Several months ago, I was hearing this knocking sound from my engine that would usually manifest itself when making sharp turns. During all this time, the oil pressure warning light never came on except for once when it flashed on and off briefly as I was taking the car to NTB for tires. Come to find out that the engine had virtually no oil in it. I hadn't noticed any obvious signs of an oil leak, but I had them do an oil change and it seemed to have solved the problem. I had the oil changed again at about 5,000 miles later and everything was fine until recently when I started hearing that knocking again. Saw a guy on another Mazda forum say that he had experienced rod knock and will probably have to either rebuild or replace his engine (we both have V6 engines - mine is an '06 with 124K miles on it). So now I'm quietly panicking at work; am I looking at an expensive problem here? I'm taking the car to a mechanic on Friday to see what the deal really is, but I'm worried. If the engine hasn't been beat up too badly and turns out to be OK; what would be involved in replacing the oil pump if indeed that is the problem?

Thanks all, and have a happy 4th of July.

 

I doubt its the oil pump. How often do you check your oil? The knocking you heard/hear was/is a connecting rod hitting the crankshaft due to low/no oil pressure from the lack of oil in the crankcase (therefore lack of oil pressure), it HAS damaged the bearing to a degree and HAS lowered the life of the engine, how much? Who knows but the engine will not live as long as if the oil was checked regularly and topped off, ALL engines use oil to a degree and going 5k miles without checking the level is inviting disaster. What is your oil level at right now? If its low fill it back up and the knocking should go away, if not one of your connecting rod bearings is toast and its only a matter of time before you have a window to the inside of the engine. Watch this clip Budget Supercars part 4 - Top Gear - BBC autos - YouTube this gives a GREAT example of what a connecting rod that is failing sounds like, watch from this point then at 2:23ish the engine lets go. I REALLY hope yours doesn't sound like this yet. Worst case scenario is you need new crank bearings (or just one if your really really lucky).

 

Well, it's been less than 3,000 miles since the last oil change (the manual recommends 7,500 but I typically change it between 3 - 5,000). I've been spot checking the oil, but I'll go ahead and top it off tonight. If the oil pump has failed, wouldn't that lead to rod knocking as a result of at least parts of the engine being oil starved? Any how you look at it, though, I think a rebuild (barring some miracle) is in my future.

 

The oil pump can fail but it is VERY rare that they do, when they do fail you will generally have zero oil pressure, MASSIVE rod knock, declining power and you wont drive for long before it either blows up or seizes, maybe 5 minutes at most. Your oil pressure light is set to go on when you have 6psi or less of oil pressure, if your light is not on when your oil level is correct your pump is most likely working fine. As you said before the light came on when you went around a corner, all the oil that was left sloshed to one side and exposed the pickup tube in the crankcase, this allowed the pump to suck in air and lose prime, once the oil came back the pump had to re-prime itself and re-pressurize the system. All in all I bet your pump is ok but the engine has been damaged due to long term low oil level, does/did it sound like the red car in the video? What is your oil level right now before you top it off? How often is spot checking? I check my 323s oil (along with every other fluid) every 2nd fill up and the 3s oil level every 4th, the 323 uses about a liter of oil every 4,000km and the 3 uses almost zero (always right around the full line). If you do need a rebuild it will most likely just be a bottom end rebuild if the top end is fine, this is the cheapest and fastest rebuild and can usually (depending on car) be done without removing the engine or any major chassis bits. Let us know what else you find out and what the mechanic says

 

Have you ever changed the PCV valve? A faulty PCV valve will cause your engine to use oil. It is not on Mazda service policy to change them. As a matter a fact, i'm looking at the service schedule for 2005 Mazdas. It says to inspect PCV valve after 60,000 miles on a MPV only and change it on a Tribute after 100,000 miles (3.0 ltr model). All other vehicles are not applicable. You have got to be kidding me MAZDA! I say change it every 2 years after the first 3 years. So unless you have changed it, it has never been changed.

 

I need to change the one on my 323, it gets gummed up after a while, I clean it with gas and it works again for 6-8 months then stops rattling when I shake it. Still doesn't fix the rod knock issue but this could be where your oil is going if it is not leaking.

 

Are you cheap! Change it already!
YES to blue part!

 

You try going into a parts store and say Kurbelgehäuseentlüftung!! ROFLOL And I dont want to pay almost $30 for a PCV valve..........

 

WTF is that, German? I'd rather spend $30 than $3,000+ for a new engine and pre-cats! Like the old saying: "You can Pay me now, or Pay me Later".

 

Yep its German LOL. I went to the junk yard yesterday and snagged one off a smashed to bits 323, fits good and rattles good. Any update 93greenstrat? Its Friday here so get your mechanic on the ball!! LOL