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Discussion Starter · #1 ·
I am a long time reader of this message board but until now had not felt any need to post. I purchased my Mazda 6i in August 2003 and until two weeks ago had experienced NO problems with the car. I have regularly had the vehicle serviced at my Mazda dealer in Albany, NY, most recently two months ago. Here's the problem...

I was heading home from work two weeks ago and my car was moving effortlessly along the winding two-lane highway I take during my daily 30-mile commute. As I began slowing down to make a left-hand turn I noticed the "Check Engine" light go on and as I came to a stop I realized my engine had shut down. There had been no forewarning of trouble -- no shake, shimmy or hesitation -- leading up to the shut down. When I tried to start the car again it tried to turn over but did not catch. Fortunately, no one rear-ended the vehicle while I was stalled in traffic and about five minutes after the engine died a couple of guys stopped to help me push the car into a relatively safe location while I waited for the police (my car stalled at a dangerous, high-traffic intersection) and tow truck.

Since I stalled out 50 miles from the nearest Mazda dealer I had the vehicle towed to the mechanics who have taken care of our other cars for the past 20 years. To make a long story short, after working on the car for over 10 hours they threw in the towel. They were unable to get the car started and they had run out of ideas as to what was preventing the car from starting. At this point I had no choice but to pay for a second tow up to Albany.

Last night I got a call from Mazda service saying the car could not be started and that they were unsure of what the problem is. They did say, however, that I only had 1 quart of oil in the engine and I might have a damaged motor. When I asked how common is was to burn up that much oil so quickly I was told that the service records indicated I hadn't had an oil change since I had 45,000 miles on the car (I have 84,000 miles on it). When I suggested he re-check his records he did admit he was wrong and that the last change had been made at 79,000 miles. So apparently the vehcile burned all but a quart of oil during the past 5,000 miles. There was no visible sign of a burn-off (yes, I know about the catalytic converter), nso sign of an oil leak, no warning light indicating "low oil", no indication the engine was running hot, and no sign of impending trouble.

I am not sure where this is going but after two weeks and no answers I am getting increasingly frustrated. My questions to the board: Have you ever encountered a problem with a silent stall at speed (sensors indicate my car was going 47 mph when the engine died)? Are you aware of problems with malfunctioning warning lights? Have you encountered a problem starting your Mazda6 that was found to be caused by a non-mechanical malfunction? Any insight you guys can offer would be much appreciated as I don't think I'm going to get any answers from the dealer. Thanks in advance.
 

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Its very rare for a vehicle to stall at speed and unable to be restarted. Unfortunately it sounds as if your situation is directed related to the lack of oil in your engine. If you were only operating on one quart, there is enough oil for the pump to provide oil pressure (which is why you never saw a "Low Oil Pressure" light, it is not related to oil level unless you have zero oil), but not enough for adequate lubrication and cooling. Your only warning of impending doom would be if you regularly check your oil. Its rare, but all cars are prone.

In the V6 subforums, it is common for PCV valves to fail and cause enough consumption to the point of engine failure, such as you describe. Oil, in this case, is burned so cleanly that you will not see any smoke. You may be the first known 2.3 I4 owner to have a PCV related failure.

I have no reason to believe that there is an electrical or computer issue, though only a computer diagnostic would reveal such an issue.
 

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An engine that has a catastrophic failure due to lack of oil will usually make some obvious mechanical noises. An elevated temperature and knocking/rattling would accompany a dangerous low oil condition. I have overheated my Mazda to the point where it shut down, (Crashed radiator...) but the temp guage was in the red and the car restarted after about 15 minutes without a problem. With about 60K miles on my 03 6i, I have basically 0 oil consumption between changes so it's possible that maybe your last oil change was short filled.

After working on your car for 10 hours your local mechanics should have been able to tell if the engine was burnt up. A simple compression test would show them. Starting requires fuel, air, spark, and compression. If you can't confirm these 4 basic things, you probably shouldn't be in the car repair business.... I'm not sure, but it sounds like your not getting the whole story. Maybe the service advisor or mechanic can tell you what they have tried or tested to see what's wrong with the car.
 
