV and plugs.

Would definitely take it to another tech.

 

[tropmonky]

It sounds like I gotta make some calls... I'm running 1step colder plugs and using an access port. Even with the economy flash I'm unable to get over 17-18mpg on the fwy.

The problem with this issue is that the problem can't be seen or felt if the bearings aren't up to speed. So even if you take the diff apart and were to inspect the bearings (spin them with your hands) they would most likely appear "okay".

I live in Los Angeles, perhaps I should just try stopping by Mazda and knocking on there door, LOL :lol: .

First I think I need to start calling people. Anyone have a good starting point??

With Audi 2007 S4's going for around 24K now I may just jump ship... But I'd rather not because my insurance and MPG would go up... and that's just tossing money in the fire.

Thanks guys!

 

[flipper66]

Why not ask the service advisor or tech to go for a ride with you.

Then they can experience what you are feeling.

 

[TiGraySpeed6]

IF it's your rear diff causing a change in mileage, it would have to be mechanical drag doing the job. How does the car feel? does it feel sort of like the e-brake is on?

For that matter, you can also lift the e-brake one notch to momentarily disable the rear diff - for a change that big in mileage you should feel a very noticeable change.


clean your MAF.
verify, then clean your air filter anyway.
pull your plugs & confirm they are as expected.
verify your tire pressure
check that your alignment/toe setting isn't hugely off

I've even see a bad A/C compressor effect mileage......

 

[TiGraySpeed6]

Now that my coffee has started to kick in, I'm second guessing my post above in regards to using the e-brake to temp. disable the rear diff-

If it is a drag issue as described in the first post, it is, I'm thinking now, entirely possible you won't necessarily feel any major difference.

apologies for typing prior to caffeine...

 

[FORZDA 1]

The mileage problem is NOT the diff bearings. There is NO connection. The rear diff has a fluid temp sensor that will set the AWD light on the dash if the diff overheats. The bearings are FINE unless you hear a definite speed-related groaning or roaring noise. In a racing environment you may want to replace any bearing that even MAY have been overheated, but in a street car, even a high performance street car, you will NOT replace a large diff bearing unless it is making noise, as in pitted or clearance worn. If a diff bearing was tight enough to cause rotational drag sufficient to take a big fuel mileage hit, you couldn't stand to be in the car driving as it would be howling so loud it would hurt.


Ok, now that is out of the way, you can focus on the actual problem, if there is one. FIRST, have you checked tire pressures and wheel alignment? Brakes dragging from ice/corrosion buildup? Hit a curb lately?, You have an AP, so have you logged things like fuel trims, AFR, etc. to try and identify whether you have an engine problem, a fuel leak, or just a neighbor screwing with you?

Edit: I see you're in LA, so disregard the ice, but corrosion is still a possibility

 

[tropmonky]

Thanks for all the ideas guys! It's always nice to be able to bounce off stuff with others when the dealership just puts their hands up and calls it quits.

Interesting note about the rear diff heat warning; I would have thought it would have gone off when driving the sucker DRY for 300+ miles and getting out and seeing smoke coming from the rear end, but it didn't ever turn on....

Lucky for me the other day I left in the morning after letting the car warm up as I always do, and when I pulled out into traffic the car bucked and tossed a check engine light. I canceled my days duties and drove directly to the dealership, and drove very gingerly might I add.

They checked the code (I could have done so with my access port, but didn't) and found it was a Mass air sensor code. They pulled the sensor and found it to be pretty much fried looking. I have a Mazdaspeed CAI and therefor the sensor was covered under my extended warranty (WHEW). My down payment was only $100 and if it wasn't under warranty they would have charged $475 for the whole sha-bang.

The car is back and is running much better! I still need to put my Access Port Tune back on it, but even on the stock tune it's running much better.

I'm really amazed that they didn't pull the mass air sensor the first time I brought it in to get checked up. I'd think that it would be a standard component to pull and check if a car ever comes in with horrible gas mileage. But I'm guessing they are lazy and simply plug the car into the computer and that's about it...

From now on I'll be checking sensors on my own when things go out of wack again. Nearly every car I've owned has needed the mass air sensor replaced at some point or another!

 

[amunre]

You should also be cleaning your CAI filter every 10-15k miles per the included instructions. I'd also buy some MAF sensor cleaner and spray down that little MAF diode/bulb at each of those intervals, while your at it...

 

[crossbow]

My down payment was only $100 and if it wasn't under warranty they would have charged $475 for the whole sha-bang.

FYI for future reference. The MAF is 145 dollars online, and 2 screws and roughly 30 seconds to replace. If you can open the hood and hold a screwdriver, you can replace the maf!

Even at 2x markup, and a full hours labor, that still doesn't come to 475!!! I'd be wary about that dealership.....

 

[flipper66]

FYI for future reference. The MAF is 145 dollars online, and 2 screws and roughly 30 seconds to replace. If you can open the hood and hold a screwdriver, you can replace the maf!

Even at 2x markup, and a full hours labor, that still doesn't come to 475!!! I'd be wary about that dealership.....

word. you do need to know righty tighty, lefty loosy too...