Hi, I am having trouble identifying this noise, seemingly coming from the passenger side around the engine bay or drivetrain area. Anyway, doesn’t sound particularly good but at the same time it came abruptly one morning so not really sure. It is way clearer during hard acceleration and when pushing higher revs before shifting, so I did a small 5k Rpm 1st to 2nd pull to demonstrate. Noise seems to be less noticable during higher gear but looks to be linked to torque. When I jab the gas in a torquey gear the noise happens clearly (Entirety of first gear, almost all of 2nd and a bit of 3rd and 4th) Also, seems to happen going straight doesn’t augment while steering and actually seems to reduce. My car is a Mazda 3 2015 manual transmission with 135k kilometres (84k miles). For now, no clutch slippage and still grabby, no noticeable vibrations with clutch down or while releasing, rubber boot on Cv joints doesn’t seem torn at a glance with wheels turned, no grease oil or anything funky on drivetrain from what I can see, and all fluids have been regularly maintained. Please let me know what the problem could be and If it is anything severe. Thank you
Things checked/tested :
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Reving in neutral doesn’t cause sound so unlikely to be exhaust hangers or a heatplate.
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No grease on cv axle and rubber boot is perfect + noise doesn’t increase while turning in fact it seemingly reduces a small bit. Also, those create a completely different sound when worn like clunking.
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Not pilot bearing or release bearing because I would feel the vibrations and hear noises. Played with clutch in neutral pressed down, releasing etc super smooth and no sound + 0 slippage on clutch so not release bearing or fork.
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Not input shaft bearing as noise would happen in neutral on highway and in 5th/6th.
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Not a problem with synchros or gears because sound is identical in 4 different gears.
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Most likely not engine problems because again, would do it in neutral
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Maybe engine/trans mounts, but I don’t think they make that sound and they seem fine at a quick glance + no weird vibrations or clear movement of engine while reving
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Likely not wheel bearings as there are no vibrations at high speeds and the noise itself doesn’t cause vibrations
Sound : https://drive.google.com/file/d/1ITxNTzG4zGtgmMe0vREpvDH58swoAF_t/view?usp=sharing
My first thought was something being loose in the exhaust. I know you said you rev’ed it in neutral, but exhaust sounds different at speed/in motion as opposed to neutral.
Do you have the original exhaust on the car?
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Engine/trany mounts are not what makes the noise generally, a weak, torn or broke mount allows the engine to shift/lift/twist causing the exhaust or whatever to rub/touch/separate or whatever making the noise..
Generally you need to raise the rpms while in gear while foot braking the vehicle safely to check the mounts and or get it up in the air and use a pry bar, if you know where, you can sometimes use a floor jack under the engine to check them also…
Almost sounds like a factory exhaust flex pipe/tube leaking when the engine moves to much due to a weak/bad engine mount…
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Yes, all oem exhaust and clutch
Flexpipe was replaced because of an exhaust leak around 2k kilometers ago that might be the issue bad welds or something. Also, how much would I be looking at to fix the mounts in labor/parts? And is it worth replacing?
I’ve had (3) Mazda 3 cars, and I think they’re fantastic little cars.
Just take the care to a shop (not a dealer), and ask them to check the engine mounts and exhaust system. Even if you have to replace some or all of that equipment…your Mazda still has a lot of life left in it. Personally I wouldn’t even consider replacing the car for either bad motor mounts or bad exhaust. Just spitballing, I’d say under $1000 for either repair.
Only a real estament will let you decide if it is worth the cost. As for any guesses as to cost will mean nothing from one part of the country to another or the shop used.
I would check the exhaust heat shields. A tack weld could have broken on one side the heat shield. so while it may look fine just by looking at it. Try tapping on each corner of every heat shield with the vehicle off and the exhaust is cold, so you don’t get a burn.
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Mounts can be an absolute PITA to write up estimates for with being able to see the vehicle to confirm if the correct mount or not, and even so, sounds like you’re not in the USA, so the best thing to do is take the vehicle to a shop of your choice and have it checked out and priced out…
If you are in the snow belt, then your doors could be about ready to fall off at 10 years old lol, so it ALL depends on the condition of the rest of the vehicle, in my little neck of the woods, unless the vehicle was completely neglected and abused and relatively rust free, then yes it would be well worth it to repair the vehicle…