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Discussion Starter · #4 ·
An engine that has a catastrophic failure due to lack of oil will usually make some obvious mechanical noises. An elevated temperature and knocking/rattling would accompany a dangerous low oil condition. I have overheated my Mazda to the point where it shut down, (Crashed radiator...) but the temp guage was in the red and the car restarted after about 15 minutes without a problem. With about 60K miles on my 03 6i, I have basically 0 oil consumption between changes so it's possible that maybe your last oil change was short filled.

After working on your car for 10 hours your local mechanics should have been able to tell if the engine was burnt up. A simple compression test would show them. Starting requires fuel, air, spark, and compression. If you can't confirm these 4 basic things, you probably shouldn't be in the car repair business.... I'm not sure, but it sounds like your not getting the whole story. Maybe the service advisor or mechanic can tell you what they have tried or tested to see what's wrong with the car.
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I am certain I am not getting the full story. I spent a good part of the day visiting my Mazda dealer's service department, a rival Mazda dealer's service department and my local mechanics. The competitors suggested that since there was not any evidence of catastrophic failure (knocking, high temp etc.) that they might check to see if the catalytic converter had been plugged. Apparently they have had some customers whose vehicles would not start when this happened. My local mechanics are adamant that I have a problem with the computer. They did not do a compresion test because there had been no evidence of an oil leak and I had told them that the last time I checked the oil (3 weeks previously) there was no problem. They also focused on the computer because they got very unusual voltage readings from various sensors, the details of which I will not get into as my knowledge of automotive electrical systems is near zero.

My Mazda dealer's service tech believes my engine is shot due to a slow oil leak. I asked if he had located the source of the leak and he said they could not without tearing the engine apart. They said they'd be happy to for $91/hour labor, and would be happy to check the computer and catalytic computer as well for a fee. Their recommendation was that I have them install a new engine as it would probably be cheaper than the diagnostic costs. No mention of a compression test, however. When I asked if there was any test they could run to see if there was an active leak they stated that there was none that could be done unless the engine could be started.

The new engine is a non-starter, as I no longer have much faith in the safety of an engine that stalls at speed for reasons that can't be explained unless I invest an open checkbook in the effort. The dealer has also suggested that I trade in the car for a newer model. Frankly, if I end up taking this course I will do it with their competitors.

Anyway, thanks to both of you for your responses. I've got a lot of thinking to do this weekend. I will certainly ask about the compression test when I speak to the dealer on Monday.
 

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Your car is only 4 years old -- shouldn't it be covered by the powertrain warranty still at this point?
 

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Well... For one thing it the engine is still spinning over it is probably not blown. Typically an engine that dies from lack of oil will seize up. And the fact you got no warning lights leading up to this also indicates it is not a blown motor. Sounds like the techs at the mazda place do not know what they are doing so their idea is to just replace the whole car. Great idea, but quite costly. It is scary but alot of mechanics out there do not really know how to diagnose cars. If the computer tells them a sensor is bad sure they can replace it, but if the computer says everything is green, and there is nothing visibly broken, they are at a loss. Some mechanics like to "throw parts at it". This is the practice of just replacing stuff till the car starts working. LOL


If you have no warrenty left, I would check for a better shop that really can fix cars.

My car is a 03 6s, and one day my engine wouldnt start, it would turn over, but wouldnt actually start, and my dealer could not figure out why, he had no idea. luckly for me the car started working again after about 5 hours. The dealership actually seemed upset with me because I had the car towed in, and they had it start right up.

As for the sensors giving odd readings, this system is a CAN system, so the senesors may not give the signals that your average mechanic would understand.

Good luck.
 

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I'm not convinced that low oil will cause catastrophic engine failure as suggested, the engine still may be operable as the OP described.

However, I will agree that a service department that just wants to throw parts at it, does not have a clue what they are doing. It would seem from the further information you've posted that my original guess of an oil-related issue is far from accurate... it would have been assuming a tech worth his tools did a proper diagnosis. Modern OBD-II engines rarely just shutdown without warning. It shouldn't be too hard to diagnose, it just takes a little time and knowledge, something I've found few techs to have. The right diagnostic computer also helps (CAN bus in this case).

As I do not have a service manual, any ideas on the problem will only make things worse.
 
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